Approved for Public Release; Further Dissemination ... · radioactive equipment and railcars located in Tunnel 1. Parallel to the tunnel design effort, CHPRC awarded a subcontract

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02/07/2018

CHPRC-03585 Revision 0

Project Management Institute 2018 Project of the Year Nomination: Plutonium Uranium Extraction Facility (PUREX) Tunnel 1 Project

2018 PMI Nomination

Project Management InstituteTo be Presented at Project Management Institute - 2018 Project of the YearFebruary 2018

Freeman-Pollard, Jhivaun R

Swenson, Raymond T

Ruane, Tom J

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1 of 2

Via IDMS Data File att.

Approved- IDMS Data File att. Approved- IDMS Data File att.

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Approved for Public Release; Further Dissemination Unlimited

By Janis Aardal at 11:47 am, Feb 08, 2018

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PMI 2018 Project of the Year Nomination: Plutonium Uranium Extraction Facility (PUREX) Tunnel 1 Project, submitted by Jhivaun Freeman-Pollard for public release and submittal by tomorrow. Thank you, Janis Aardal Information Clearance</comments>

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Page 2 of 2

2/8/2018

CHPRC-03585Revision 0

Project Management Institute 2018 Project of theYear Nomination: Plutonium Uranium ExtractionFacility (PUREX) Tunnel 1 Project

Prepared for the U.S. Department of EnergyAssistant Secretary for Environmental Management

Contractor for the U.S. Department of Energyunder Contract DE-AC06-08RL14788

P.O. Box 1600 Richland, Washington 99352



Project Management Institute 2018 Project of the YearNomination: Plutonium Uranium Extraction Facility (PUREX)Tunnel 1 Project

J. R. Freeman-PollardCH2M HILL Plateau Remediation Company

Date PublishedFebruary 2018

Prepared for the U.S. Department of EnergyAssistant Secretary for Environmental Management

Contractor for the U.S. Department of Energyunder Contract DE-AC06-08RL14788

P.O. Box 1600 Richland, Washington 99352

Release Approval Date


By Janis Aardal at 11:48 am, Feb 08, 2018


TRADEMARK DISCLAIMER Reference herein to any specific commercial product, process, or service bytradename, trademark, manufacturer, or otherwise, does not necessarilyconstitute or imply its endorsement, recommendation, or favoring by theUnited States Government or any agency thereof or its contractors orsubcontractors.

This report has been reproduced from the best available copy.

Printed in the United States of America

Performed and presented by:

For the U.S. Department of Energy Richland Operations Office

Nomination for the

2018 PMI

Project of the Year Award

CHPRC-03585

Plutonium Uranium Extraction Facility (PUREX) Tunnel 1 Project

Plutonium Uranium Extraction (PUREX) Tunnel 1 Project CHPRC-03585

Page 2 2018 PMI Project of the Year

Introduction/Summary CH2M HILL Plateau Remediation Company (CHPRC) is pleased to nominate the Plutonium Uranium Extraction Facility (PUREX) Tunnel 1 Project for the Project Management Institute’s (PMI’s) consideration for the 2018 PMI Award for Project of the Year. This submittal describes the $10.48 million project that involved the emergency response, design, and stabilization of a partially collapsed tunnel that houses highly radioactive equipment.

Located along the Columbia River in southeastern Washington State, the Hanford Site is a 586-square-mile former plutonium-production complex with nine nuclear reactors and associated processing facilities. The PUREX Plant is a Hazard Category 2 Nuclear Facility located in the 200 East Area near the center of the Hanford Site, which is owned and operated by the U.S. Department of Energy (DOE), and CHPRC, a prime contractor to DOE, is a co-operator of the plant. The PUREX Plant was constructed in 1952 to recover Cold War plutonium from irradiated fuel elements. Tunnel 1 was built between 1954 and 1956 to permit the unloading of contaminated cask cars without compromising the ventilation system. It was transitioned to a storage tunnel, and the first railcar was placed in the tunnel for storage in June 1960. By 1965, eight 40- to 42-foot-long railcars occupied Tunnel 1, each with hazardous and radiologically contaminated equipment.

The PUREX Tunnel 1 Project was undertaken in response to the unexpected partial collapse of Tunnel 1, which was discovered on May 9, 2017.

When the tunnel breach was discovered, a precautionary Take Cover for the 200 East Area of the Hanford Site was implemented and, upon confirmation of a breach of Tunnel 1, a first ever Hanford Site Area Emergency was declared. The PUREX Tunnel 1 emergency action was featured in more than 60 global news reports.

The PUREX Tunnel 1 Project consisted of three phases: implementation of immediate emergency response actions, development of a stabilization design, and the filling of the entire tunnel with an engineered grout.

Photographs taken during the initial investigation of the collapse indicated that there was a breach into the tunnel. Subsequent investigations determined that the breach into the tunnel was a result of the failure of the tunnel’s wood timber roof structure. The wood timber roof had collapsed into the tunnel resulting in an opening approximately 19 feet wide and 17 feet long, which allowed direct access into the tunnel.

By May 10, crews had successfully completed the backfilling of the collapsed section of the tunnel.

Aerial photo of area of the tunnel collapse.

Historical photographs of PUREX Tunnel 1 water-fillable door and railcar loading into the tunnel.


2018 PMI Project of the Year Page 3

Fifty-six truckloads of uncompacted clean soil was placed through the roof opening at the collapsed area to stabilize the tunnel support walls and cap and seal the tunnel interior space from further exposure to the atmosphere.

In the following days, CHPRC developed a plan to further stabilize the remainder of the tunnel by installing a protective cover over the full length of the tunnel in an effort to reduce soil loading by minimizing or eliminating rainwater infiltration into the existing 8-foot-high soil berm over the tunnel. The protective cover consisted of water-resistant tarpaulin material held in place by cables, eco-blocks and sandbags. The work scope for protective cover installation was performed from aerial lifts using long-reach tools and coordinated efforts from ground crews located at the base of Tunnel 1.

Once the protective cover was in place, a “Best and Brightest” panel was convened using senior company and industry professionals with science, engineering, tunneling and construction experience to conduct an initial analysis of the options. Timeliness was a key factor in evaluating options. Options that involved additional structural engineering calculations, removal of soil overburden or personnel entry for internal inspection of the tunnels were not carried forward due to the unknown stability of the tunnel structure.

Eleven options for continued safe storage of waste in the tunnels were developed. Because the exact cause of the structural failure in Tunnel 1 could not be determined and a significant threat of further failure of the tunnel remained, the plan to void fill Tunnel 1 was the selected option.

CHPRC was uniquely positioned to quickly design and implement the selected option using lessons learned from previous containment, stabilization and shielding projects on the Hanford Site. In June 2017, CHPRC

began developing the conceptual design to place engineered grout into the tunnel to encapsulate the radioactive equipment and railcars located in Tunnel 1.

Parallel to the tunnel design effort, CHPRC awarded a subcontract to local contractor Intermech, an EMCOR Company, of Richland, Washington. While CHPRC was designing the grouting system, developing the Tunnel 1 grout mix and conducting trial batches, Intermech and its subcontractors Ojeda Business Ventures, American Electric and American Rock Products began constructing grouting operation mock-up and started preparation of the PUREX Tunnel 1 project site for the execution of grouting activities. Several site improvements were required to support mobilization of heavy equipment; engineering, construction, safety, radiological and regulatory personnel; and material transport (grout, ecological blocks, etc.).

Grouting of Tunnel 1 began on Oct. 4, 2017. To minimize interruptions in grout delivery by local traffic, tunnel grouting occurred during the graveyard shift. Approximately 521 truckloads (4,434 cubic yards) of grout were placed in Tunnel 1. The grout was placed in several lifts (or layers), and each lift was allowed to set up before the next began. Cameras placed into the tunnel through existing risers provided images that provided assurance to CHPRC, DOE, state and local regulatory agencies and stakeholders that the grout flowed the entire length of the tunnel and around the contaminated equipment on the railcars. Stabilization of Tunnel 1 was completed on Nov. 11, 2017, and turned over to operations on Dec. 21, 2017. The grouting of Tunnel 1 successfully met DOE, state and local regulatory corrective actions to ensure the continued safe storage of the waste in Tunnel 1. In addition, the stabilization of Tunnel 1 contributed to CHPRC’s mission of removing hazards from the Columbia River area and reducing the Hanford Site’s active area cleanup by stabilizing the legacy radioactive equipment in a manner that supports future mitigation.

The PUREX Tunnel 1 Project was delivered one month ahead of schedule with a Cost Performance Index (CPI) of 1.01 for validated baseline cost through proactive project management at a cost of 10.3 million, which was below the DOE-approved total budget of 10.4 million.

DOE has commended CHPRC for its dedication to safety, quality and innovation that directly resulted in the successful completion of the project without a lost workday injury or spread of contamination.

Aerial view of the backfilled collapsed section.



Sponsor Letter Reserved for 2-page pdf letter





Benefits/Value The sudden breach of the tunnel’s roof resulted in the immediate need to mitigate a Hanford Site worker and environmental threat that not only impacted operational activities across the Hanford Site, but surrounding communities as well. As a result, the PUREX Tunnel 1 Project was established with an extremely fast tracked approach to not only seal the collapsed area, but also to structurally stabilize the entire tunnel by the end of December 2017.

The Dec. 31, 2017 milestone was set to lessen the tunnel’s exposure to additional stresses due to upcoming winter season and the additional loading and stress that accumulated snow and water infiltration could cause.

DOE tasked CHPRC with providing a range of options that would provide immediate, as well as long-term interim storage and stabilization of the Tunnel 1 structure. The “Best and Brightest” panel conducted an evaluation of structural integrity options that could ensure continued safe storage of waste in Tunnel 1. The 11 structural integrity options included the installation of various types of protective covers, the construction of facilities directly over the tunnel and the stabilization of the tunnel by in-situ encapsulation of the radioactive equipment via poly foam, earth, sand, clay, or engineered grout.

CHPRC employed all reasonable steps to minimize releases to the environment and carried out measures to minimize or correct adverse impacts to human health and the environment. The immediate actions associated with backfilling the collapsed section and the placement of the protective cover over the tunnel benefited the entire Hanford Site by eliminating the possibility of the spread of contamination from the initial roof breach and future breaches. The immediate actions also enabled hundreds of site employees to resume their daily work activities.

The encapsulation of the radioactive equipment with engineered grout was the selected stabilization method. The stabilization of Tunnel 1 by encapsulating the radioactive equipment provided long-term benefit and value to the Hanford Site workers, the public and the environment by preventing the potential spread of contamination from radioactive and hazardous materials.

Encapsulation of the radioactive tunnel equipment was verified by viewing the grout covering the top of the equipment. The cameras CHPRC placed into various tunnel risers and lances were instrumental in capturing images that verified complete containment of the radioactive and hazardous materials in Tunnel 1.

Completion of the PUREX Tunnel 1 Project benefited DOE’s Hanford Site cleanup mission by lowering the environmental risk of a release of the tunnel contents

in the future while not preventing final waste mitigation. Technical requirements for stabilizing the tunnel were established at the onset of the project. This singular goal enabled the project team to remain focused on the ultimate benefit their actions would foster (protection of the public, environment and equipment) and positive and cost-effective collaboration.

The PUREX Tunnel 1 Project provided the ability for CHPRC, DOE, regulatory agencies and industry subject matter experts to effectively collaborate. The timely solution that resulted from the collaboration served as a positive and cost-effective learning experience.

Photo of Tunnel 1 interior North end. View obtained utilizing camera equipment installed to monitor grouting progress. Equipment in foreground is approximately 50 percent encapsulated by grout.

Photo of Tunnel 1 interior South end. View obtained utilizing camera equipment installed to monitor grouting progress. Red circle shows grout level increasing alongside the equipment, which at the time of this viewing was approximately 25 percent encapsulated by grout.



Schedule The PUREX Tunnel 1 Project P-6 schedule was segregated into phases to capture the tasks and actions necessary to execute the work scope. Three field execution schedules were developed to capture the varying resources and completion objectives necessary to accomplish the PUREX Tunnel 1 Project. The three phases of the project schedule were as follows:

Phase 1: The Immediate Action schedule consisted of the actions and resources necessary to backfill the collapsed section of the tunnel roof.

Phase 2: The Mitigation Action (installation of the protective cover) schedule consisted of the actions and resources necessary to cover the tunnel to prevent wind and water intrusion.

Phase 3: The Stabilization schedule consisted of the actions and resources necessary to stabilize the tunnel to prevent further collapse.

The PUREX Tunnel 1 Project Team (which consisted of CHPRC technical personnel, senior site and corporate management, industry subject matter experts and DOE and regulatory representatives) participated in numerous schedule development and review meetings. Due to the urgency of the event, the P-6 schedule development and status meetings occurred on an hourly, daily and weekly basis as dictated by each phase of the project to track completion of actions at the management and field levels, which fed schedule development and progress.

The urgency associated with backfilling, covering and structurally stabilizing Tunnel 1 required a fast track scheduling approach to execute the associated management, regulatory and field activities. Typically, a fast track approach results in increased costs and the possibility of rework due to quality issues. To reduce the negative effects of fast tracking, the project team implemented a collaborative (open information) team structure.

This resulted in the full cooperation and involvement of senior management, DOE, local, state and federal regulatory agencies and the public in the review and updating of regulatory documentation, as well as design and construction decisions. The stabilization of Tunnel 1 required a substantial change to the tunnel’s structure and required updates to the PUREX Plant design safety analysis, fire hazard analysis, and critical safety evaluation report.

Standard reviews and updates to regulatory and facility operational documentation, under normal conditions, can take months to years and require extensive internal, regulatory and public review and comment periods. However, to support the project’s singular goal of stabilizing the tunnel before Dec. 31, 2017, the process was compressed to facilitate the execution of the work scope.

The completion of the required regulatory and operational facility documents was an early and tremendously important achievement by the project team. The next schedule hurdle the project faced was the ability to obtain the necessary qualified resources and materials on an immediate basis. The project resource loaded the various phase activities to identify just-in-time needs and prioritize the transfer of equipment, material and manpower (work planning, engineering, health and safety, union craft, dozers, tractor trailers, etc.) from onsite and offsite work scope to meet schedule needs.

The final schedule hurdle was the Tunnel 1 Project Team’s inability to physically access the surface or sides of Tunnel 1. To ensure the scheduled sequence of activities would occur as planned, the project team performed several mock-ups, which enabled determining the required sequence and timing of the field activities to ensure the activities could be completed as scheduled.

The subsidence was discovered on May 9, 2017 at 7:45 a.m. and, by 11 p.m. on May 10, the collapsed section of Tunnel 1 was completely backfilled and the protective cover was installed. In 11 days, the project team had completed the mitigation work scope that normally would have taken a year to negotiate, plan, procure, train and execute.

Project schedule.



The Tunnel 1 Project Team’s ability to fast track the P-6 schedule without encountering increased cost, rework issues or accidents demonstrates the project team’s ability to remain focused on the goal and underscores its ability to effectively coordinate, manage and communicate to maintain aggressive schedule dates.

Overview of grout system mock-up at the Intermech Facility, preparing for Phase 3.

First photo of collapsed tunnel signifying Phase 1. Preparing installation of the protective cover, Phase 2.



Cost The PUREX Tunnel 1 Project had not been planned or funded to occur in fiscal year 2017. As such, the funds needed to execute this emergency action were taken from ongoing Hanford Site work scope.

The project team estimated a project the size and complexity of PUREX Tunnel 1 would typically take well over a year to complete at a rough-order-of-magnitude baseline cost of over $30 million. However, due to the breach in the tunnel roof, the project would need to fast track all actions necessary to stabilize the tunnel (encapsulate the radiological materials) by Dec. 31, 2017.

Fast tracking a project typically results in higher total project costs due to rework because of poor quality and/or safety issues. With the enormous complexities associated with structural stabilization of Tunnel 1 (high potential for further roof collapse, limited structural data available, inability to perform a detail structural analysis due to site restrictions, the need to allow for future disposition remedies and impending weather), the project team worked with industry subject matter experts to determine the most cost-effective ways to execute each phase of the project.

For example, the execution of backfilling the breached section with 56 truckloads of uncompacted clean soil within a 24-hour period was accomplished with site personnel and commercial contractors. Once the collapsed section was filled, the baseline cost to cover the entire tunnel was analyzed. To expedite the placement of the cover, the project team used both trained Construction Building Trades and Hanford Metal Trades craft personnel from various Hanford Site contractors. This level of collaboration had not been experienced before on the Hanford Site. However, it resulted in huge cost and schedule savings by eliminating new hire, medical screening and training costs. In addition, the Hanford Building Trades craft and Metal Trades craft personnel had years of hazardous and radiological work experience, which resulted in no rework, high-quality work deliverables and no radiological or contamination events.

In an effort to engage small local business, the project team used small business contractors as much as possible. The fabrication of a protective cover large enough to cover the entire tunnel was direct awarded to a small business who had the necessary resources and material needed to meet the fast track schedule. The fabrication of the cover began in parallel with the filling of the collapsed section.

In addition, the Tunnel 1 Project Team direct awarded the cover installation to Ojeda Business Ventures (a small hub zone contractor) who had access to trained personnel and who had successfully supported recent highly hazardous work scope. To further reduce cost, the project team directed crane specialized material placements to Hanford Site contractor Mission Support Alliance’s (MSA’s) Crane and Rigging group, which had the radiological regulated equipment and trained metal trades craft personnel to execute the work scope.

The project team selected Intermech Inc., an NQA-1 contractor who had previous high-risk grouting experience. The project team also obtained a number of long-lead procurement items (radiation hardened cameras, heavy equipment, etc.) from Hanford Site contractors AECOM and MSA, which helped reduce the overall project cost.

The proposed budgeted cost of the Tunnel 1 work scope was on an emergency basis and authorized in three phases by DOE: first as $3.5 million as a not-to-exceed (NTE), later this was increased to $7 million, and, ultimately, to $10.4 million. Due to the above actions, the project team was able to come in under the proposed budget. The actual cost of the work performed during the three phases of the PUREX Tunnel 1 Project was $10,272,100.



Scope The PUREX Tunnel 1 Project consisted of three phases: implementation of immediate emergency response actions, development of a stabilization design and the encapsulation of the radiological material within the tunnel. PUREX Tunnel 1 was built between 1954 through 1956. The main portion of Tunnel 1 is 358 feet long, 22.5 feet in height and 19 feet wide. The tunnel was constructed using 12- by 14-inch creosote-treated wood timbers. The first 100 feet of the northern part of the tunnel has a 3-foot-thick reinforced concrete wall on the east side. Approximately 8 feet of overburden is on top of the tunnel. The Tunnel 1 railcar access water-filled door is located on the north end of the tunnel and serves as shielding during operations, but was drained and sealed in the 1990s during deactivation.

The finding of the collapsed roof section of PUREX Tunnel 1 resulted in emergency industrial hygiene and radiological monitoring protocols to determine if contamination had spread outside the tunnel. In addition, the 200 East Area of the Hanford Site was placed under a Take Cover as a worker protective measure. Once it was confirmed that no radiological or chemical contamination had been released from the tunnel, the Hanford Site was evacuated. Structural examinations of the roof and sides of the tunnel were conducted by robotic and aerial means. Upon completion the field structural examinations and review of historical design records, it was confirmed that a section of the 12- by 14-inch creosote-treated wood timbers had failed and there was a direct breach into the tunnel. Once this structural information was obtained actions to fill and cover the collapsed section were implemented. Work began on the construction of an earth ramp to provide access for equipment to place soil into the collapsed area.

Since a direct cause for the collapse could not be determined, there was a lack of confidence in the structural integrity of PUREX Tunnel 1. This resulted in the need to immediately interim stabilize the entire tunnel in an effort to prevent any future breaches because of structural failures. A protective cover was fabricated to cover the entire length and width of the tunnel. To eliminate seams that could allow water or wind intrusion, the protective cover was fabricated and installed as a single piece.

The protective cover was 450 feet long by 50 feet wide consisted of water-resistant tarpaulin 8 mil thick material that, after installation, was held in place via plastic-coated wire cables, eco-blocks and sandbags. Due to the instability of the tunnel surface, the protective cover installation was performed from aerial lifts using long-reach tools and coordinated efforts from ground crews located at the base of Tunnel 1.

Once the protective cover was in place sand bags held the cover down while ecological blocks were placed along the tunnel perimeter edge. Wire cables were then strung by an aerial from one ecological block to another to prevent the protective cover from billowing in the wind. With the installation of the protective cover, Phase 1 was complete.

The project team then turned its attention to development and implementation of a stabilization design. The “Best and Brightest” panel proposed 11 options. The options included; retrieval of materials in tunnel, demolition of the structure, installation of a high-density polyethylene cover (40 ml), use of shotcrete and a tent closure, poly foam void filler, low-density fill, construction of a building over the tunnel, placement of a hardened cover over the tunnel, backfilling the tunnel with soil and a combination of soft backfill and soft hard cover. Timeliness was a key factor in evaluating options. Options that involved additional structural engineering calculations, removal of soil Trial batch testing engineered grout for Tunnel 1.

Grout pumping operation, final filling of the south section of the tunnel.



overburden or personnel entry for internal inspection of the tunnels were not carried forward due to the unknown stability of the tunnel structure.

The project team determined that stabilization using low-density cellular fill (engineered grout) was the preferred solution. The technology had been proven on the Hanford Site and across the DOE complex as being able to ensure stability of highly radiological material while removing environmental, public and worker risk. In addition, the technology did not preclude future remedy actions, did not require maintenance and had integrity for decades.

The stabilization design used the existing 4- and 1.5-inch-diameter penetrations in the tunnel roof for cameras and lighting. The ventilation shaft at the south end of the tunnel was also used for cameras and lighting. The grout conveyance system design located the grout insertion point at the roof collapse area. This location also provided enough space to place additional pipes for ventilation, monitoring equipment, lights, and cameras. This area was also determined to have additional room to accommodate a safe work platform close to the pipe inserts, which would be ground supported and capable of safely spanning across the entire tunnel structure. This approach required piping to be routed and inserted through the fill soil and under the existing wood timber roof members in the breached area.

CHPRC determined that passive ventilation through a high-efficiency particulate air (HEPA) filter to the atmosphere was the preferred option. Condensate collection and ducting between the tunnel ventilation point and the filters were specified in the design. The venting system would require no interface with existing PUREX systems or utilities. Three feet of the existing overburden (soil covering) over the tunnel was previously designated as a safety significant design feature in the design safety analysis. Therefore, the

design required removal of all but the 3 feet of overburden to install the work platform. Civil drawings were prepared incorporating room for large equipment (e.g., tracked excavator) to access the overburden removal area. Connection details, installation means, methods and materials were further developed and refined based on information provided from a full-scale mock-up of the design. Following completion of the stabilization design, the Phase 3 encapsulation (stabilization) activities commenced.

Prior to injecting the engineered grout, the project team performed several dry runs (mock-ups) to determine the sequencing of activities and to train workers on roles during the stabilization process. The selected engineered grout admixture resulted in accelerated hydration that provided a sufficient early strength rate to anchor tunnel contents relatively quickly thus minimizing the duration lag between subsequent grout placements/lifts.

Grout admixture quantities were slightly revised from successful grouting project mixtures to provide a low viscosity (i.e., more “flowable”) grout that could flow and self-level up to 300 feet from the collapsed portion of the tunnel to the southern extent of Tunnel 1. Four trial batches were tested to verify that the grout had the required flowability characteristics and did not segregate during conveyance. Field and laboratory tests were also performed on the trial-batched grout to verify slump flow, strength and unit weight requirements.

The field activities associated with Phase 3 began on Oct. 3, 2017, and encapsulation of the equipment in Tunnel 1 was completed on Nov. 11, 2017. Approximately 4,500 cubic yards of low-density cellular fill (engineered grout) was placed into Tunnel 1. The encapsulation activities were completed one month ahead of schedule.

Workers complete grout conveyance system installation in preparation for grouting the tunnel.

Crews setting up work platform in preparation of the tunnel for grouting.



Stakeholders The sudden partial collapse of the PUREX Tunnel 1 roof resulted in a lack of confidence in the structural integrity of the tunnel, impacted every worker on the Hanford Site, as well as the environment and public in the surrounding communities. The event was featured in more than 60 news networks (United States and International).

The immediate stabilization of PUREX Tunnel 1 was the top operational priority on the Hanford Site. Every Hanford Contractor and their employees became a stakeholder in the success or failure of the PUREX Tunnel 1 Project. The resumption of daily operational activities on Hanford Site for over 3,500 workers depended upon completion of the initial mitigation actions associated with the backing filling of the breached roof section and placement of the protective cover.

The Washington State Department of Ecology (Ecology), the U.S. Environmental Protection Agency (EPA), and the Native American Tribes who DOE interacts with were additional stakeholders in the success or failure of the project. The discovery of the partial collapsed roof section at Tunnel 1 on May 9, 2017, prompted Ecology to immediately issue Administrative Order (AO) Docket No.14156 to DOE and CHPRC, which directed the completion of the following corrective actions:

Corrective Action 1: Starting immediately, determine the cause of breach in PUREX Tunnel 1 and assess if there is an immediate risk of further failures in PUREX Storage Tunnels 1 and 2. By July 1, 2017, submit to the Department of Ecology, Nuclear Waste Program a structural integrity evaluation for both PUREX Storage Tunnels 1 and 2.

Corrective Action 2: Starting immediately, develop corrective actions to ensure the safe storage of the waste in the PUREX Storage Tunnels 1 and 2 in light of the above described failure in PUREX Storage Tunnel 1, until a decision on permanent disposition of the PUREX Storage Tunnels 1 and 2 is determined as part of closure under the Dangerous Waste Regulations.

By Aug. 1, 2017, submit a draft report detailing the corrective actions to ensure the safe storage of the waste in the PUREX Storage Tunnels 1 and 2 to the Department of Ecology, Nuclear Waste Program for comment and approval.

Corrective Action 3: By Dec. 8, 2017, submit a draft permit modification to the Hanford Facility RCRA Permit, Dangerous Waste Portion Revision 8C to modify the permit.

The backfilling of the breached section was completed on May 10. Upon completion of the backfilling the Project Team concentrated on the design and procured of the protective cover and support materials; obtained the necessary heavy equipment to install the protective cover, developed work instructions, performed field mock-ups and obtained the necessary regulatory permits to install the protective cover. On May 20, the site wide emergency was declared to be mitigated and over 3,500 Hanford workers were able to resume their daily work activities as they did prior to the breach.

In an effort to educate Hanford Site workers and the surrounding communities, the project team provided PUREX Tunnel 1 information briefings and shared status meeting information with Hanford Site contractors (MSA, AECOM, Pacific Northwest National Laboratory and Bechtel), Ecology, EPA, Tribal members and public oversight organizations. The project team also worked with the communications team to update publicly accessible photos and videos on the DOE YouTube, Facebook and Twitter accounts.

CHPRC and DOE Richland Operations Office successfully provided Ecology with all necessary deliverables as required by the corrective actions listed in AO Docket No.14156. On June 8, 2017, Ecology approved the plan to void fill PUREX Tunnel 1 with an engineered grout mixture. The engineered grout serves as the long term interim stabilization measure ensuring safe storage of the radiological waste in PUREX Tunnel 1 until a permanent disposition remedy is determined.

DOE Public workshop conducted on July 20, 2017.



Global Media Coverage of Event



Risk The project team’s top priority was to eliminate the immediate health and environmental risk posed by the collapsed roof section of PUREX Tunnel 1. The timely responses to the discovery of the breach assisted in mitigation of the immediate risk.

Each phase of the project had specific risk challenges that needed to be removed or mitigated. The project team used engineering modeling (Solid Works) as well as integrated work planning sessions and field mock-ups to learn how overcome the identified risks or mitigate the risks to the extent possible. Based on the various facility, regulatory and safety requirements, the following work restrictions and associated risks were incorporated into the immediate mitigation actions, design and stabilization work scope:

• End state of the grouting operation shall provide structural stabilization of the tunnel structure, and containment/stabilization of contaminated equipment within the tunnel including providing for additional radiological shielding protection around the stored equipment.

• Stabilization efforts shall not impact additional loads to the tunnel roof or tunnel walls.

• Suspended loads (i.e., crane loads) shall not occur over any portion of the tunnel that is not collapsed.

• The engineered grout mix shall be capable of flowing the entire tunnel length, shall minimize voids, shall support future remedial end state actions and shall not increase fire, criticality or radiological hazards.

• Grout placement shall not cause vertical movement (i.e., floating) of contaminated equipment within the tunnel due to buoyant forces resulting from placement of grout fill.

• Tunnel penetrations for grout placement and monitoring equipment installation must be within existing permits.

• The means to verify or document that the grout fully encapsulated all equipment in tunnel upon completion (e.g., cameras and lights in tunnel) must be within the existing permits.

• Continuous monitoring shall be used for detecting and alerting work crews of chemical or radiological conditions in the air and in the tunnel.

• Air displaced from the tunnel by the grout placement shall be passed through HEPA filters to ensure no radiological or airborne contamination release.

• Stabilization activities shall occur on graveyard shift to limit truck traffic and congestion during normal operation hours.

• Daily walk downs and live 24-hour real-time video observations shall be required around PUREX Tunnel 1. The walk downs were to include visual observations and radiological surveys and must be performed 7 days per week including holidays until the grouting operations at Tunnel 1 were completed.

Due to the fast track nature of the project, conventional risk registers and tracking tools were not used. Once the initial response to the tunnel collapse had been completed, the next biggest risk to the project was to ensure the tunnel was not exposed to upcoming weather conditions in its damaged condition. This required continual maintenance of the fast-tracked schedule. The primary technique used to mitigate schedule risk and ensure the tunnel was structurally stabilized by the end of the calendar year was to implement proven and recently deployed technologies, means and methods. While the project team produced some new and creative ideas for preparing and stabilizing the tunnel, the schedule simply did not allow for the time or resources to test and prove these new technologies. Because of radiological and industrial hygiene hazards present in the tunnel interior it was important to use means and methods that were familiar for both the craft and the support organizations like radiological control and safety/industrial hygiene. This kept the project moving forward with familiar techniques and the support necessary to implement these techniques.

A spare filter was fabricated and staged next to the primary filter to minimize grouting downtime in the event it was needed.



Aerial view of mock-up at the Intermech Facility in Richland, WA.

Grouting activities taking place during the graveyard shift.

Mock-up testing of excavation techniques at the Intermech Facility.

Grouting Activities at Mock-Up and at PUREX Tunnel 1



Project Change Management Process/Tools Used to Document and Manage Approve Changes The scope, budget and schedule for all project activities were documented within the Performance Management Baseline (PMB). The PMB was then placed under change control, and revisions could only be made through the change control program via formal baseline change requests (BCRs).

Changes to the baseline can be external when driven by customer directions or internal when driven by project or program changes. External changes were authorized by the DOE Office of River Protection contracting office and, for the tunnel project, took the form of directed and undefinitized changes. Undefinitized changes increased the contract budget base, but instead of increasing the negotiated contract costs, they were placed in authorized unpriced status and could be accompanied by an NTE funding limitation.

External changes were documented through the BCR process, which provided a formal and standardized tracking, approval and communication mechanism for all external PMB changes. The control account manager was responsible for maintaining the baseline, including managing changes through the baseline change control process.

Advanced work authorization BCRs were used to initiate critical work while the proposal was developed or negotiated. This type of BCR was used extensively as the project operated under NTE advanced work authorization funding from the beginning of the project until well into the fiscal year when the project scope was formally incorporated into the contract.

Change-Related Complexities That Had To Be Overcome Due to the expedited nature of the project and the aggressive schedule to structurally stabilize the tunnel, change had to be minimized. Therefore, proven and accepted technologies for investigating, preparing and, eventually, pumping grout into the tunnel were selected early. This allowed the team to draw from recent experiences where these technologies had been successfully used and apply them to the project. Examples of these technologies include the following:

• Selection of proven radiologically hardened camera and lighting equipment that had recently been used in harsh radiological environments similar to the tunnel and came with a familiar and accepted hazard control set.

• Selection of conventional materials for the protective cover and excavation methods (mechanical and vac truck) for installation of the grout conveyance system that were familiar to the radiological and safety support groups and readily available on site.

• Sole source selection of available uncompacted topsoil and the use of a familiar grout mix design from a local vendor resulted in the shortening of schedule durations for submittals, reviews, and approvals.

• Selection of the appropriate procurement contract types enabled the project to respond to unknown challenges. This kept the project team resources focused on solving problems and moving forward.

• Early selection and continued commitment to key resources (i.e., equipment, personnel and the selection of various execution methods) allowed the concept design, permitting and communication efforts to move forward in parallel. If significant changes would have been allowed on any of these project approach benchmarks, it would have added considerable duration to the execution schedule.

Project meetings were held throughout to focus on critical aspects of the project while attempting to simplify the design and work controls and streamline critical engineering decisions while obtaining ownership and commitment from department managers supporting the project. The outcomes of these meetings continued advancement of the project schedule while focusing on the critical path.

Teamwork ultimately was proven essential to manage change. The formulation and regular gatherings of a strong, proactive committee and integrated project team with an ownership mindset was critical.

Welder fabricating a component of the grout conveyance system at the Intermech Facility.



Lessons Learned Although the PUREX Tunnel 1 Project was successfully completed under budget and ahead of schedule, the project was not without challenges. Historical documentation on the tunnel had to be researched extensively to learn and implement critical data into the design and work planning process. In addition, the project team reviewed the lessons learned from past emergency action and stabilization projects at the Hanford Site and throughout the DOE complex.

In addition, the project’s aggressive schedule resulted in the need for field activities to be completed at an accelerated pace. This resulted in the execution of construction and procurement contracts, as well as field activities associated with tunnel design and construction on a fast track basis. This accelerated pace was necessary to ensure that the tunnel was stabilized prior to the winter weather. The lessons learned during the execution of the PUREX Tunnel 1 Project that would be beneficial for future stabilization projects are as follows:

Procurement:

• The sole source use of pre-selected and trained construction contractors enabled the project to proceed at once with obtaining the materials and equipment needed to seal the breach and cover the tunnel.

• The development of pre-determined work scopes is key to awarding work to small business.

Engineering Design:

• Use of a passive ventilation system. Past grout projects used an active (force) ventilation system. However, a passive ventilation system was selected and sized to handle all air displacements during grouting activities. The passive ventilation system was simple to fabricate and test and ended up functioning flawlessly throughout the project. Little to no maintenance or upkeep was required.

Field Execution:

• To eliminate the possibility of a spread of contamination, the Tunnel 1 Project Team implemented a plan to use hammer valves to maintain a segregated tunnel air space from the grout conveyance lines. The team also flushed the grout conveyance lines in lieu of pigging. This method did not produced backpressure or significant air displacement and was a significant improvement over what was experienced on past stabilization projects.

Sustainability Measures:

• The project team was able to borrow existing radiological hardened equipment (i.e., GE Ca-Zoom® 6.2 camera system) from other Hanford Site contractors. This equipment is used extensively throughout the DOE complex and is designed to function reliably in high radiological environments. By borrowing the equipment, the project team did not create any additional radiological controlled waste that would need to be stored on the Hanford Site.

Contractor and Union Collaboration:

• An integration strategy with other site contractors and bargaining and construction craft was paramount to project success.

• Hanford Site subject matter experts were identified and integrated into the engineering design, quality assurance/quality control, safety and field execution, which was a huge factor in the success of the project.

Conclusion Without an integrated, proactive team management approach and resolute adherence to proven project management delivery principles and processes, the PUREX Tunnel 1 Project could not have succeeded. Establishing core project management operating values early in the project made it possible to exceed cost and schedule goals while implementing innovation techniques to manage the complexities associated with the stabilization of high radioactive breached tunnel. The perseverance of the project through the various scope changes, impending winter weather impacts, complex shareholder requirements, cost constraints and an aggressive schedule is a testament to all members of the team and their professional commitment to the principles of successful project management.

Project Achievements

Completed the backfilling and protective cover installation planning and field execution activities in a record 11-day timeframe. Completed the filling of the Tunnel 1 void space with 4,434 cubic yards of engineered grout, one month ahead of schedule. Completed the entire PUREX Tunnel 1 Project ahead of schedule, under budget and without a loss workday, injury or spread of contamination.



Workers preparing for protective cover installation at Tunnel 1. Workers installing the protective cover over Tunnel 1.

The crew after filling the south section of Tunnel 1 with grout.

PUREX Tunnel 1 Protective Cover Installation



PUREX Tunnel 1 Construction and Operations

PUREX Tunnel 1 under construction.

Installation of the water-filled door inside Tunnel 1.

PUREX Facility during tunnel construction.

PUREX Facility operated from 1956 to 1972 and 1983 to 1988.

Documents

Approved for Public Release; Further Dissemination ... · radioactive equipment and railcars located in Tunnel 1. Parallel to the tunnel design effort, CHPRC awarded a subcontract