B. J. Merrill 1, L.C. Cadwallader 1, C. Wong 2 Presented at: FNST Meeting UCLA, August 18 th -20 th Status of DCLL TBM Safety Documentation Containing

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Text of B. J. Merrill 1, L.C. Cadwallader 1, C. Wong 2 Presented at: FNST Meeting UCLA, August 18 th -20 th...

  • B. J. Merrill1, L.C. Cadwallader1, C. Wong2

    Presented at:FNST MeetingUCLA, August 18th -20thStatus of DCLL TBM Safety Documentation Containing RPrS Information12

  • Describe RPrS information available in existing DCLL TBS safety documentationPresent ITER IO RPrS input request and comment on if this information is available for the DCLL TBS.Discuss issues related to giving the required data in a format and at a level of detail that fits ITER IO requirements and schedulePresent conclusionsOverview

  • Safety section of the Dual Coolant Pb-17Li (DCLL) TBM Design Description Document (DDD) GA-C25027 Rev. 3, Nov. 15, 2005,* contains: System description, operational tritium releases, tritium inventory, breeder material radioactive inventory, structural material radioactive inventory, chemical energy and hydrogen sources, nuclear energy sources, accident analyses, evaluation of accidental radiological releases (all in GSSR format)Failure Modes and Effects Analysis (FMEA) for the US DCLL TBM INL/EXT-07-13115, Aug., 2007, contains:Identifies components of the DCLL Test Blanket Systems, estimates component failure rates, identifies and classifies postulated initiating events (PIEs), gives estimates of component repair timesOccupational Radiation Exposure Analysis of the US DCLL TBM, INL/EXT-07-13073, Aug., 2007, contains:Anticipated maintenance activities, radioactive source terms, predicted worker dose rates, and annual occupation radiation exposure estimatesDCLL Safety Documents Containing RPrS Information*The DDD has not been updated, and an update is not planned prior to February 2010

  • Urgent information to be delivered in September 2009 (preliminary level):a) The maximum expected operational releases have to be identified qualitatively and quantitatively for T, ACP and chemicals. Expected coolant and chemical releases have to be identified. T2 operational release in DDD. ACP or chemical releases do not occur during operation, but may happen during maintenance or accident conditions.List of all TBS components (to be available as soon as possible, even before September) and their preliminary (SIC, seismic, etc.) classification (to be confirmed later). (SIC safety importance class component is one that the performs a safety function, such as radioactive confinement, radioactive monitoring, plasma power termination, chemical or nuclear heat removal, fire suppression, etc) Component listing in TBM DDD (Section 2.2.3) and FMEA report, but neither a safety (SIC), or seismic (functional) analysis has been performed to date. Definition of the main interfaces with other relevant ITER systems (e.g., Tritium Plant) Available in Interface Panel Report (A. Ying), and Appendix A of DCLL TBM DDDd)Maximum expected Tritium inventories in all systems and components (e.g., cooling systems, purge gas systems, liquid metal systems,) - Available in TBM DDDe)Maximum expected Activation Inventories in all systems and components Available in TBM DDD and ORE reportTBM Program Contributions to RPrS

  • f)Maximum expected dose rates in the various locations of the TBS components (port cell, CCs locations, Hot Cell,) Available in TBM ORE (except Hot Cell), Hot cell dose rate estimate available in TBM Post Irradiation Study (A. Ying).Waste management: all new elements (compared to the elements listed for ITER) shall be identified and their management outline has to be described in chapter 11 of the RPrS A Waste Management Plan has not been developed for the DCLL TBSFurther required information needed by the end of October 2009:1)TBS conceptual design (envelope design for components not fully defined yet) - Available in DCLL TBM DDD2)Description of the operational status of the various TBS components with relation with the status of ITER (pulses, short and long shutdowns, stand-by, ) Operation of DCLL TBS appears throughout the DDD (Section 2.2.2.5&6), but has not been written coherently. The FMEA also has an overview of the DCLL TBS operation for typical ITER pulses.Results of the main safety analyses. Most of the analyses are probably available but, for each TBS, they need to be collected in a unique coherent set and checked. Available in DCLL TBM DDD.Identification of the TBSs components that have to be classified SIC for confinement. SIC or any other functional analyses have not been performed for the DCLL TBSTBM Program Contributions to RPrS (cont.)

  • Equatorial Port DCLL TBM General Arrangement AEUAEU ComponentsBio-Shield PlugEquatorial Port Inner Space AreaVacuum VesselTBM AssemblyTBM frame AssemblyShieldingPipe well

  • DCLL Helium Loops (AEU) LayoutNot optimized and not all piping thermal Insulations are indicatedTBMVaultHelium AEU

  • DCLL TBM Nuclear Parameters from Detailed 3-D Calculations Tritium generation rate in the PbLi is 4.19x10-7 g/s during a 500 MW D-T pulseFor the planned 3000 pulses per year annual tritium production in TBM is 0.53 g/yearTritium production in the Be PFC is 1.04x10-3 g/yearPeak cumulative end-of-life (after 0.3 MWa/m2)damage in FW is 3.67 dpa and He production is 50.9 He appmTotal TBM thermal power is 0.614 MW (0.24 MW surface heat + 0.374 MW volumetric nuclear heating)This is recent information not available in DCLL DDD.

    MaterialTotal Nuclear Heating (MW)Ferritic Steel0.121Lead Lithium0.218SiC FCI0.028Be PFC0.007Total0.374

  • TBM Decay Heat from DCLL DDDAt shutdown, the total TBM decay heat is ~22 kWContributions are: 4 kW from the F82H structure, 15 kW from Pb-17Li (primarily from Pb-207m), and 3 kW from SiC insertThe decay heat levels after 1 hour, 1 day, 1 year are: 3.5 kW, 1 kW, 0.1 kW, respectively.

  • TBM Activation Inventories from DCLL DDDAt shutdown, the total TBM activity is 2.44 MCi (3.1 MCi including PbLi AES)Contribution is 0.75 MCi from the structure, 1.54 MCi from Pb-17Li (2.2 MCi including PbLi AES), and 0.15 MCi from SiC insertPbLi and SiC isotopes rapidly decay resulting in a total of 0.74 MCi after 60 s The TBM waste disposal rating (WDR, a function of the level long-term activation) is
  • Tritium Release and Inventory Predictions For a tritium generation rate in the PbLi of 2.33 g/year (larger TBM, 1-D neutronics => conservative numbers)For a FS permeator extraction system, of the annual tritium production (at equilibrium after 50 pulses PbLi AES, 3000 pulses for He AES)1.63 g removed and stored in-situ or transferred to T2 building0.47 g permeates into the reactor confinement building (operational release)0.14 g permeates into ITER VV0.09 g remains in TBS, with 0.002 g in the PbLi and ~ same in helium (inventory)Because the tritium release is into building areas that have air detritiation systems, the release to the environment will only be 4.7 mg/year

  • Drain tankPbLi/helium heat exchangerPbLi pumpPbLi Surge tankPbLi Cold trapPermeatorDCLL Ancillary System Components General Arrangement

  • Occupational Radiation Exposure Occupational dose estimates for the DCLL TBS have been made with the QADMOD-GP point kernel gamma-ray shielding codeThe annual worker dose for maintenance activities is 5.2 p-mSv (this dose could drop to ~3.4 p-mSv if EU transport/tube forest is adopted approach uncertain)Plans to update this calculation by using the Attila discrete ordinates code are progressingGenerated Po-210 and Hg-203 do not appear to be a public release concern but may pose a worker riskPredicted Dose Rates for Various Locations and Components

    Location or component (within 30 cm hands on)Dose (mSv/hr)Atop transporter over helium pipes near pipe well8.7x10-03In pipe well next to helium pipes2.4x10-02In front of transporter near double pipe5.2x10-02Atop transporter over double pipe1.3x10-02Atop transporter over heat exchanger1.2x10-02Permeator6.5x10-02Pump5.0x10-02Cold trap7.4x10-02Surge tank3.5x10-02Drain tank8.8x10-02Heat exchanger8.3x10-02Valves3.2x10-02 - 1.4x10-01

  • The ITER IO has requested an SIC analysis of TBS components for the RPrS (also asking for all designated ESPN components to be listed > 370 MBq (0.01 Ci) requires ESPN or comparable standards)SIC components mitigate safety hazards associated with (internal or external to) the TBS, by taking into account the safety function of components (radioactive confinement, heat removal, plasma termination, etc) and the possibility of internal faults, fires, explosions (e.g., H2-air), floods, load drop, earthquake, support system faults (weve asked for guidance from the ITER IO but havent received any yet, but some exists in Section 7.7.3 of ITER Project Requirements Document, ITER_D_27ZRW8)The designation of a SIC translates into a very high design standard, design certification, demonstration of operation during accident conditions, acceptance testing, and in service inspection and testing. Our goal is to minimize the number of components classified as SIC components Based on preliminary discussion with various team members, initial conclusions are:The TBM in-vessel module will not be an SICInitial Thoughts Regarding DCLL TBS Safety Importance Component (SIC) Classification

  • Based on preliminary discussion (cont.):Because the two TBM primary coolant loops (helium and PbLi) are extensions of the VV boundary these loops would be considered SICs based on the radioactivity confinement function of the VVShould redundant isolation valves be placed on helium loop piping leaving the VV, making only these valves and run of pipes up to the valves SIC in this loop with regards to radioactive confinement? This loop will contain a small amount of T2 (370 MBq (0.01 Ci) requires ESPN or comparable standards)Initial Thoughts Regarding DCLL TBS Safety Importance Component (SIC) Classification (cont.)

  • Based on preliminary discussion (cont.):Conservative estimates of Po-210 and Hg-203 inventories are 1.8 Ci and 36 Ci, res