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LC-FS-PR-018
Radiation Surveys Of Pipe Interiors Using Sodium/Cesium Iodide Detectors Revision 1
Page 2 of 30
TABLE OF CONTENTS
1. PURPOSE AND SCOPE .......................................................................................................4
Purpose ........................................................................................................................4 1.1.
Scope ...........................................................................................................................4 1.2.
2. REFERENCES .......................................................................................................................4
NUREG-1757, Volume 2, Revision 2 “Consolidated Decommissioning Guidance - 2.1.
Characterization, Survey, and Determination of Radiological Criteria” ....................4
NUREG-1575, “Multi-Agency Radiation Survey and Site Investigation Manual” 2.2.
(MARSSIM) ...............................................................................................................4
La Crosse Boiling Water Reactor License Termination Plan (LTP) ..........................4 2.3.
LC-AD-PR-003, “Records” ........................................................................................4 2.4.
LC-QA-PN-001, “Final Status Survey Quality Assurance Project Plan”...................4 2.5.
LC-FS-PR-008, “Final Status Survey Data Assessment” ...........................................4 2.6.
LC-FS-PR-002, “Final Status Survey Package Development” ..................................4 2.7.
LC-FS-PR-011, “Operation of the Ludlum 2350-1 Data Logger and Associated 2.8.
Detectors” ...................................................................................................................4
3. GENERAL ..............................................................................................................................5
Definitions...................................................................................................................5 3.1.
Responsibilities ...........................................................................................................6 3.2.
Precautions, Limitations and Prerequisites .................................................................7 3.3.
Records .....................................................................................................................10 3.4.
4. PROCEDURE ......................................................................................................................10
Efficiency Factor Determination...............................................................................10 4.1.
Pre-Use and Post-Use Operational Response and Background Check .....................13 4.2.
Acquiring FSS Data in Pipe Interiors with NaI/CsI Detectors .................................15 4.3.
5. ATTACHMENTS ................................................................................................................19
Attachment 1, Pipe Detector Efficiency Determination ...........................................19 5.1.
Attachment 2, Daily Pipe Survey Detector Control Form ........................................19 5.2.
Attachment 3, Pipe Interior Radiological Survey Form ...........................................19 5.3.
Attachment 4, DCGLs for FSS of Buried Pipe .........................................................19 5.4.
Attachment 5, Pipe Source Efficiency Positions ......................................................19 5.5.
Attachment 6, Example of Source Efficiency and MDCStatic ....................................19 5.6.
LC-FS-PR-018
Radiation Surveys Of Pipe Interiors Using Sodium/Cesium Iodide Detectors Revision 1
Page 3 of 30
Summary of Changes in this Revision:
Revision 1 – Changes made to align with responses to Requests for Information and proposed
Revision 1 of the License Termination Plan.
LC-FS-PR-018
Radiation Surveys Of Pipe Interiors Using Sodium/Cesium Iodide Detectors Revision 1
Page 4 of 30
1. PURPOSE AND SCOPE
Purpose 1.1.
The purpose of this procedure is to describe the approach utilized at the La Crosse
Station Restoration Project (LSRP) to assess the radiological conditions of the interior
surfaces of piping that will remain at the end-state condition to demonstrate
compliance with the release criteria. This procedure provides instructions for the
acquisition of measurements and recording of data in performing radiological surveys
of the inside of piping using Sodium Iodide (NaI) and/or Cesium Iodide (CsI)
detectors.
Scope 1.2.
This procedure implements the requirements of applicable U.S. Nuclear Regulatory
Commission (NRC) regulations and guidance documents; specifically, NUREG-
1757, Volume 2, Revision 2, “Consolidated Decommissioning Guidance -
Characterization, Survey, and Determination of Radiological Criteria”
(Reference 2.1), NUREG-1575, “Multi-Agency Radiation Survey and Site
Investigation Manual” (MARSSIM, Reference 2.2) and Chapter 5 of the “2.3. La
Crosse Boiling Water Reactor License Termination Plan” (LTP) (Reference 2.3).
This procedure applies to all personnel performing surveys of the interior surfaces of
buried piping for the purpose of Final Status Surveys (FSS).
2. REFERENCES
NUREG-1757, Volume 2, Revision 2 “Consolidated Decommissioning Guidance - 2.1.
Characterization, Survey, and Determination of Radiological Criteria”
NUREG-1575, “Multi-Agency Radiation Survey and Site Investigation Manual” 2.2.
(MARSSIM)
La Crosse Boiling Water Reactor License Termination Plan (LTP) 2.3.
LC-AD-PR-003, “Records” 2.4.
LC-QA-PN-001, “Final Status Survey Quality Assurance Project Plan” 2.5.
LC-FS-PR-008, “Final Status Survey Data Assessment” 2.6.
LC-FS-PR-002, “Final Status Survey Package Development” 2.7.
LC-FS-PR-011, “Operation of the Ludlum 2350-1 Data Logger and Associated 2.8.
Detectors”
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3. GENERAL
Definitions 3.1.
3.1.1 Calibration - The adjustment and/or determination of an instrument’s response
relative to a standard and/or series of conventional true values.
3.1.2 Certification – The use of a derived standard to determine an exposure rate,
activity or other value to the specified and/or required degree of accuracy.
3.1.3 Check Source – A radioactive source, not necessarily calibrated, that is used to
confirm the continuing satisfactory operation of an instrument.
3.1.4 Efficiency – A correction factor determined during detector calibration to convert
the detector output in “counts per minute” to “disintegrations per minute”
assuming a worst-case geometry between the detector and the source.
3.1.5 Final Status Survey (FSS) – Measurements and sampling to quantify the
radiological conditions of a survey unit, following completion of decontamination
activities (if any) to demonstrate compliance with the release criteria.
3.1.6 Performance Test/Response Check – A procedure whereby an instrument or a
component is evaluated against accepted criteria for continuing satisfactory
operation and use.
3.1.7 Turnover - Acknowledgement of cognizant project personnel that a system,
structure, or open land survey unit meets the physical and radiological conditions
necessary to perform FSS.
3.1.8 Acronyms
1.) CsI Cesium Iodide
2.) DCGL Derived Concentration Guideline Level
3.) FSS Final Status Survey
4.) GPS Global Positioning System
5.) LTP License Termination Plan
6.) MDC Minimum Detectable Concentration
7.) MDCR Minimum Detectable Count Rate
8.) NaI Sodium Iodide
9.) NIST National Institute of Standards and Technology
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10.) NRC U.S. Nuclear Regulatory Commission
11.) QA Quality Assurance
12.) QAPP Quality Assurance Project Plan
13.) SER Surface Emission Rate
Responsibilities 3.2.
3.2.1 RP/FSS Manager – is responsible for:
Providing overall guidance and support for the development and
implementation of FSS sample plans and survey packages.
Reviewing and approving all FSS sample plans.
3.2.2 FSS Supervisor – is responsible for:
Providing direction to D&D Manager for pipe access and decontamination
requirements and determining adequacy of pipe access.
Preparing FSS sample plans and survey packages.
Ensuring FSS surveys are conducted in accordance with approved survey and
sampling plans, procedures, and work instructions.
Providing technical direction and guidance for field survey and sampling
activities.
Controlling and implementing sample plan instructions during field activities.
Survey area/unit preparation, isolation, turnover and prerequisites (e.g.,
reference grid layout, identification of working constraints and accessibility
needs).
Providing daily supervision and guidance to field survey and sampling crews
and performing quality checks of field activities.
Overseeing the preparation of samples for transfer to onsite or offsite
laboratories.
Ensuring all necessary instrumentation and other equipment is available to
support survey activities.
Ensures FSS sample plans and packages are properly labeled, stored and
controlled per LC-AD-PR-003, “Records” (Reference 2.4) and LC-QA-PN-
001, “Final Status Survey Quality Assurance Project Plan” (Reference 2.5).
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3.2.3 Administrative Assistant – is responsible for:
Maintains a signature list for FSS personnel to access FSS files.
Maintains a key to the cabinets for FSS file storage.
Serves as Department Records Custodian.
3.2.4 Graphics/GPS Specialist – is responsible for:
Preparation of drawings and other graphics as necessary to be included in the
survey package.
3.2.5 FSS Technicians – are responsible for:
Obtaining and documenting survey measurements in accordance with the
survey package instructions.
Ensuring that all activities, actions, observations and obstructions that are
encountered during the performance of FSS are documented in
Attachment 13, “FSS Field Log” for that survey unit.
Precautions, Limitations and Prerequisites 3.3.
3.3.1 Precautions
1.) Documents and databases containing FSS data and survey records are
Quality Assurance (QA) records when complete.
2.) When documenting survey information, ensure that all QA records are of
good quality and legible. Legibility is determined to be readable and
reproducible.
3.) Isolation and control measures are implemented to ensure that the final
radiological and physical condition of the interior surfaces of the pipe is not
compromised and/or re-contaminated.
4.) Do not use any instrument if improper operation is suspected.
5.) Ensure the length of the cable between the detector and data logger does not
exceed the maximum cable length used during the calibration.
6.) If a signal amplifier is used, then the detector and data logger pairing must
be calibrated, and efficiency factors determined with the signal amplifier in
place.
7.) Whenever possible, a detector should be calibrated at the same time as the
data logger to which it is paired.
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8.) Detectors that fall outside the accepted criteria shall be tagged “Out of
Service” and segregated for further evaluation. DO NOT use a detector
and/or data logger with an “Out of Service” tag attached.
9.) When there is a potential for thermal shock, ensure a protective insulator
with end cap is installed on sodium iodide detectors during survey
operations to minimize damage from shock and thermal changes. The
detector crystal may fracture if the temperature increases or decreases
rapidly.
10.) Radiological detectors that are to be inserted into known contaminated or
potentially contaminated piping systems will be wrapped to the extent
practical to minimize the contamination of equipment. This can include the
sleeving of cables and fiber rods and the application of tape to exposed
detector surfaces.
11.) Do not use liquid decontamination solutions on exposed electrically
energized equipment.
12.) Do not insert radiological detectors into areas of piping where video shows
standing water, or where significant physical interferences exist that may
damage the detector.
3.3.2 Limitations
1.) All attachments described in this procedure may be generated electronically.
If electronic attachments are used, then the physical layout of the attachment
may be modified provided the intent described in this procedure is not
changed.
2.) Detector parameters are determined during calibration and shall not be
altered during the field operation of the equipment.
3.) If a detector fails a pre-use or a post-use background count, the most likely
causes are the inadvertent contamination of the detector housing, the
inadvertent contamination of the pipe or the introduction of another
radiological source into the vicinity of the background count. If the cause of
the increase in background is readily apparent or can be mitigated (e.g.,
decontamination of the detector housing or pipe), then the background count
may be repeated without any additional action. If the pre-use or a post-use
background count continues to fall outside of the acceptable range, then a
new efficiency factor determination must be performed in accordance with
section 4.1.
4.) After completion of the FSS in a pipe, the sample plan is reviewed for
completeness and the data validated in accordance with LC-FS-PR-008,
“Final Status Survey Data Assessment” (Reference 2.6) before sample plan
closure and the reporting of results.
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3.3.3 Prerequisites
1.) A FSS Sample Plan will be prepared for pipe surveys in accordance with
LC-FS-PR-003, “Final Status Survey Package Development”
(Reference 2.7). A sample plan may be prepared for individual runs of pipe
or grouping of pipes based on classification, or location. A folder
designated as the FSS package should be utilized to keep original
documents. The folder shall be controlled in accordance with the record
quality requirements of LC-QA-PN-001, “Final Status Survey Quality
Assurance Project Plan” (Reference 2.5).
2.) The equipment and services necessary to perform radiological surveys of
pipe interior surfaces may include the following:
Miniature video camera and lighting A.
Video console with recording capabilities B.
Appropriate length cables and sleeving C.
Fiber Push/Pull Rods, Fish Tape and Measuring Tape D.
Appropriate sized NaI/CsI radiological detectors E.
Radiological data logger (single channel analyzer) F.
Field communications equipment G.
Flexible radiological sources and/or point sources H.
Appropriate sized clean pipe I.
3.) Decommissioning activities having the potential to contaminate the interior
surface of the pipe to be surveyed must be completed prior to the initiation
of FSS.
4.) Prior to inserting a radiological detector into a pipe, ensure by remote video
that the pipe is free of obstructions and is as dry as possible.
5.) Instruments and/or detectors shall be inspected daily for mechanical damage
prior to and following field use. These inspections are documented on
Attachment 3, “Pipe Interior Radiological Survey Form” by circling “Sat” or
“Unsat.”
6.) Prior to using any survey instrument, the current calibration must be
verified.
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7.) The efficiency factor for each detector and data logger pairing used for FSS
pipe surveys shall be determined in accordance with Section 4.1 upon
receipt after calibration, as directed by the FSS Supervisor, or following any
repair or maintenance.
8.) A response and background check will be performed in accordance with
Section 4.2 for each detector and data logger pairing daily prior to use (Pre-
Test) and daily upon completion of surveys (Post-Test).
Records 3.4.
3.4.1 Attachment 1, Pipe Detector Efficiency Determination
3.4.2 Attachment 2, Daily Pipe Survey Detector Control Form
3.4.3 Attachment 3, Pipe Interior Radiological Survey Form
4. PROCEDURE
Efficiency Factor Determination 4.1.
NOTE
The maximum length of the detector cable used will not exceed the length of
the cable that was used during the calibration of the detector and data logger
pairing. The length of cable shall not exceed 150 feet.
4.1.1 Select the detector and data logger pairing, as well as the length of cable to be
used. Ensure the detector and data logger pair have been response checked in
accordance with LC-FS-PR-011, “Operation of the Ludlum 2350-1 Data Logger
and Associated Detectors” (Reference 2.8).
4.1.2 Record the pipe size, instrument/detector type, serial numbers, calibration date,
calibration due date and the detector cable length for the detector and data logger
pairing on Attachment 1, “Pipe Detector Efficiency Determination.”
4.1.3 Ensure that the parameters settings for the data logger (e.g., voltage, etc.) are set
to the values specified for the primary radionuclide to be surveyed per the
certificate of calibration for the paired detector.
4.1.4 Connect the detector to the data logger using the appropriate cable length with the
data logger de-energized.
NOTE
Ensure to the extent practical that the area selected to determine instrument
background is free of residual radioactive contamination and, that any
radiological sources stored in or near the area are properly shielded to mitigate
any influence to background.
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4.1.5 Set the scaler count time for background determination. The minimum count time
for background determination is 600 seconds or 10 minutes. Longer background
count times may be used.
NOTE
A separate background determination must be determined for each size and
type of pipe that will be surveyed with the detector and data logger pairing.
4.1.6 Install the selected detector into the clean pipe commensurate with the internal
diameter size of the pipe to be surveyed, allow the detector to stabilize and record
the size of the pipe applicable to this efficiency factor determination on
Attachment 1.
4.1.7 Initiate a background count.
4.1.8 Record the background counts on Attachment 1.
1.) Calculate and record the result of the background count.
2.) Establish an acceptable background range of +20%.
4.1.9 Set the scaler count time for source counts. The minimum count time for
efficiency factor determination is 60 seconds or 1 minute. Longer source count
times may be used.
4.1.10 Insert the flexible NIST traceable radiological source into the pipe interior by
placing the source into the interior surfaces of the pipe.
1.) Ensure the exposure surface of the source is secured to the pipe by use of
magnets or other means.
2.) If there is overlap in the area of the source, then ensure (to the extent
practical) the overlap is positioned at the bottom of the pipe.
3.) Mark the source edges within the pipe to ensure the source is positioned in
the same geometry for all subsequent efficiency factor determinations.
NOTE
A separate efficiency factor determination must be determined for each size of
pipe that will be surveyed with the detector and data logger pairing.
Efficiencies determined for larger piping diameters may be utilized for piping
of a smaller diameter and construction material.
4.1.11 Initiate source counts at each of the following nine positions:
1.) Position 1: Detector positioned with the detector crystal centerline -7 inches
back of the source centerline. (See Attachment 5)
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2.) Position 2: Detector positioned with the detector crystal centerline -6 inches
back of the source centerline. (See Attachment 5)
3.) Position 3: Detector positioned with the detector crystal centerline -4 inches
back of the source centerline. (See Attachment 5)
4.) Position 4: Detector positioned with the detector crystal centerline -2 inches
back of the source centerline. (See Attachment 5)
5.) Position 5: Detector positioned with the detector crystal centerline 0 inches
back of the source centerline. (See Attachment 5)
6.) Position 6: Detector positioned with the detector crystal centerline 2 inches
back of the source centerline. (See Attachment 5)
7.) Position 7: Detector positioned with the detector crystal centerline 4 inches
back of the source centerline. (See Attachment 5)
8.) Position 8: Detector positioned with the detector crystal centerline 6 inches
back of the source centerline. (See Attachment 5)
9.) Position 9: Detector positioned with the detector crystal centerline 7 inches
back of the source centerline. (See Attachment 5)
4.1.12 Record the source counts on Attachment 1.
1.) Divide the gross counts by the count time to derive gross cpm.
2.) Subtract the mean background count from each gross cpm value to derive
net cpm.
4.1.13 Calculate the mean net cpm and the standard deviation (σ) for the seven
background corrected source counts (net cpm for positions 2 through 8),
determine a +2σ response range, and record this information on Attachment 1.
NOTE
The mean source count is recorded in units of cpm. The Surface Emission
Rate (SER) of a source is typically presented in units of activity. To calculate
the efficiency factor, the SER units must be converted to units of dpm (1 Ci =
3.7E+10 dps = 2.22E+12 dpm). Position 5 may solely be utilized as the
efficiency determination position at the discretion of the FSS Manager.
4.1.14 Ensure the detector and data logger pair have been post-work response checked in
accordance with LC-FS-PR-011, “Operation of the Ludlum 2350-1 Data Logger
and Associated Detectors” (Reference 2.8).
4.1.15 Forward the completed Attachment 1 to the FSS Supervisor for approval.
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Pre-Use and Post-Use Operational Response and Background Check 4.2.
4.2.1 Select the detector and data logger pairing, as well as the length of cable to be
used, for the pipe size to be surveyed as documented on Attachment 1. Ensure the
detector and data logger pair have been response checked in accordance with LC-
FS-PR-011, “Operation of the Ludlum 2350-1 Data Logger and Associated
Detectors” (Reference 2.8).
4.2.2 Record the pipe size, instrument/detector type, serial numbers, calibration date,
calibration due date and the detector cable length for the detector and data logger
pairing on Attachment 2, “Daily Pipe Survey Detector Control Form.”
4.2.3 Ensure the parameters settings for the data logger (e.g., voltage, etc.) are set to the
values specified for the primary radionuclide to be surveyed per the certificate of
calibration for the paired detector.
4.2.4 Connect the detector to the data logger using the appropriate cable length with the
data logger de-energized.
NOTE
A background count and a response check will be performed twice per day for
each detector and data logger pairing applicable to each pipe size surveyed,
daily prior to use (Pre-Test) and daily upon completion of surveys (Post-Test).
4.2.5 Set the scaler count time for background determination. The background count
time should be the same as the count time used to determine the acceptable range
for background on Attachment 2 (typically 600 seconds or 10 minutes). Longer
background count times may be used.
4.2.6 At the same location where background was determined for the detector and data
logger pairing as documented on Attachment 2, install the selected detector into
the clean pipe commensurate with the ID size of the pipe to be surveyed and
allow the detector to stabilize.
4.2.7 Initiate one background count.
4.2.8 Record the pre-use background count on Attachment 2.
4.2.9 Verify that the observed pre-use background count is within the +20%
background range established during efficiency factor determination for the
selected detector and pipe ID (documented on Attachments 2 & 6).
1.) If the pre-use background count falls within the established +20%
acceptable background range, then the result of the single count is used as BR
for the detector and no additional background counts are required.
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2.) If the pre-use background count falls outside of the established +20%
acceptable background range, then initiate three additional background
counts.
3.) If the mean of the three additional background count results fall within the
established +20% background range, then record the mean value as BR for
the detector and continue with the pre-use operational response check.
4.) If the mean value falls outside the established +20% acceptable background
range, then discontinue the pre-use operational response check and
investigate the reasons for the change in background.
5.) Note the results of recounts, investigations and conclusions in the
“Comments” section on Attachment 2.
4.2.10 Using the value established for pre-use background (BR), calculate the Minimum
Detectable Count Rate (MDCR) for the detector using the following equation:
s
b
s
sR
static t
t
ttB
MDCR
)1(29.33
Where: MDCRstatic = Minimum Detectable Count Rate (cpm)
BR = Background Count Rate (cpm)
tb = Background Count Time (min)
ts = Sample Count Time (initially assumed to be 1 min)
4.2.11 Record the MDCR on Attachment 2.
4.2.12 At the completion of the FSS performed in accordance with section 4.3, repeat
steps 4.2.5 through 4.2.9 for the post-use background check and record the results
on Attachment 2.
NOTE
If a detector/data logger pairing fails a post-use source response check, then
notify the FSS Manager. An assessment must be made to determine the
validity of the data acquired by that detector/data logger pairing and whether
or not the data acquired may be reported as FSS data or if the survey must be
repeated.
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NOTE
CsI detectors may become saturated when exposed to high activity. If a CsI
detector has become saturated during the performance of a survey, then a
delay time may be necessary to allow the luminescence characteristic to return
to ground state. In this case, the FSS Manager may authorize a delay in
performing the post use response check until the beginning of the next daily
shift.
4.2.13 Following completion of the post-use background check in accordance with the
previous step, perform a post-use source check in accordance with LC-FS-PR-
011, “Operation of the Ludlum 2350-1 Data Logger and Associated Detectors”
(Reference 2.8).
4.2.14 Forward the completed Attachment 2 to the FSS Supervisor for approval.
Acquiring FSS Data in Pipe Interiors with NaI/CsI Detectors 4.3.
NOTE
The process of collecting data in pipe interiors assumes that a valid efficiency
factor has been determined for the detector and data logger pairing in
accordance with section 4.1 and a satisfactory pre-use response and
background check has been performed in accordance with section 4.2. If an
efficiency is not available for the size of piping to be surveyed, efficiencies
from larger diameter piping of the same construction may be used.
4.3.1 Record the date, time, location, elevation, a description of the access point to the
pipe, the system, pipe size, pipe identification # (if available), instrument/detector
type, serial numbers, calibration date, calibration due date and the detector cable
length for the detector and data logger pairing on Attachment 3, “Pipe Interior
Radiological Survey Form.”
4.3.2 Examine the overall mechanical condition and operability of the detector/data
logger assembly.
4.3.3 Ensure that the parameters settings for the data logger are set to the values
specified for the primary radionuclide to be surveyed per the certificate of
calibration for the paired detector (as applicable).
4.3.4 Initially set the scaler count time to 60 seconds (1 minute).
NOTE
Notify the FSS Supervisor if the sample count time (ts) is adjusted to achieve
an acceptable Minimum Detectable Concentration (MDC). Sample count
times greater than 10 minutes shall not be used without the approval of the
FSS Manager.
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4.3.5 Using the MDCR established for the detector in step 4.2.10 and the efficiency
factor from step 4.1.13, calculate the MDC for the detector using the following
equation:
MDC= MDCREfficiency Factor⁄
NOTE
The MDC is reported in units of dpm per foot of pipe. In order to compare the
MDC to the action level for buried pipe, the MDC must be converted to units
of dpm/100cm2 (buried pipe). The conforming source has an active surface
area of 3050 cm2, which will be used for all piping greater than 13 inches in
diameter. For 10 inch piping, use 2432 cm2, which is the surface area of one
foot of 10 inch piping. If the field of view is increased using means such as
detector vertical position, the area utilized for conversion may be altered with
approval of the FSS Manager.
1.) Ensure that the MDC calculated is lower than the action levels and/or
DCGL applicable to the pipe to be surveyed.
2.) If the MDC is not sufficient, then adjust the sample count time (ts) in step
4.2.10 as necessary to produce a MDCR which will result in an acceptable
MDC.
3.) If the sample count time (ts) was adjusted to achieve an acceptable MDC,
then set the scaler to the new required count time.
4.3.6 Record the MDC and the sample count time (ts) on Attachment 3.
NOTE
Typically, the optimum start position is with the detector inserted completely
to the end of the pipe to be surveyed with the end of the detector housing flush
with the end of the pipe or butted up against the limiting obstruction (i.e., the
bend or obstruction that prevents further travel into the pipe from the opening
or water). In almost all cases, it is preferable to survey from the maximum
extended position back toward the surveyor. This is not always possible in all
configuration scenarios and adjustments may be made as necessary.
4.3.7 Determine a start location for the survey and mark the position on the
measurement tape as position “zero.”
4.3.8 Initiate a scaler count for the sample count time (ts). This may be performed
utilizing the recycle function of the 2350-1 and observing when the scaler counts
initiate in the first section of piping to be surveyed.
1.) Record the gross counts in the appropriate column on Attachment 3.
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2.) Divide the gross counts by the count time to derive the gross measurement
activity in cpm and record in the appropriate column on Attachment 3.
3.) Subtract the daily background cpm from the gross measurement to obtain
net measurement activity and record in the appropriate column on
Attachment 3.
4.) Divide the net measurement activity in cpm by the efficiency factor to
convert the net measurement activity to units of dpm and record in the
appropriate column on Attachment 3.
5.) Calculate the “Activity/Area” in units of dpm/100cm2 for the measurement
and record in the appropriate column on Attachment 3 using the following
equation:
𝐴𝑑𝑝𝑚100𝑐𝑚2⁄
=
(
(dpm)
(𝐴𝑒𝑓𝑓
100⁄ )
)
Where: A dpm/100cm2 = Activity per Area in units of dpm/100cm
2
dpm = Net measurement activity in units of dpm (from step
4.3.8 (3)
Aeff = Effective Area of the Measurement in m2 (3050 cm
2
for all piping greater than 13 inches in diameter.
For 10 inch piping, use 2432 cm2)
NOTE
The efficiency factors are based on a “worst case” geometry of the bottom of
the piping and distance from source to detector assuming a survey in one foot
increments.
4.3.9 Record the increment frequency on Attachment 3.
4.3.10 Retract or advance the detector as applicable to position “one” and repeat step
4.3.8.
4.3.11 Retract or advance the detector at the required increments and take a measurement
at each location until the survey of the pipe length is completed. Record the
locations and results in the appropriate columns on Attachment 3.
NOTE
If a survey measurement taken on the interior of a buried pipe indicates
radiological concentrations in excess of the applicable DCGL, then notify the
FSS Manager.
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4.3.12 Compare each measurement to the DCGLs established for each type of pipe
(DCGLs for buried pipe types are presented in Attachment 4).
4.3.13 Remove the detector from the pipe when the survey has been completed, or when
an obstruction is present that prevents further travel of the detector through the
pipe. Denote the date and time of survey completion on Attachment 3.
1.) Wipe the cables and detector using a damp rag during extraction.
2.) Examine the overall mechanical condition and operability of the
detector/data logger assembly.
3.) Record the total length of pipe surveyed and the total number of bends
encountered during the survey on Attachment 3.
4.) Denote any unexpected conditions encountered during the survey of the pipe
on Attachment 3. Items to denote include but are not limited to:
Pipe configurations contrary to system drawings
Standing or running liquid in the pipe
Unanticipated obstructions
Indications that the pipe integrity has been compromised
5.) Denote whether the equipment worked properly and as expected. If
problems were encountered with the equipment, then record on
Attachment 3.
6.) Summarize the radiological conditions observed inside the pipe, including
average radiological results and any location(s) encountered which exceed
the Operational DCGLs.
4.3.14 Denote completion of the survey by the signature of all persons involved in
obtaining measurements and forward the completed Attachment 3 to the FSS
Supervisor for review.
4.3.15 Following completion of the last survey using a particular detector, or at the end
of a work shift, perform a post-use source check in accordance with LC-FS-PR-
011, “Operation of the Ludlum 2350-1 Data Logger and Associated Detectors”
(Reference 2.8).
4.3.16 Forward all forms to the FSS Supervisor for data validation and data assessment
in accordance with LC-FS-PR-008, “Final Status Survey Data Assessment”
(Reference 2.6).
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5. ATTACHMENTS
Attachment 1, Pipe Detector Efficiency Determination 5.1.
Attachment 2, Daily Pipe Survey Detector Control Form 5.2.
Attachment 3, Pipe Interior Radiological Survey Form 5.3.
Attachment 4, DCGLs for FSS of Buried Pipe 5.4.
Attachment 5, Pipe Source Efficiency Positions 5.5.
Attachment 6, Example of Source Efficiency and MDCStatic 5.6.
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Attachment 1 - Pipe Detector Efficiency Determination
Detector Type: Serial No.: Cal Date: Cal Due Date:
Data Logger Type: Data Logger Serial No.: Cal Date: Cal Due Date:
Pipe Size: Cable Length: Background Location:
BACKGROUND DETERMINATION
Count Time (tb)
(minutes)
counts cpm
Mean Background cpm (BR) Mean Background
+20%
cpm Mean Background -20% cpm
EFFICIENCY FACTOR DETERMINATION
Source information Isotope: Serial No: Activity
Location
#
Count Time
(min)
Gross
Counts
Gross cpm Net cpm
1
2
3
4
5
6
7
8
9
Efficiency Factor Determination
Mean
Net cpm
Standard Deviation +2σ value -2σ value Source SER
(dpm)
Efficiency Factor
(Mean Net cpm/dpm)
Performed by:
Date:
Approved by:
Date:
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Attachment 2 - Daily Pipe Survey Detector Control Form
PRE-WORK Date:____________ Time:____________
Detector Type: Serial No.: Cal Date: Cal Due Date:
Data Logger Type: Data Logger Serial No.: Cal Date: Cal Due Date:
Pipe Size: Cable Length: Background Location:
PRE-WORK BACKGROUND CHECK Acceptable Background Range (from Attachment 1) +20% cpm -20% cpm
Initial Background Count Additional Background Counts (if necessary)
Count # Count Time (tb)
(min) counts cpm (BR)
Count #
Count Time (tb)
(min) counts cpm (BR)
Initial 1 1. Is pre-work background within the
acceptable range? Yes No If no, initiate three additional
background counts) 2
3 2. Is mean pre-work background within the
acceptable range? Yes No (If no, stop and investigate reasons
for change in background) Mean Background (BR)
MINIMUM DETECTABLE COUNT RATE (MDCR):
s
b
s
sR
static t
t
ttB
MDCR
)1(29.33
Comments:
BR = ________cpm ts = ________min tb = ________min MDCRstatic = ________cpm (ts will initially be set to 1 minute)
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Attachment 2 - Daily Pipe Survey Detector Control Form
POST-WORK Date:____________ Time:____________
POST-WORK BACKGROUND CHECK Acceptable Background Range (from Attachment 1) +20% cpm -20% cpm
Initial Background Count Additional Background Counts (if necessary)
Count # Count Time (tb)
(min) counts cpm (BR)
Count #
Count Time (tb)
(min) counts cpm (BR)
Initial 1 1. Is post-work background within the
acceptable range? Yes No If no, initiate three additional
background counts) 2
3 2. Is mean post-work background within the
acceptable range?
Yes No (If no, stop and investigate reasons
for change in background) Mean Background (BR)
Comments:
Detector/Data Logger Assembly Physical Inspection: Satisfactory Unsatisfactory Technician: __________________ Date: _______ Time: ______
Pre-Work Detector Background Determination: Satisfactory Unsatisfactory Technician: __________________ Date: _______ Time: ______
Pre-Work Instrument Response Check Satisfactory Unsatisfactory Technician: __________________ Date: _______ Time: ______
Post-Work Detector Background Determination: Satisfactory Unsatisfactory Technician: __________________ Date: _______ Time: ______
Post-Work Instrument Response Check Satisfactory Unsatisfactory Technician: __________________ Date: _______ Time: ______
Approved by:
Date:
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Attachment 3 - Pipe Interior Radiological Survey Form (Page 1)
Date: Time:
Survey
Unit:
Access Point Area:
System: Pipe Diameter: Pipe #:
Detector: Detector ID #:
Cal Date: Cal Due Date:
Data Logger: Data Logger ID #:
Cal Date: Cal Due Date:
Cable Length: Pre Use:( Sat / Unsat ) Post Use:( Sat / Unsat )
MDCRstatic cpm (taken from Attachment 2)
Efficiency Factor for Pipe Diameter (taken from Attachment 1)
Effective
Area (cm2)
Background (taken
from Attachment 2):
MDCstatic dpm/100cm2 Sample Count Time (ts) min
Is the MDCstatic acceptable? Yes No (if no, adjust sample count time and recalculate MDCRstatic)
Comments:
Pipe Interior Radiological Survey
Radiological Survey Commenced: Date: ______________ Time: _______________
Radiological Survey Increment Frequency: One measurement for every ____ feet of pipe surveyed
Position
#
Feet into
Pipe from
Opening
Sample
Count Time
(ts)
Gross
Counts
Net
cpm dpm
Effective
Area
Activity/
Area
(min) (cm2) (dpm/100cm2)
Zero
1
2
3
4
5
6
7
8
9
10
11
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Attachment 3 - Pipe Interior Radiological Survey Form
Position
#
Feet into
Pipe from
Opening
Sample
Count Time
(ts)
Gross
Counts
Net
cpm dpm
Effective
Area
Activity/
Area
(min) (cm2) (dpm/100cm2)
Page ___ of ___
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Attachment 3 - Pipe Interior Radiological Survey Form
Pipe Interior Radiological Survey Log
Date Time Comment Initial
Page ___ of ___
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Attachment 3 - Pipe Interior Radiological Survey Form
Pipe Interior Survey Completion
Radiological Survey Completed: Date ____________ Time: ____________
Length of Pipe Surveyed and the Number of Bends
Unexpected Conditions Encountered (Specify any obstructions encountered or other results that may impact
future work):
Did the equipment work properly? Yes No (if “no”, explain below)
Summary of Radiological Conditions (include average radiological results and any hot spot location(s)
encountered):
Survey Completed By: (Print Name) (Signature) (Date & Time)
(Print Name) (Signature) (Date & Time)
(Print Name) (Signature) (Date & Time)
Survey Reviewed By: (Print Name) (Signature) (Date & Time)
Page ___ of ___
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Attachment 4 - DCGLs for FSS of Buried Pipe
Buried Piping DCGL Adjustments for ROC Mixture
Cs-137 Adjustment for Sr-90
Utilizing Equation 4-1 from MARSSIM:
𝐷𝐶𝐺𝐿𝐶𝑠,𝑚𝑜𝑑 = 𝐷𝐶𝐺𝐿𝐶𝑠 ∗𝐷𝐶𝐺𝐿𝑆𝑟
[(𝐶𝑆𝑟𝐶𝐶𝑠) ∗ 𝐷𝐶𝐺𝐿𝐶𝑠] + 𝐷𝐶𝐺𝐿𝑆𝑟
And given from Tables 4 and 12 of LC-FS-TSD-002, Rev. 2:
For Circulating Water Discharge Pipe:
Circulating Water Discharge Base Case and Operational
DCGLs (dpm/100cm2)
ROC DCGLBC DCGLOps
Cs-137 3.30E+05 6.94E+04
Sr-90 7.55E+05 1.58E+05
For Remainder Buried Pipe Group:
Buried Pipe Group Base Case and Operational DCGLs
(dpm/100cm2)
ROC DCGLBC DCGLOps
Cs-137 3.18E+05 6.68E+04
Sr-90 5.16E+05 1.08E+05
RS-TD-31319-001 Rev. 5 states in Table 40 a Sr-90/Cs-137 ratio of 0.502 to 1.
This results in the following DCGLs for Cs-137
Modified Cs-137 DCGLOps Accounting for Sr-90 (dpm/100cm2)
DCGL Buried Pipe Group Circulating Water
Discharge Pipe
DCGLBC 2.42864E+05 2.70621E+05
DCGLOps 5.0973E+04 5.6862E+04
Utilizing the modified DCGLs for Cs-137, equation 4-4 from MARSSIM is utilized:
𝐺𝑟𝑜𝑠𝑠 𝐴𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝐷𝐶𝐺𝐿 =1
(𝑓1
𝐷𝐶𝐺𝐿1+
𝑓2𝐷𝐶𝐺𝐿2
+. . .𝑓𝑛
𝐷𝐶𝐺𝐿𝑛)
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For LACBWR, this equation for gamma emitters becomes:
𝐺𝑟𝑜𝑠𝑠 𝐴𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝐷𝐶𝐺𝐿 =1
(𝑓𝐶𝑜−60
𝐷𝐶𝐺𝐿𝐶𝑜−60+
𝑓𝐶𝑠−137𝐷𝐶𝐺𝐿𝐶𝑠−137
+𝑓𝐸𝑢−152
𝐷𝐶𝐺𝐿𝐸𝑢−152+
𝑓𝐸𝑢−154𝐷𝐶𝐺𝐿𝐸𝑢−154
)
Utilizing Table 42 from RS-TD-31319-001 Rev. 5, the equation becomes:
𝐺𝑟𝑜𝑠𝑠 𝐴𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝐷𝐶𝐺𝐿 =1
(0.0714
𝐷𝐶𝐺𝐿𝐶𝑜−60+
0.919𝐷𝐶𝐺𝐿𝐶𝑠−137
+0.00609
𝐷𝐶𝐺𝐿𝐸𝑢−152+
0.00311𝐷𝐶𝐺𝐿𝐸𝑢−154
)
Utilizing the following gamma emitting DCGLBC from Table 4 of LC-FS-TSD-002, Rev. 2:
ROC Buried Pipe Group
(dpm/100cm2)
Circulating Water Discharge
(dpm/100cm2)
Co-60 7.50E+04 7.75E+04
Cs-137 2.42864E+05 2.70621E+05
Eu-152 1.64E+05 1.67E+05
Eu-154 1.52E+05 1.56E+05
Utilizing the following gamma emitting DCGLOps from Table 12 of LC-FS-TSD-002, Rev. 2:
ROC Buried Pipe Group
(dpm/100cm2)
Circulating Water Discharge
(dpm/100cm2)
Co-60 1.57E+04 1.63E+04
Cs-137 5.0973E+04 5.6862E+04
Eu-152 3.44E+04 3.51E+04
Eu-154 3.20E+04 3.27E+04
The following can then be calculated:
Gross Gamma DCGLs (dpm/100cm2)
DCGL Buried Pipe Group Circulating Water
Discharge Pipe
DCGLBC 2.08611E+05 2.28645E+05
DCGLOps 4.3761E+04 4.8225E+04
Cs-137 was not adjusted for the 0.8512 emission rate due to the calibration source being composed of Cs-137.
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Attachment 5 - Pipe Source Efficiency Positions
Illustration of Source Positions for Efficiency Determination
1 2 3 4 5 6 7 8 9 10 11 12
Flexible Conforming Source
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Attachment 6 - Example of Source Efficiency and MDCStatic
60" Steel Pipe
Small Cart - 5.5" verticle from pipe base to center of detector
Distance From Center of Source -7 -6 -4 -2 0 2 4 6 7
Background Counts Per Minute 3632
Gross Counts Per Minute 26848 28333 30935 33098 35198 33747 31671 27987 23874
Net Counts Per Minute 23216 24701 27303 29466 31566 30115 28039 24355 20242
Percentage of Center Response 0.735474878 0.782519166 0.864949629 0.933472724 1 0.95403282 0.888265856 0.771558005 0.641259583
Average (12") 27935
Background Count Time 10 Efficiency 0.002873971
Sample Count Time 1
Background CPM 3632
MDCR 210.9529858
MDC (dpm) 73401.21791
MDC (dpm/100cm2) 2406.597309
0
5000
10000
15000
20000
25000
30000
35000
-8 -6 -4 -2 0 2 4 6 8
Ne
t cp
m
Distance from Center of Source
60" Steel Pipe