ML26027A175
| ML26027A175 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/08/2024 |
| From: | Yetter R Energy Solutions, Omaha Public Power District |
| To: | Division of Decommissioning, Uranium Recovery and Waste Programs |
| Shared Package | |
| ML26027A165 | List: |
| References | |
| EPID L-2025-LLN-0012 FCSD-RA-LT-308, Rev 2 | |
| Download: ML26027A175 (0) | |
Text
FCSD-RA-LT-308 Electronic documents, once printed, are uncontrolled and may become outdated.
Refer to the Intranet or the Document Control authority for the correct revision.
Radiation Surveys with Pipe Detectors Revision 2 Revision By:
Robert Yetter III, LT/FSS QA Specialist / PM Date Reviewed By:
Mitchell Uz, LT/FSS Lead Specialist Date Reviewed By:
Dan Whisler, FCS Manager Radiation Protection and Chemistry Date Approved By: ________________________________________________
Bill Bishop, LT/FSS Manager Date Non-Proprietary New Proprietary Title Change Restricted Information Revision Safeguards Information Rewrite Sensitive Security Information Cancellation Effective Date:
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 2 of 25 RECORD OF REVISIONS Revision Revision Title Description and Reason for Change 0
Initial issue.
1 Revise source check criteria.
2 4.3.7: Added discussion on methods of ambient background collection.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 3 of 25 Table of Contents 1
PURPOSE AND SCOPE..................................................................................................... 4 1.1 Purpose...................................................................................................................... 4 1.2 Scope.......................................................................................................................... 4 2
REFERENCES..................................................................................................................... 4 2.1 Regulatory Requirements....................................................................................... 4 2.2 Procedures................................................................................................................ 4 3
GENERAL............................................................................................................................ 4 3.1 Definitions and Acronyms....................................................................................... 4 3.2 Responsibilities......................................................................................................... 5 3.3 Precautions, Limitations, and Prerequisites.......................................................... 7 3.4 Records.................................................................................................................... 10 4
REQUIREMENTS AND GUIDANCE............................................................................ 10 4.1 Efficiency Factor Determination and Response Check Determination............ 10 4.2 Pre-Use and Post-Use Operational Response Check.......................................... 15 4.3 Acquiring Data in Pipe and Penetration Interiors.............................................. 18 5
ATTACHMENTS.............................................................................................................. 24 6
FORMS............................................................................................................................... 24
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 4 of 25 1
PURPOSE AND SCOPE 1.1 Purpose The purpose of this procedure is to describe the approach that will be used at the Fort Calhoun Station (FCS) Decommissioning Project to assess the radiological conditions of the interior surfaces of pipe and penetrations using sodium iodide (NaI) and cesium iodide (CsI) detectors.
1.2 Scope This procedure implements the requirements of applicable U.S. Nuclear Regulatory Commission (NRC) regulations and guidance documents; specifically, NUREG-1757, Volume 2, Revision 1, Consolidated Decommissioning Guidance
- Characterization, Survey, and Determination of Radiological Criteria (Reference 2.1.1) and NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) (Reference 2.1.2).
This procedure applies to all personnel designing and implementing radiological surveys of the interior surfaces of pipes and penetrations.
2 REFERENCES 2.1 Regulatory Requirements 2.1.1 NUREG-1757, Volume 2, Revision 1, Consolidated Decommissioning Guidance - Characterization, Survey, and Determination of Radiological Criteria 2.1.2 NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual 2.2 Procedures 2.2.1 FCSD-RA-LT-100, Quality Assurance Project Plan for the License Termination Plan Development, Site Characterization and Final Status Survey Projects at Fort Calhoun Station 2.2.2 EPND-RM-100, Record Management Program 2.2.3 EPND-RM-101, Records Creation, Index, and Transmittal Process 2.2.4 FC-SRRS, SRRS Process 3
GENERAL 3.1 Definitions Calibration - The adjustment or determination of an instruments response relative to a standard or series of conventional true values.
Certification - The use of a derived standard to determine an exposure rate, activity, or other value to the specified or required degree of accuracy.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 5 of 25 Check Source - A radioactive source, not necessarily calibrated, that is used to confirm the continuing satisfactory operation of an instrument.
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.
Performance Test or Response Check - A procedure whereby an instrument or a component is evaluated against accepted criteria for continuing satisfactory operation and use.
3.2 Acronyms and Initialisms CsI cesium iodide DCGL derived concentration guideline level FCS Fort Calhoun Station FSS final status survey GPS Global Positioning System ID internal diameter MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC minimum detectable concentration MDCR minimum detectable count rate NaI sodium iodide NIST National Institute of Standards and Technology NRC U.S. Nuclear Regulatory Commission QA quality assurance QAPP quality assurance project plan RE radiological engineer SER surface emission rate 3.3 Responsibilities 3.3.1 LT/FSS Manager Provides technical oversight and administration of this procedure.
Reviews and approves all sample plans.
3.3.2 Director FCS Decommissioning Project, or designee, Ensures any necessary decontamination activities in the pipes and penetrations are complete.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 6 of 25 Provides physical access to pipe and penetration interior surfaces as required.
3.3.3 LT/FSS Specialist or Radiological Engineer (RE)
Provides direction for pipe and penetration access and decontamination requirements.
Prepares sample plans.
Ensures radiological surveys are conducted in accordance with approved sample plans, procedures, and work instructions.
Provides technical direction and guidance to field survey activities.
3.3.4 LT/FSS Supervisor Determines the adequacy of pipe and penetration access.
Controls and implements the sample plan instructions during field activities.
Ensures all necessary instrumentation and other equipment is available to support survey activities.
3.3.5 LT/FSS Instrumentation Specialist Ensures the calibration of pipe and penetration survey instrumentation.
Maintains the equipment for pipe and penetration surveys in readiness condition.
Performs instrument efficiency evaluations and response checks.
Provides technical guidance for usage of instrumentation and detector packages.
3.3.6 Survey Mapping/CAD/GIS Specialist Prepares survey maps, layout diagrams, composite view drawings and other graphics as necessary to support survey design and reporting.
Interacts with the LT/FSS Specialist regarding the preparation of maps, diagrams, and other graphics which present survey units and sample or measurement locations.
3.3.7 LT/FSS Document Control Specialist Maintains an index of pending, active, and closed sample plans and assigns storage locations.
Ensures that sample plans are properly labeled, stored, and controlled per EPND-RM-100, Record Management Program (Reference 2.2.2), EPND-RM-101, Records Creation, Index, and Transmittal Process (Reference 2.2.3), FC-SRRS, SRRS Process (Reference 2.2.4), and FCSD-RA-LT-100, Quality Assurance Project Plan for the
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 7 of 25 License Termination Plan Development, Site Characterization and Final Status Survey Projects at Fort Calhoun Station (QAPP)
(Reference 2.2.1).
Serves as department records custodian per References 2.2.2, 2.2.3, and 2.2.4.
3.3.8 LT/FSS Technician Obtains and documents survey measurements in accordance with the sample plan instructions.
Ensures that all activities, actions, observations, and obstructions that are encountered during the performance of the required surveys are documented on a field log.
3.4 Precautions, Limitations, and Prerequisites 3.4.1 Precautions A. Documents and databases containing radiological survey data and survey records are quality assurance (QA) records when complete.
Positive control of these records shall be maintained until such time that they are forwarded to Records Management.
B. When documenting survey information, all personnel shall ensure that all QA records are of good quality and legible. Legibility is determined to be readable and reproducible.
C. Do not use any instrument if improper operation is suspected.
D. Ensure the length of the cable between the detector and data logger does not exceed the maximum cable length used during the calibration.
E. 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.
F. Whenever possible, a detector should be calibrated at the same time as the data logger to which it is paired.
G. Detectors that fall outside the accepted criteria shall be tagged Out of Service and segregated for further evaluation. Do not use a detector or data logger with an Out of Service tag attached.
H. When there is a potential for thermal shock, ensure a protective insulator with end cap is installed on the detectors during survey operations to minimize damage from shock and thermal changes. The detector crystal may fracture if the temperature increases or decreases rapidly.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 8 of 25 I. 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.
J. Do not use liquid decontamination solutions on exposed electrically energized equipment.
K. Do not insert radiological detectors into pipes or penetrations where video shows significant standing water, or where significant physical interferences exist that may damage the detector.
3.4.2 Limitations A. All forms described in this procedure may be generated electronically.
If electronic forms are used, the physical layout of the form may be modified provided the intent described in this procedure is not changed.
B. Detector parameters are determined during calibration and shall not be altered during the field operation of the equipment.
C. 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 jig, 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 jig),
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 of this procedure.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 9 of 25 3.4.3 Prerequisites A. A sample plan may be prepared for individual runs of piping and penetrations or groupings of pipes and penetrations based on classification, location, or applicable survey unit.
B. The equipment and services necessary to perform radiological surveys of pipe and penetration interior surfaces may include:
miniature video camera and lighting video console with recording capabilities appropriate length cables and sleeving fiber push/pull rods, fish tape, and measuring tape appropriately sized NaI/CsI radiological detectors radiological data logger (single channel analyzer) field communications equipment vacuum flexible radiological sources and/or point sources appropriately sized pipe test jig C. Decommissioning activities having the potential to contaminate the interior surface of the pipes and penetrations to be surveyed must be completed prior to the initiation of the survey.
D. Prior to inserting a radiological detector into a pipe or penetration, it may be necessary to ensure by remote video that the pipe is free of obstructions and is as dry as possible.
E. Instruments and detectors shall be inspected daily for mechanical damage prior to and following use. The physical inspections shall be documented on FCSD-RA-LT-308-F-03, Pipe Interior Radiological Survey Form.
F. Prior to using any survey instrument, the current calibration must be verified.
G. The efficiency factor for each detector and data logger pairing used for radiological surveys shall be determined in accordance with Section 4.1 of this procedure upon receipt after calibration, as directed by the cognizant LT/FSS Specialist, or following any repair or maintenance.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 10 of 25 H. A response check will be performed daily, prior to use (Pre-Test) and upon completion of surveys (Post-Test), in accordance with Section 4.2 of this procedure for each detector and data logger pairing.
3.5 Records 3.5.1 Records generated by this procedure are listed below and shall be processed per References 2.2.2, 2.2.3, and 2.2.4.
A. FCSD-RA-LT-308-F-01, Pipe Detector Efficiency Determination B. FCSD-RA-LT-308-F-02, Daily Pipe Survey Detector Control Form C. FCSD-RA-LT-308-F-03, Pipe Interior Radiological Survey Form D. FCSD-RA-LT-308-F-04, Pipe Detector Response Determination Form 4
REQUIREMENTS AND GUIDANCE 4.1 Efficiency Factor Determination and Response Check Determination i
NOTE i
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 300 feet.
4.1.1 Select the detector and data logger pairing, as well as the length of cable to be used.
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 FCSD-RA-LT-308-F-01, Pipe Detector Efficiency Determination.
4.1.3 Ensure that the parameters settings for the data logger (e.g., voltage) are set to the values specified 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.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 11 of 25 i
NOTE i
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 on background.
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.
i NOTE i
A separate background determination must be determined for each size of pipe that will be surveyed with the detector and data logger pairing.
i NOTE i
If a pipe test jig is not available for a pipe diameter (mostly applicable to larger pipe internal diameter [ID] greater than 12 inches), then the efficiency determination can be performed by substituting a certified National Institute of Standards and Technology (NIST) traceable point source of acceptable activity for the flexible NIST traceable radiological source and using a table-top jig that models the detector to source distance represented by the ID of the pipe to be surveyed instead of a pipe test jig. Background and efficiency will be determined in the same manner as specified in steps 4.1.6 through 4.1.15.
4.1.6 Install the selected detector into the pipe test jig commensurate with the ID 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 FCSD-RA-LT-308-F-01.
4.1.7 Initiate three background counts, one at each of the following three positions (see Attachment 5.1):
A. Position 1: Detector positioned with the detector crystal centerline back of the pipe jig centerline three inches if the source is greater than eight inches wide. Contact the LT/FSS Manager for direction if using a source less than eight inches wide.
B. Position 2: Detector positioned with the detector crystal centerline positioned at the pipe jig centerline.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 12 of 25 C. Position 3: Detector positioned with the detector crystal centerline in front of the pipe jig centerline the same distance as was used for position 1.
4.1.8 Record the background counts on FCSD-RA-LT-308-F-01.
A. Calculate and record the mean of the three background counts.
B. Establish an acceptable background range of +/-20% from the mean.
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 jig interior by folding the source into the interior surfaces of the jig.
A. Ensure the exposure surface of the source is facing inward and the interior surface of the pipe jig is covered by the source to the extent possible.
B. 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 jig (See.1).
C. Mark the source edges and jig to ensure the source is positioned in the same geometry for all subsequent efficiency factor determinations.
i NOTE i
A separate efficiency factor determination must be determined for each size of pipe that will be surveyed with the detector and data logger pairing.
4.1.11 Initiate ten source counts at each of the following three positions (see.1):
A. Position 1: Detector positioned with the detector crystal centerline back of the pipe jig centerline three inches if the source is greater than eight inches wide. Contact the LT/FSS Manager for direction if using a source less than eight inches wide.
B. Position 2: Detector positioned with the detector crystal centerline positioned at the pipe jig centerline.
C. Position 3: Detector positioned with the detector crystal centerline six inches in front of the pipe jig centerline the same distance as was used for position 1.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 13 of 25 4.1.12 Record the source counts on FCSD-RA-LT-308-F-01.
A. Divide the gross counts by the count time to derive gross cpm.
B. 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 () for the thirty background corrected source counts (net cpm), determine a +/-2 response range, and record this information on FCSD-RA-LT-308-F-01.
i NOTE i
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 2 may solely be utilized as the efficiency determination position at the discretion of the FSS Manager.
4.1.14 Calculate an efficiency factor for the detector and data logger pairing and the detector cable length for the pipe ID commensurate with the size of the source jig by dividing the mean source count (mean net cpm) by the SER of the source and record the efficiency factor on FCSD-RA-LT-308-F-01.
4.1.15 Forward the completed FCSD-RA-LT-308-F-01 to the cognizant LT/FSS Supervisor for approval and proceed with response check determination as applicable.
4.1.16 Prior to placing a detector into service after calibration and efficiency determination, establish response check criteria as detailed in the following steps.
4.1.17 Set the scaler count time to 600 seconds (10 minutes) for background determination.
i NOTE Source response and background checks should be performed in an area where background measurements are expected to remain stable for the duration of the project. The cable length between the detector and instrument should match the cable length used during the calibration and efficiency determination.
i
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 14 of 25 4.1.18 Place the selected detector onto the appropriately sized pipe for the detector to be used.
4.1.19 Energize the detector and allow the detector to stabilize.
4.1.20 Initiate and log three, 10-minute background counts on FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form.
4.1.21 Calculate and record the average of the three background counts. Establish a range of +20% from the average and record this information on FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form.
4.1.22 Set the scaler count time to 60 seconds (1 minute).
4.1.23 Place a gamma emitting check source in a reproducible geometry to the center of the detector end, document the source information on FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form.
4.1.24 Initiate and log (20) one-minute source counts.
4.1.25 Record the source response results on FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form.
4.1.26 Calculate and record the net mean source cpm.
4.1.27 Establish a +20% from the average value and record this information on FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form.
4.1.28 FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form will establish the required averages and accepted ranges for assuring proper operation for each detector.
4.1.29 Transpose parameter data from FCSD-RA-LT-308-F-04 Pipe Detector Response Determination Form to FCSD-RA-LT-308-F-02 Daily Pipe Survey Detector Control Form.
i NOTE The source selected for the response check must be the same isotope as used for the efficiency determination.
i
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 15 of 25 4.2 Pre-Use and Post-Use Operational Response Check 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 FCSD-RA-LT-308-F-01.
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 FCSD-RA-LT-308-F-02, 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 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.
i NOTE i
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 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 FCSD-RA-LT-308-F-01 (typically 600 seconds or 10 minutes). Longer background count times may be used.
i NOTE i
If a table-top jig and point source were used in Section 4.1 to determine efficiency, then the same table-top jig and point source will be used for pre-use and post-use operational response checks in steps 4.2.6 through 4.2.18.
4.2.6 At the same location where background was determined for the detector and data logger pairing as documented on FCSD-RA-LT-308-F-01, install the selected detector into the pipe test jig commensurate with the ID size of the pipe to be surveyed, and allow the detector to stabilize.
4.2.7 Initiate one background count with the detector positioned with the detector crystal centerline positioned at the pipe jig centerline. (See.1).
4.2.8 Record the pre-use background count on FCSD-RA-LT-308-F-02.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 16 of 25 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 FCSD-RA-LT-308-F-01).
A. 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.
B. If the pre-use background count falls outside of the established +/-20%
acceptable background range, then initiate three additional background counts.
C. 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.
D. 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.
E. Note the results of recounts, investigations, and conclusions in the Comments section on FCSD-RA-LT-308-F-02.
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 s
R static t
t t
t B
)
1(
29
.3 3
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 FCSD-RA-LT-308-F-02.
4.2.12 Set the scaler count time for source counts. The source count time should be the same as the count time used to determine the acceptable range for source counts on Attachment 1 (typically 60 seconds or 1 minute). Longer source count times may be used.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 17 of 25 i
NOTE i
The source used for the daily operational response check must be the same source used for the determination of the efficiency factor in Section 4.1. If that source is not available, a new efficiency factor must be performed in accordance with Section 4.1 using the new source.
i NOTE i
If used to determine efficiency in Section 4.1, then a certified NIST traceable point source of acceptable activity will be substituted for the flexible NIST traceable radiological source to perform the daily operational response checks.
4.2.13 Insert the flexible NIST traceable radiological source into the pipe jig interior by folding the source into the interior surfaces of the jig and ensure the source is positioned in the same geometry as for the determination of the efficiency factor.
4.2.14 Position the detector with the detector crystal centerline positioned at the pipe jig centerline (Position 2 on Attachment 5.1) and allow the detector to stabilize.
4.2.15 Initiate a single source count and record result.
4.2.16 Record the pre-use source response result on FCSD-RA-LT-308-F-02.
A. Divide the gross counts by the count time to derive gross cpm.
B. Subtract the pre-use background (BR) from the gross cpm value to derive net cpm.
C. Verify that the pre-use source response count (net cpm) falls within the established acceptable response range (+/-20%) from step 4.1.27 for the selected source, detector, and pipe ID.
D. If the pre-use source response count (net cpm) falls within the established acceptable response range (+/-20%), then the operational response check is satisfactory E. If the average source response count falls outside of the established acceptable response range (+/-20%), then place the detector out of service.
F. Record the results on FCSD-RA-LT-308-F-02.
4.2.17 At the completion of survey, repeat steps 4.2.5 through 4.2.9 for the post-use background check and record the results on FCSD-RA-LT-308-F-02.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 18 of 25 i
NOTE i
If a detector/data logger pairing fails a post-use source response check, then notify the LT/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 or if the survey must be repeated.
i NOTE i
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 LT/FSS Manager may authorize a delay in performing the post-use response check until the beginning of the next daily shift.
4.2.18 Following completion of the post-use background check in accordance with the previous step, repeat steps 4.2.12 through 4.2.16 for the post-use source response result and record the results on FCSD-RA-LT-308-F-02.
4.2.19 Forward the completed FCSD-RA-LT-308-F-02 to the cognizant LT/FSS Supervisor for approval.
4.3 Acquiring Data in Pipe and Penetration Interiors i
NOTE i
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 check has been performed in accordance with Section 4.2.
4.3.1 Record the date, time, building, 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 FCSD-RA-LT-308-F-03, 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 per the certificate of calibration for the paired detector.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 19 of 25 4.3.4 Initially set the scaler count time to 60 seconds (1 minute).
i NOTE i
Notify the cognizant LT/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 LT/FSS Manager.
4.3.5 Using the MDCR established for the detector in step 4.2.10 and the efficiency factor from step 4.1.14, calculate the MDC for the detector using the following equation:
MDC = MDCR Efficiency Factor i
NOTE i
The MDC is reported in units of dpm per foot of pipe. In order to compare the MDC to the action level for embedded pipe or buried pipe, the MDC must be converted to units of pCi/m2 (embedded pipe or penetrations) or dpm/100cm2 (buried pipe).
A. Ensure that the MDC calculated is lower than the action levels applicable to the pipe or penetration to be surveyed.
B. If the MDC is not sufficient, then adjust the sample count time (ts) in step 4.2.10 as necessary to produce an MDCR which will result in an acceptable MDC.
C. 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 FCSD-RA-LT-308-F-
- 03.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 20 of 25 i
NOTE i
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). 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 fiber rod or fish tape as position zero.
i NOTE i
Typically, background will not be subtracted from measurements taken inside a pipe. If it is determined that the radiological background in or in the general vicinity of the pipe is influenced by external radiological sources, background may be assessed for the survey and the measurements taken inside the pipe may be adjusted for the background contribution. This shall only be performed with the approval of the LT/FSS Manager.
Ambient background assessment methods may include, but are not limited to, using a reference area (area external to the lab with like pipe material and conditions [buried, embedded, etc.]) or developing an average background at the face of the pipe(s) (count times determined by LT/FSS Supervisor or LT/FSS Specialist).
Note that ambient background is separate from the background measurements collected for response checks or efficiency determinations.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 21 of 25 4.3.8 Initiate a scaler count for the sample count time (ts).
A. Record the gross counts in the appropriate column on FCSD-RA-LT-308-F-03.
B. Divide the gross counts by the count time to derive the measurement activity in cpm, and record in the appropriate column on FCSD-RA-LT-308-F-03.
C. Divide the measurement activity in cpm by the efficiency factor to convert the measurement activity to units of dpm, and record in the appropriate column on FCSD-RA-LT-308-F-03.
D. If performing measurements for embedded pipe or penetrations, then calculate the effective detection area in m2 for the measurement, and record in the appropriate column on FCSD-RA-LT-308-F-03 using the following equation:
Aeff = 2 Pipe ID 12
2 x 9.29E-2 Where: Aeff
= Effective Area of the Measurement in m2 Pipe ID
= Internal diameter of the pipe in inches E. If performing measurements for buried pipe, then calculate the effective detection area (Aeff) in cm2 for the measurement by multiplying the result in the previous step by 1.0E+04, and record in the appropriate column on FCSD-RA-LT-308-F-03, then calculate the Activity/Area in units of dpm/100cm2 for the measurement, and record in the appropriate column on FCSD-RA-LT-308-F-03 using the following equation:
=
dpm
100
Where: A dpm/100cm2 = Activity per Area in units of dpm/100cm2 dpm
= Measurement activity in units of dpm (from step 4.3.8 (3)
Aeff
= Effective Area of the Measurement in m2 (from step 4.3.8 (5)
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 22 of 25 F. If performing measurements for embedded pipe or penetrations, then calculate the Activity/Area in units of pCi/m2 for the measurement, and record in the appropriate column on FCSD-RA-LT-308-F-03 using the following equation:
= dpmx4.50E-1 Aeff Where: A pCi/m2 = Activity per Area in units of pCi/m2 dpm
= Measurement activity in units of dpm (from step 4.3.8 (3)
Aeff
= Effective Area of the Measurement in m2 (from step 4.3.8 (4) i NOTE i
The efficiency factors are based on a worst case geometry and distance from source to detector assuming a survey in increments equal to the width of the source utilized for efficiency calibration. Consequently, a survey of a pipe taking a measurement in increments equal to the source width is assumed to represent 100% areal survey coverage of the interior surfaces of the pipe. For surveys of pipe interiors at increments greater than one foot, the measurement conservatively represents the radiological conditions of the pipe equal to one half of the source width on either side of the detector centerline.
4.3.9 Record the increment frequency on FCSD-RA-LT-308-F-03.
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 FCSD-RA-LT-308-F-03.
i NOTE i
If a survey measurement taken on the interior of an embedded pipe, penetration, or buried pipe indicates radiological concentrations in excess of the applicable action levels, then notify an LT/FSS Supervisor.
4.3.12 Compare each measurement to the action levels established for each type of pipe.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 23 of 25 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 FCSD-RA-LT-308-F-03.
A. Wipe the cables and detector using a damp rag during extraction.
B. Examine the overall mechanical condition and operability of the detector/data logger assembly.
C. Record the total length of pipe surveyed and the total number of bends encountered during the survey on FCSD-RA-LT-308-F-03.
D. Denote any unexpected conditions encountered during the survey of the pipe on FCSD-RA-LT-308-F-03. 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 E. Denote whether the equipment worked properly and as expected. If problems were encountered with the equipment, then record on FCSD-RA-LT-308-F-03.
F. Summarize the radiological conditions observed inside the pipe, including average radiological results and any hot spot locations encountered.
4.3.14 Denote completion of the survey by the signature of all persons involved in obtaining measurements and forward the completed FCSD-RA-LT-308-F-03 to the cognizant LT/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 operational response check in accordance with step 4.2.17.
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 Proprietary Information Page 24 of 25 5
ATTACHMENTS 5.1 Pipe Jig Positions 6
FORMS 6.1 FCSD-RA-LT-308-F-01, Pipe Detector Efficiency Determination 6.2 FCSD-RA-LT-308-F-02, Daily Pipe Survey Detector Control Form 6.3 FCSD-RA-LT-308-F-03, Pipe Interior Radiological Survey Form 6.4 FCSD-RA-LT-308-F-04, Pipe Detector Response Determination Form
Radiation Surveys with Pipe Detectors FCSD-RA-LT-308 Revision 2 ATTACHMENT 5.1 PIPE JIG POSITIONS Proprietary Information Page 25 of 25