ML20235S614
| ML20235S614 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 05/15/1987 |
| From: | Mulcahey E POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | |
| Shared Package | |
| ML20235S575 | List: |
| References | |
| PDP-7, NUDOCS 8707210718 | |
| Download: ML20235S614 (16) | |
Text
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NEW YORK POWER AUTHORITY-JAMES A. FITZPATRICK NUCLEAR POWER PLANT RADI0 LOGICAL AND ENVIRONMENTAL SERVICES DEPARTMENT PROCEDURE NO.-: PDP-7 .
1 TITLE: DOSIMETRY SYSTEM CALIBRATION l AND QUALITY CONTROL PROCEDURE 1
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PORC Review No./Date Meeting No. N/A Date 5//o~/77 Approved By: , um -
Resident Manager Approved By: A m 8e Radiological and Environ tal Services Superintendent
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F sw 0W Page No.: 1 1 2 3 4 5 6 7 8 9 10 Rev. No : 2 3 2 2 2 3 3 3 3 3 3 Page No.: 11 12 13 14 Rev. No.: 3 2 3 2 Rev. No. 3 Date 05/87 8707210718 s70626-PDR ADOCK O g3 l
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DOSIMETRY SYSTEM CALIBRATION AND QUALITY CONTROL PROCEDURE Table of Contents l
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1.0 PURPOSE 1 2.0 REQUIREMENTS AND ACCEPTANCE CRITERIA 1 3.0 SPECIAL EQUIPMENT 2 4.0 PREREQUISITES AND PRECAUTIONS 2 5.0 PROCEDURE 3 -
5.1 Independent System Tests 3 5.2 Neutron Dosimetry 5 5.3 In-house TLD Testing Program 6 5.4 UD-807 Extremity TLD Testing 7 5.5 TLD Reader Calibration 7 5.6 New Equipment Acceptance Tests 9 5.7 Routine TLD Testing 10 5.8 TLD Processing QC 11 5.9 REM System Software Quality Control 11
6.0 REFERENCES
12 7.0 ATTACHMENTS 12 Rev. No. 3 Date 05/87 Page i of PDP-7
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PDP-7 DOSIMETRY SYSTEM CALIBRATION AND QUALITY CONTROL PROCEDURE 1.O PURPOSE This procedure is designed to assure that the personnel dosimetry system meets or exceeds current performance re-quirements.
2.0 REQUIREMENTS AND ACCEPTANCE CRITERIA 2.1 Radiation Protectin Manual General requirements of testing, calibration and quality assurance of dosimeters and NVLAP accreditation are given in Chapter 7, Section 7.11.
2.2 In - House Semimonthly Performance Tests Using the performance standard specified in ANSI N 13.11, Criteria for Testing Personnel Dosimetry Performance, the following acceptance criteria and limits apply:
2.2.1 Action Level Tne Action Level is a level which, if exceeded, indicates degraded TLD system performance. If the action level is exceeded, TLD processing shall be terminated and the Dosimetry Supervisor and the Radiological Engineer shall be notified. TLD processing may only be resumed following an evaluation by the Dosimetry Supervisor or the Radiological Engineer and a semimonthly performance test has been successfully completed. The Action Levels for semimonthly testing are:
lBl + S >0.3 for any test.
The value of lBl + S changes by more than 0 2 from the preceeding test, except following maintenance or recalibration of the TLD reader.
2.2.2 Alert Level The Alert Level indicates a potential degradation '
in system performance. If the Alert Level is exceeded, the Dosimetry Supervisor and the Radiological Engineer shall be notified and the potential causes investigated. The Alert Level for semimonthly testing is:
lBl + S >0.15 for three consecutive tests.
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l 3.0 SPECIAL EQUIPMENT 3.1 The dosimetry device used at JAF is the Panasonic Model UD-812AS Thermoluminescent Dosimeter (TLD) which consists of four depleted Lithium Borate (7Li 911B 307 CU) phosphor elements. When inserted into the hanget the following filtering is provided:
Element 1 = - 11 mg/cm2 Element 2 = 56 mg/cm2 Element 3 - 300 mg/cm2 Element 4 = - 1000 mg/cm2 Each dosimeter is identified with a serial number which is punch hole coded into the dosimeter and typed onto the label of the dosimeter.
3.2 The exposure accumulated by the TLD is measured using a Panasonic Model UD-710A TL Badge Reader. ,
3.3 In-house test exposures are made with a Shepard Model 142-10 irradiator and an Eberline depleted uranium slab to test for whole body and skin exposures respectively.
4.0 PREREQUISITES AND PRECAUTIONS 4.1 Observe all standard precautions for handling radioactive materials as outlined in the plant Radiation Protection Manual.
4.2 Record all data pertinent to calibration testing and QC not already documented, as well as the date, time, nature of and reason for any repairs or preventative maintenance in the Dosimetry Maintenance Log Book. The log book shall be maintained by the Dosimetry Supervisor. This log shall be reviewed quarterly by the Radiological Engineer with a line entry in the log.
Rev. No. 2 Date 05/87 Page 2 of PDP-7
- , 'e 5.0 PROCEDURE 5.1 Independent System Tests An independent testing laboratory shall be retained to determine the performance of the TLD system. The following is a description of the program used at JAF.
5.1.1 Test Categories and Test Ranges
.The UD-812AS2 TLD presently being used at JAF is speci-fically designed for use as a high and low energy photon and beta dosimeter. Typically, in a BWR, the type of radiation exposure received by an individual is a mix >
ture of these three radiatiens with the predominant type being high energy photons. Exposure to a pure beta or pure low energy source is highly unlikely. Therefore, the test categories that have been selected are as fol-lows:
Category Description *l II - Accidents, high energy photons (Cs-137 gamma radiation)
IV - High energy photons VI - Photon mixtures (any combination of low energy and high energy photons)
VII- Mixtures, photons and beta particles (any com-bination of Sr-90 aw. Y-90 and high energy photons).
5.1.2 Test Frequency and Requirements '
Minimum testing requirements shall include one complate test per category per year.
- a. At least 15 TLDs shall be irradiated for any given test category. An additional 15 TLDs should be added for each additional reader being tested.
- b. Include at least three additional TLDs to be irradi- l ated to a predetermined exposure (Cs-137) to be used '
as audit badges.
- c. Include a minimum of three TLDs as shipping (back-ground) controls. l
- d. If the exposure interpretation from more than two of the dosimeters irradiated in a given category have to be voided because of problems caused by either the testing laboratory or the processor, statistical analysis of the results of this category shall be Rev No. 2 Date 05/87 Page 3 of PDP-7 i
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g delayed until' replacement dosimeters have been sub-mitted and irradiated and the results reported by the processor to the testing laboratory.
- 5.1.3 UD-812 Test Schedule (whole' body and skin dosimetry)
- a. Each test shall extend over a' period of six months in.
three groupa.
'b. The test TLDs shall be submitted to. the- testing laboratory in three separate ' groups , preferably at two . month intervals. It will not be necessary to withhold shipment of a group pending receipt of the group'previously sent.
- c. Each group shall be returned by the testing labora-tory to the plant within one month from receipt. The audit: dosimeters (irradiated with Cs-137) shall' be identified. .The category of the test dosimeters shall not be divulged to the processor. .-
- d. The TLDs should be read within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> from the date received into the RES Department. The results should be sent out to the testing laboratory within 10 days of the ' receipt of the test batch. The following minimum information shall be included in the report to the testing laboratory:
(1) Receiving date (2) Reading date <
i (3) Deep exposure (blind test TLDs)
(4) Shallow exposure (blind test TLDs) 5.1.4 TLD Selection
- a. A random number generating program shall be used to determine which TLDs are to be shipped for testing.
Since a large number of TLDs are in use or otherwise unavailable for testing, a list of 100 random numbers j within the range of the TLD numbers available is i generated.
- b. Select the TLDs in the order specified by the random number program, skipping only those that are not available at the time of selection. Cross off those numbers not selected from the list.
- c. Anneal the selected TLDs insuring that all elements have less than 10 mrem residual exposure.
- d. Wipe off the TLDs using white Masslinn towel, damp-ened wf ch a solution of 50 percent methanol and 50 Rev. No. 2 Date 05/87 Page 4 of PDP-7 1
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l percent demineralized water. This will remove undetectable contamination that could affect the test results.
- e. Package the TLDs and ship them to the tasting labor-
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atory.
5.1.5 Dissemination of Test Results The testing laboratory shall report the test results for each TLD at the completion of each test. This report shall not be altered or voided and shall be maintained as a plant record.
5.1.6 Evaluation of Test Results The response of the tested TLDs shall be evaluated as soon as the testing laboratory results arrive at the j plant. These evaluations shall be performed in the same i manner as specified in ANSI N13.11. Results of previous tests can be included in the certification letter accom- .
panying future test groups. Test data shall contain no outliers that are not obviously defective TLDs for a test to pass.
5.1.7 Corrective Action The primary purpose for conducting these tests is to provide assurance that the TLD system exceeds the established performance acceptance criteria of ANSI N13 11. In the event that a test does not pass, use of ..
the TLD reader will be suspended until the cause of failure is investigated and any necessary corrective actions have been taken. An additional set of 15 TLDs for each category should be submitted to the testing laboratory for irradiation and used to verify the reader 3 is functioning properly. At this time the results of TLDs used for personnel monitoring that were processed since the last successful reader test should be examitwd to determine if there is a need to make corrections to the data.
5.2 Neutron Dosimetry i
Independent test laboratory results for Neutrak-1:R neutron dosimetry packets are on file in the REM system office, ]j l
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5.3 In-house (Semi-Monthly) TLD Testing Program The Shepard Model 142-10 Calibrator is used to expose TLDs to reproducible deep exposures. The depleted U-235 slab source shall be used to expose TLDs to a reproducible deep and shallow exposure. All test results are submitted to the Radiological Engineer for review and approval. A group (16) of the UD-812 TLDs are irradiated semimonthly, prior to col lecting and reading TLDs from the scheduled-change period.
5.3.1 Irradiate four sets of four TLDs to four different ranges such that the range of expected measurements is adequately tested. Exposures to this group of TLDs should be limited to the protection range of 0.03 rem to 10 rem.
5.3.2 Record date and time, and length of irradiation.
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NOTE: At this time irradiate an additional 50 TLDs to ,
200 mrem for daily testing.
5.3.3 Allow approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for fading prior to reading the TLDs. 1 5.3.4 Record the precleaning sensitivity correction factor in the TLD reader maintenance log book 5.3.5 Clean the render in accordance with the manufacturer's recommendations on preventative maintenance. Allow at least 30 minutes warm-up after cleaning before recording the sensitivity correction factor.
5.3.6 Read and evaluate TLDs using the programs TLDCPT and ]
TLREAD according to vendor supplied instructions. j i
5.3.7 Using the program called "PERCAL" determine the perfor- 1 mance indicators defined in ANSI N13.11 (Pi, B & S). l The results must meet the criteria in ANSI N13.11. If !
lBl + S >0.3 notify the Dosimetry Supervisor before using the reader to determine any record exposures. If 4 lBI + S >0.15, review the two proceeding tests. If the last two tests and the current test have a result of lBl + S >0.15, notify the Dosimetry Supervisor or the ,
Radiological Engineer. ;
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l NOTE: Refer to vendor supplied documentation for specific program operating instructions.
5.3.8 Record the test results (B, S, lBl + S) in the TLD Reader Maintenance log book. Enter these values into the "DOSQC" data base. Monthly generate a new plot cf the last year of data using the ',QCPLOT" program.
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g h 5.3.9 Perform a RUNG test on the data using the "QCEDIT" program.
5.4 'UD-807 Extremity TLD Testing
.A' group of eight UD-807 dosimeters shall be . exposed quarterly to a known radiation source.
- 5. 4.1' Expose eight UD-807 dosimeters in the appropriate hangers . on the . uranium slab such that. four receive exposures of 300 to 400 mrad radiation and the remaining four receive exposures of 1,500 to 1,800 mrad radiation.
5.4.2 Expose eight UD-807 dosimeters in the appropriate hangers on the 142-10 irradiator such that four receive exposures of'300 to 400 mR gamma and the remaining'four receive exposures of 1,500 to 1,800 mR.
5.4.3 Allow approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for fading.
5.4.4- Read the TLDs using TLDCPT. and calculate exposure on UD-807 dosimeters using the current correction factor.
5.4.5 Use PERCAL for performance calculations.
5.4.6 Performance testing shall be conducted in accordance with ANSI N13.11. This test must meet the criteria established in ANSI N13.11 with no outliers to pas s . - '
All outliers from the test batch shall be retired from service. j 5.4.7 If.this test fails, discontinue readirig extremity TLDs (UD-807) until the problem has been identified and- -
corrected as verified by a successful retest. j j
5.4.8 The correction factor may be recalculated from these i results in order to maintain the performance index close 1 to zero.
5.5 TLD Reader Calibration
.5. 5.1 Selection of Calibration Badges Select 50 normal reference TLDs (mean ECF for all elements =
0.95 to 1.05 and all element mean sigma
<6.0%) and 20 accident range reference TLDs (residual dose >10 mrem).
5.5.2 Calibration Source 1 The Shepard Model 142-10 Cs-137 irradiator should be j used to irradiate calibration TLDs.
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NOTE: The high dose TLDs should be the same ones used for previous high dose calibrations.
5.5.3 TLD Irradiation Irradiate 50 calibration TLDs to a dose of approximately 400 mR and another 20 TLDs to a dose of approximately 30R at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> but not greater than seten days prior to reader calibration. Record date of irradiation.
5.5.4 Reader Preparation Clean the TLD reader in accordance with section 6-3 (page 50) of the Panasonic Operating Instruction Manual and leave it in the BADGE SERVICE mode for at least one hour prior to performing a calibration. Insure that the sensitivity correction factor is equal to 1.00 1 0.05.
5.5.5 Photon and Frequency Counter Coefficients
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- a. Load a TLD tray with 25 of the low dose and 10 of the high dose TLDs. Read the TLDs using the programs TLDCPT and TLREAD.
- b. Calculate the average measured dose (M) to the ECF corrected element 4 for each of the two groups of TLDs using the following formula:
n I E4(1)
M = i=1 ._
n Where:
. n = Number of TLDs used for each group.
- c. Calculate a Photon Counter Correction Factor (PCCF) by dividing the low dose (group 1) average measured dose (M) by the delivered dose (D) to those TLDs exposed to approximately 400 mR as follows:
PCCF = M w Dose) j D (Low Dose) {
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- d. Divide the current Photon Counter Conversion Coef- I ficient; (PCCC = parameter SA) by the PCCF and enter !
the new value into the TLD reader parameter 5A.
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- e. Calculate the Frequency Counter Correction Factor (FCCF) by dividing the high dose (group 2) average l measured dose (M) by the delivered dose (D) to those l TLDs irradiated to approximately 30R. ]
FCCF = M (High Dose) l D (High Dose) l I
Rev. No. 3 Date 05/87 Page 8 of PDP-7
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- f. Divide the current Frequency Counter Conversion Coefficient (FCCC = parameter 5B) by the FCCF and enter the new value into the TLD reader parameter 5B.
- g. Verify the new values for the PCCC and the FCCC are correct by reading the remaining TLDs in each group and perform the performance calculations specified in
. ANSI N13.11:using ECF corrected Element 4 values for measured deep dose.
- h. Verify that the calibration is correct by processing a set of TLDs in each normal monitoring category (categories IV, VI, VII) exposed by an independent testing laboratory and performing the ANSI perfor-mance calculations on the results using the program PERCAL.
5.5.6 Recording Resulto
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Record all results on the TLD Reader Calibration form (Figure 1) and attach all of the data sheets to this form. Forward the calibration foral and data to the Radiological Et.gineer for approval before resuming use of the TLD reader. Enter the calibration date and the reason for calibration in the TLD reader maintenance log book.
5.5.7 Frequency of Calibration Since the TLD reader calibration is routinely verified through both in-house testing and annual independent laboratory testing, this calibration need be performed only when:
- a. Repairs are made to the reader that affect the '
calibration.
- b. The reader fails an in-house or independent labora-tory test and the REASON for the failure cannot be deterrained and corrected, 5.6 N_ew Equipment Acceptance Tests 5.6.1 New Desimeter Acceptance Visually inspect each of the new TLDs for defects and insert them into hangers. Irradiate them to approxi-mately 400mR using the Shepard Model 142-10 irradiator (approximately 100 TLDs can be irradiated at one time).
NOTE: Refer to vendor supplied documentation for j detailed program operating instructions.
- a. Using the program called TLDCPT, read the TLDs.
Rev. No. 3 Date 05/87 Page 9 of PDP-7
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- b. Using the program called TLCHCK, verify the TLDs are numbered properly,
5.6.2 New Hanger Acceptance Visually inspect the hangers for defects and install the rubber gaskets. Ensure the spring clips are securely fastened and hinges function properly.
5.7 TLD Checks Prior to placing new TLDs into service, generate at least three element calibration factors for each element and use these factors to generate a Mean Element Calibration factor for each element.
At least annually, generate a new Element Calibration .
factor and Mean Element Calibration factor for the TLDs in service and the reference TLDs.
5.7.1 Irradiate the TLDs to approximately 400mR at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to reading using the Shepard Model 142-10 irradiator. Include fifteen reference TLDs in each irradiation group.
5.7.2 Read the TLDs on the 710A TLD reader using the program called "TLDCPT".
5.7.3 Using the program called "TLECF", generate element calibration factors for each of the TLDs. This program will use the average reading on the appropriate element of the reference TLDs to determine the delivered expo-sure, If initial ECFs are being generated for new TLDs, store all of the ECFs except those for the reference badges. If annual ECFs are being generated, store only those that are within .15 of the previous Mean ECF.
Retest the TLDs that fail this criteria and remove all TLDs from service whose new ECFs fail the second time.
NOTE: Refer to vendor supplied documentation for specific program operating instructions.
5.7.4 After at least three ECFs have been generated and stored (steps 5.7.1 thru 5.7.3), for each element generate a Mean ECF for each element using the program called "TLMECF".
l 5.7.5 Annually or when new elements are put in service, verify l that each of the extremity elements responds to within 30% of the delivered dose by irradiating them in the bandage holders to 100mR on the 142-10 irradiator. Read Rev. No. 3 Date 05/87 Page 10 of PDF-7
. . t them after a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> fade period and remove from service all of those that do not read within 70 to 130 mrem.
5.8 TLD Processing-QC As each batch (up to 500) of TLDs that were used to monitor personnel exposure is read run QC TLDs are also processed.
5.8.1 At the time semimonthly test TLDs are irradiated, a sufficient number of field TLDs (' 50) should also be irradiated to 200 mR for use as run QC badges during processing.
5.8.2 Whenever the TLD reader is being used to determine record exposures run QC badges should be included. If the batch contains 150 or less TLDs 3 run QC TLDs should be added to the batch. If the batch contains greater than 150 TLDs a number of run QC badges equal to 2% of the batch size should be added (e.g. 500 TLD batch X 2%
= 10 run QC TLDs). Theue TLDs should be randomly added .
to the trays of badges to be read.
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5.8.3 When the TLD data is processed by the computer enter the serial number of the run QC badges as the CALIBRATION TLDs. The run calibration factors should be between j 0.70 and 1.30. 1 l
5.8.4 If the TLD reader fails, the test of 5.8.3 above stop processing TLDs and notify the Desimetry Supervisor.
Depending on the cause of the failure the Dosimetry Supervisor may require a review and/or correction of the TLD data generated since the last successful test.
5.9 P_EM System Software Quality Control In order to insure that the software continues to supply accurate, timely information to plant personnel, the following steps will be followed:
5.9.1 Any changes in the sof tware will be initiated using a Program Modification Log (Figure 2) by the Dosimetry Supervisor, Radiological Engineer or the RES Superinten-dent specifically stating the change desired and the objective of the change.
5.9.2 Modified programs will be rested on typical data and the expected extremes of data. Calculations will be veri-fied by hand or by record checks prior ta placing the modified programs in service. A file called " GENERIC" contains raw TLD data that accesses each segment of the dose algoritha for verification of TLD processing program modification verification.
I Rev. No. 3 Date 05/87 Page 11 of PDP-7
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- 4 5.9.3 Final test results, raw test data, any 'essociated printed reports , and the original Program Modification-
~ Log (generated by step 5.9.1) will be kept in the REM system office files.
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I' 6.O REFERENCES 6.1- Background References 6.1.1 ANSI N13. 6' - 1966 (R1972), Practice for Occupational Radiation Exposure Records Systems 6.1.2 ANSI N13.11, Criteria for Testing Personnel Dosimetry.
Performance, 1983 6.1.3 National Voluntary Laboratory Accreditation Program l Dosimetry ' LAP Handbook, U.S. Department of Commerce, '
National Bureau of Standards, 1983 l
'l 6.1.4 RES Department Procedures and Programs (as referenced in ., l this procedure) 6.1.5 Plant Dosimetry Procedures (PDPs as referenced in this procedure) 6.2 Essential References / Controlled Documents 6.2.1 Panasonic Operating Instruction Manual 6.2.2 Thermoluminescence Dosimetry Data Processing,. Interna-tional Science Associates.
7.O ATTACHMENTS 7.1 Figure 1, TLD Reader Calibration form 7.2 Figure 2, Program Modification Log I
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, : ,7 , ., V PDP-7 Figure 1 TLD READER CALIBRATION UD-806 TLD irradiation date/ time: /- Technician:
TLD delivered' dose (D) I m Dose:. mR High Dose: mR TLD reader serialf: Dose rate verified with:
Date/ time of cleaning ,
Panasonic Model.710A TLD reader : /
Sensitivity correction factor one hour after cleaning:
n n .,
. -I E4(1) E E4(i)
M Im Dose = i=1 -
M High Dose'= i=1 =
n n ,
PCCF = M Im Dose = FCCF = M High Dose ,
D Iow Dose D High Dose l PCCC = (current PCCC)/(PCCF) = (5A) FCCC = (current FCCC)/(FCCF) = _ (SB) i 1
Verifie'd lBl + S Im Dose = Verified lBl+SHighDose=
)
3 Battelle Test TLDs Category Deep lBl+S Shallow lBl + S I II i
VI VII Reviewed and accepted by: Date:
Rev. No. 3 Date 05/87 Page _ 13 of PDP-7 l _. __ _ _ _ _ _ _ _ _ _ - _ _ _ - s
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PDP-7 Figure 2 PROGRAM MODIFICATION II)G Program n ee: modification !
new program Requested by: Date:
Description of Mod or prog; ram requested:
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Lines nodified or inserted (use additional sheets if required):
List. data bases affected by this program:
y
- Listing of affected program seggent(s) attached l y
- Verification of software accuracy attached y
- Stored to master disk y s Stored to backup nunter disk y
- Stored to backup master tape Date completed: Initials:
Reviewer s sigrature:
Rev. No. 2 Date 05/87 Page 14 of PDP-7
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