ML19224B140
| ML19224B140 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/19/1976 |
| From: | Metropolitan Edison Co |
| To: | Mullinix W NRC/IE |
| References | |
| 1607, TM-0076, TM-76, NUDOCS 7906140099 | |
| Download: ML19224B140 (6) | |
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TMI DOCUMENTS h~ O7
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DOCUMENT 140:
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0F DOCL'ENf PROVIDED BY COPY MADE ON METROPOLITAN EDISON COMPANY.
Wilda R. Mullinix, NRC I
7906140099 188 295 O
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MASTER COPY DO NOT REMOVE g;'"2
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01/19/76 THREE MILE ISLAND NUCLEAR STATION C0 0 ROLLED COP STATION HEALTH PHYSICS PROCEDURE 1607 AIR SAMPLING FOR RADIOACTIVE GAS Table of Effective Pages Pace Date Revision Pace Date R evision Pace Date Revision 1.0 01/19/76 2
26.0 51.0 2.0 02/06/75 1
27.0 52.0 3.0 02/06/75 1
28.0 53.0 4.0 02/06/75 1
29.0 54.0 5.0 02/06/75 1
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Cogniz; int Ohf t.4fead Cognizq'nt Oejt Head Unit 1 PORC Recommends Approval Unit PORC Recom ends Approval 0
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% Date Chairman of PORC ffy Chairman of PORC i
PORC comments of included PORC comments of included (date)
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Approval Date Appro M//>v D
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Quality Assurance Unit Superintendent m.ss.c t i.n e
i HPP.1607
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Revision 2 01/19/76 THREE MILE ISLAND NUCLEAR STATION STATION HEALTH PHYSICS PROCEDURES 1607 - Air Sampling for Radioactive Gas 1.0 PURPOSE The purpose of this procedure is to outline the steps to be taken for Air Sampling for Radioactive Gas.
2.0 DISCUSSION 2.1 Radioactive Gas Samples will be collected and analyzed for Beta and Gamma activities.
2.2 For the Beta, an A-100 Gas Chamber will be used.
2.3 For the Gamma, a 5 cc. glass vial, or a Marinelli Beaker with petcocks will be used.
3.0 REFERENCES
3.1 W. B. Johnson Catalog (Section-Lab. Equipment) 3.2 PCP 1958 3.3 HPP 1740 4.0 EQUIPMENT 4.1 Glass Sampling Flask (Marinelli Beaker) 4.2 A-100 Gas Chamber 4.3 Geli Detector / Multi-channel Analyzer System 4.4 GM Instrument 4.5 Pump or Hand Aspirator 4.6 Tygon Tubing 4.7 Aluminuia Flask (Marinelli Beaker) t 4.8 Scc. Glass Vial with Rubber Insert
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4.9 Syringe
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jgg 297 5.0 OPERATING INSTRUCTIONS 1.0 6
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HPP.1607 02/06/75
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Revision 1 5.1 Gamma Analysis of Radioactive Gas (Glass fiarinelli Beaker) 5.1.1 The Marinelli Beaker is filled with demineralized watcr so that all the air in the beaker has been displaced.
5.1.2 Connect the gas-inlet side of the Marinelli Beaker to the line or area from which the sample is to be taken.
5.1.3 Open the water-outlet petcock.
5.1.4 Open the gas-inlet petcock allowing the gas to be drawn in.
5.1.5 Close both petcocks when all the water has been removed.
5.1.6 The sample will then be taken to the lab and analyzed on the Multi-channel Analyzer /Geli Detector System as per P.C.P. 1958.
5.1.7 Forward completed date to Radiation Pretection Supervision for review and approval.
5.2 Gamma Analysis of Radioactive Gas (Aluminum Marinelli Beaker) 5.2.1 An Aluminum Marinelli Beaker will be connected in the line or in the area to be sampled.
5.2.2 Connect a pump to a stopcock of the Marinelli Beaker.
5.2.3 Start the pump and transfer at least three (3) times the 4
v.lume of the beaker (s2 X 10 cc.) through the Marinelli.
5.2.4 After making sure the petcock on either side of the Aluminum Marinelli Beaker is closed, remove the beaker and return it to the Count Room for analysis on the Multi-channel Analyzer /Geli Detector System as per P.C.P.
1958.
5.2.5 Forward completed data to Radiation Protection Supervision for review and approval.
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Revision 1 5.3 Gamma Analysis of Hiah Level Radioactive Gas (Scc Glass Vial) 5.3.1 When gamma analysis with a Marinelli Beaker yields a dead time of greater than 20% on the Geli Detector / Multi-channel System, a sample must be taken and counted using a 5cc. glass vial.
5.3.2 Using the 5cc. glass vial, take a syringe and place a slight vacuum on the glass vial.
(evacuate approximately 15 cc. of air from the vial).
5.3.3 Proceed to the sample point and using the syringe, take a 5 cc. sample and inject into the vial.
5.3.4 Take the sample to tha count room and analyze on the Geli Detector / Multi-chanrel System as per P.C.P.1958.
5.3.5 Forward completed c ata to Radiation Protection Supervision for review and approval.
5.4 Beta Analysis of Radioactive Gas 5.4.1 The A-100 Gas Chamber will be placed in the line or in the area to be sampled.
5.4.2 Either a pump or a hand aspirator will be used to transfer a 100 cc sample of gas to the chamber.
5.4.3 After making sure the petcock on either side of the A-100 is closed, remove and return to the Health Physics lab for analysi<.
5.4.4 Connect aa appropriate counting instrument to the A-100 chamber and count for 5 minutes.
I 5.4.5 The Activity will be determined using the following formula:
3-188 299 6
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HPP 3607 c
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Revision 1 CC/ Min.
= uCi/cc (Volume)(Etriciency)(2.22 x 10 )
6 CC/ Min. = corrected counts per minute.
Counts per minute minus background.
Efficiency:
efficiency for GM counter 2.22 x 106=
disintegrations per minute per microcurie.
5.4.6 If the corrected counts per minute is less than the minimum detectable count rate, the activity is reported as less than MDA.
NOTE:
The formula for MDCR is as follows:
BKG CPM MDCR = 3 Time BKG Count 5.4.7 Forward completed data to Radiation Protection Supervision for review and approval.
Examole for Beta Calculations:
A gas sample is counted for 5 minutes on the GM counter.
The total cour ts are 225, the efficiency for the GM is 20% and the background 12.5 cpm.
Determine the activity.
Volume of sample = 100 cc.
225 counts = 45 cpm 5 minutes 45 cpm minus 12.5 cpm bkg 32.5 cc/ min 32.5
. = 7.32 x 10-7 pCi/cc (100)(.20)(2.22 x loo)
Examole of the use of MDCR A gas sample is counted for 5 minutes on the GM Counter.
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The total counts are 85; efficiency for the GM is 20% and the background is 12.5 cpm with a background counting time of 4 minutes.
Determine the activity.
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HPP ]607 02/06/75 Revision 1 pj[ - 12.5 = 4.5 cc/ min 5
MDCR 3 12.5 cpm = 5.3 cpm 4 min.
The corrected counts per minute, 4.5 cpm, of the sample is less than the minimum detectable count rate, 5.3 cpm; therefore the MDCR is used in the formula to determine pCi/cc (MDA):
MDA =
5.3
= <l.2 x 10-7 pCi/cc (100)(.20)(2.22 x 10")
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