ML19224B198
| ML19224B198 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/25/1977 |
| From: | Metropolitan Edison Co |
| To: | Mullinix W NRC/IE |
| References | |
| 1711, TM-0118, TM-118, NUDOCS 7906140203 | |
| Download: ML19224B198 (5) | |
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i TMI DOCUMENTS DOCUMENT NO:._
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METROPOLITAN EDISON COMPAIN.
Wilda R. Mullinix, NRC 79061402O3 192 154
Revision 3
1711 02/25/77 THREE MILE ISLAND NUCLEAR STATION 5
STATION HEALTH PHYSICS PROCEDURE 1711 EFFICIEriuY DETERMINATI0ft FOR PACKARD TRI-CARD Table of Effective Pages Page Date Revision Pace Date Revision Pace Date Revision 1.0 02/25/77 3
26.0 51.0 2.0 09/17/75 2
27.0 52.0 3.0 09/17/70 2
28.0 53.0 4.0 09/17/75 2
29.0 54.0 5.0 30.0 55.0 6.0 31.0 56.0 7.0 32.0 57.0 8.0 33:0 '7mm Ci' LV
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58.0 9.0 3h0h ' I a.U LLLU, 59.0 10.0 35 0 60.0 36)bl AS i t.R COPSf 11.0 6i.0 12.0 37.0 62.0
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.M Date 2// 9 /77 Approval s2 n
Cognizar.t Cept. Head Cognizant Dept. Head Unit 1 PORC comm nds TApproval Unit 2 PORC Secommerds Approval f
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1711 Revision 3 THREE MILE ISLAtiD fiUCLEAR STATION STATI0tl HEALTH PHYSICS PROCEDURE 1711 - Ef ficiency Determination Packard Tri-Carb 1.0 PURPOSE The purpose of this procedure is to outline the method used to determine the counting efficiency of the Packard Tri-Carb.
2.0 DISCUSSION 2.1 It is important with radiation counters to know the efficiency with which it detects (counts) the radioactive material.
Counting efficiency may be affected by disintegration energy, geometry, quenching, etc.
2.2 TMI aqueous sar.ples will be radioassayed for tritium content.
Uniformity of samples (counting, preparation of samples, impurities in samples, etc.) removes the requirement of goemetry and quenching in the efficiency determination.
2.3 Efficiency determinations should be performed with each sample set being counted.
2.4 Efficiency standard samples are normally prepared on a minimum of a monthly frequency or at the initiation of use of a new allotment of scintillation liquid.
2.5 Tritium standards for efficiency determination should be in the activity range of 100,000 dpm.
3.0 REFERENCES
3.1 Packard Model 3320 Liquid Scintillation Spectrometer 3.2 Instruction Manual j
3.3 H.P.P.1741 - Operation of Packard Tri-Carb.
92 156 1.0
09/17/75 1711 Revision 2 4.0 ECUIPMENT 4.1 Packard Model 3320 Liquid Scintillation Spectrometer 4.2 Scintillation counting vials (low K) 4.3 Scintillation counting solution (Instagel or equivalent) 4.4 Tritium Standard Solution 4.5 Pipettes 4.6 Graph paper 5.0 OPERATING INSTRUCTIONS CAUTION:
DO NOT switch sample changer to STOP unless a sample is counting.
Insure that no labels are placed on the sides of the counting vials.
5.1 Insure instrument controls are set as follows:
CONTROL POSITION Mode Selector Preset Auto Preset Time 10 (or as desired)
Minutes - Seconds Minutes Preset Count 900,000 Display Channel # 1 Window A-B
- Lower Discrim 50 Units X Upper Discrim As described in 5.5.2 of HPP 1741 Sample Charger Stop Gain See HPP 1741 5.2 Prepare standard counting samples of known dis / min activity using
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suggested guidelines of Section 6.
2.0 192 157 e
09/17/75 1711 Revision 2 5.3 Place the standard samples in the changer. Wipe the outside of the vial to remove fingerprints, etc., and insert in the counting instrument.
Place a " start" tower (green) in front of the sample (s) and a step tower (red) behind.
5.4 Allow 30 minutes elapsed time with the cover closed; then turn the SAMPLE CHANGES switch to OPERATE.
5.5 When a counting cycle is completed, switch the SAMPLE CHANGER to STOP durina a subseouent count.
5.6 Record counting data on Fom 1701-1.
5.7 Calculate the efficiency for each standard type using the method of Section 6.
5.8 Record and plot the efficiency determined on the efficiency curve, located in the background and efficiency log book.
5.9 Insure that the current efficiency is within the + Z. Sigma ~ perating range.
o If not, contact the Radiation Protection Foreman.
6.0 STANDARD PREPARATION, CALCULATIONS AND EXAMPLE 6.1 Environmental and other low level samples.
6.1.1 Into a clean counting vial pipette:
15.0 mis Instagel solution 5.0 mis Known Standard solution (See 6.3.1) 6.1.2 Cap tightly, shake vigorously, and label with date (on the cap only),
and activity in dis,
mln 6.2 Primary coolant and other high level samples
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3 6.2.1 Into a clean counting vial pipette:
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10.0 mis Instagel Solution 1.0 ml Known Standard solution (See 6.3.2) 6.2.2 Cap tightly, shake vigorously, and label on the cap only.
192 158 3.0
09/17/75 1711 Revision 2 6.2.3 Wipe outside of vial to remove fingerprints etc., and insert in counting instrument.
6.3 Aqueous Standard Solution 6.3.1 Use an aqueous solution of a known standard with a specific activity of approximately 500 dis / min /ml.
6.3.2 Use an aqueous solution of a known standard with a specific activity of approximately 200,000 dis / min /ml.
6.4 Calculations
dis dis / min x mls
=
min mi counts efficiency % = min X 100 d1s min (Standard)
M 4.0 k) 3l
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