ML19329A396
| ML19329A396 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/27/1977 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19329A395 | List: |
| References | |
| PROC-770527, NUDOCS 8001030967 | |
| Download: ML19329A396 (1) | |
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ATTACHMENT A PROCEDURE FOR TESTING' SCINTILLATION COUNTER CRYSTALS TO DETERMINE CRYSTAL FD.ACTURE OR DEGRADATION Materials needed:
Snali check source consisting of gamma ;mitter such as ts-137.
Source should be small in physical size, i.e.,
about 0.25" x 0.25".
Procedure 1.
Remove detector assembly from monitor wel1. Detector cable assembly should remain connected to monitor.
2.
Place source in first position as in diaarams, below:
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[1 4
5 3
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CRYSTAL END OF DETECTOR 1
5 3
ASSEMBLY 2
3.
Make count determination, i.e., count rate, for position #1.
Record count rate.
4.
Reoeat step 3 for positions 2, 3, 4, and 5.
Interpretation Count rates at positions 1, 2, 3, and 4 should be approximately eaual.
Count rate at position 5 should be somewhat hiaber.
If count rate at any point varies substantially, this is indicative of either crystal internal fracture or separation of crystal fron class face pl ate. To verify, disconnect detector assembly from monitor cable and dis-assemble components.
Inspect crystal visually for defects. Any visible crack in the crystal, any.secaration of crystal from class face plate as evidenced by bubbles under class, or aonarent discoloration (yellowina of crystal) indicates a defective crystal and that crystal should be replaced.
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