ML20197F553
| ML20197F553 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay, 05000000 |
| Issue date: | 11/26/1973 |
| From: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Searls F PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8104300158 | |
| Download: ML20197F553 (6) | |
Text
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l NOV 2 61973 Docket No. 50-133 Facific Cas and Electric Company r
ATIN:
Mr. Frederick T. Searls Vice President and Cenatal i
Counsel 77 Beale Street San Francisco, California 94106 Gentlemen:
We have been reviewing the information you submitted concerning the i
reactor protection systems for the Humboldt Bay Power Plant Unit No. 3, Facility License No. DPR-7. The matter has been discussed on several g
occasions with representatives of FG&E.
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Eased upon our review of your report, "Facific Ces and Electric Company, Eumboldt Bay Power Plant Unit No. 3. Failure Mode Analysis of Beactor c
- _r Protection Systems", dated January 1970 and subsequent discussions,
_ R we agree that the modifications to the protective system described in l
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the subject report will improve overall system reliability. We have j
5 reviewed your latter dated April 6,1972, and concluded that all j
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essential safety related electrical equipment is capable of surviving l
3 potentially hostile environmental conditions resulting from a lose-1 g
of-coolant accidtsat until after its safety function has been performed.
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Bowever, we consider it important to safety that the scram system j
h and automatic enginc.ered safety features of a power reactor satisfy j
l-the single failura c.riterion as defined in Section 4.2 of IEEE Standard
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279-1963, " Criteria for Nuclear Power Plant Protection Systems", and i
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the General Desig% Criteria of Appendix A to 10 CFR Part 50. Therefore, j
the scram system lpgic circuits and the automatic engineered safety feature initiating
- circuits in the Humboldt Bay Unit No. 3 should L5,
be replaced or mod}fied to satisfy Section 4.2 of IEEE Standard 279-1968.
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Following these modifications, you should provide assursace that a single failure in c)e de system could not fail any set of redundant safety features.
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Pacific Cao and Electric Company -
NOV 2 61973 We find that these improvements in the plant protection system will provide substantial, additional protection for the health and safety of the public and that auch improvements are required for the health and safety of the public. Therefore, pursuant to section 30.109, "Backfitting", of 10 CFR Part 50, you are hereby directed to submit, within 90 days from the date of this letter, your plans for imple-meeting the above modifiestions. Further, you are hereby directed to aceplete within see and one-half years from the date of thia letter, all such modifientions and tests asseseary to conform to
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the requirements of the single failure eriterion.
Simeerely.
Drfgnal S!gned By h_%usw A. Giamb iso, Deputy Director for Raaetor Projects i
Directorate of Licensing
Enclosure:
Safety Evaluation se: Philip A. Crane, Jr.
Pacific Gas and Electric Company 77 Beale street j
san Franaiano, California 94106 n u ;. <
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