ML19331D029
| ML19331D029 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 08/15/1980 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| TAC-42933, NUDOCS 8008270139 | |
| Download: ML19331D029 (3) | |
Text
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'o, UNITED STATES Q
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August 15, 1980 Docket No. 50-312 Mr. J. J. Mattimoe Assistant General Manager and Chief Engineer Sacramento Municipal Utility District 6201 S Street P. O. Box 15830 Sacramento, California 95813
Dear Mr. Mattimoe:
In our review of the Crystal River Unit No. 3 (CR-3) event of February 26, 1980, the staff identified a situation in which the failure of the non-nuclear instrumentation (NNI) or the integrated control system (ICS) power supply can result in the automatic opening of the atmospheric dump valves (ADV) to the fifty percent open position with a lack of valve position indication.
Such an anomaly could significantly aggravate an overcooling transient.
The Florida Power Corporation has acknowledged this problem and has conmitted to provide, prior to restart of CR-3, a manual override closure capability of the ADV.
We have investigated the use of the ADV at other operating B&W plants and found that Rancho Seco and Three Mile Island, Unit No. I have a situation similar to CR-3.
Our investigation of these two plants indicates that upon loss of ICS power supply the ADVs automatically opens to a fifty per-cent position. On loss of NNI power the failure mode of the valve depends on the specific node of power failure.
Based on the above, we conclude that this condition is a design deficiency for both TMI-1 and Rancho Seco and request that corrections t,e made in a timely manner, including providing a reliable position indication.
Specifically, you are requested to conmit to modify your design (or provide acceptable justification), a description (including the appropriate elec-trical schematic diagrams of the proposed modifications) and an implementation l
schedule.
We request that you submit your response on this matter within 45 days fol-lowing receipt of this letter.
Sincerely, N
Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing cc: See next page
[ 8 0 08 :37 0 l%
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SacraEnts Municipal Utility District cc w/ enclosure (s):
.l, Christopher Ellison, Esq.
't David S. Kaplan, Secretary and Dian Grueuich, Esqdommission General Counsel California Energy 1111 Howe Avenue 6201 S Street j
Sacramento, California 95825 P. O. Box 15830 Sacramento, C'lifornia 95813 a
Ms. Eleanor Schwartz
. I' California State Office Sacramento County 600 Pennsylvania Avenue, S.E., Rm. 201 i
Board of Supervisors 827 7th Street, Room 424 Washington, D.C.
20003
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Sacramento, California 95814 I
Docketing and Service Section Office of the' Secretary Business and Municipal Department U. S. Nuclear Regulatory Commission Sacramento City-County Library Washington, D.C.
20555 828 I Street Sacramento, California 95814 REsidentInspector Of
, Technical Assessment hg.
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alifornia 95628 Office of Radiation Programs Dr. Richard F. Cole U. S nv rennental Protection Agency 1
Crystal llall #2 U. S. Nuclear Regulatory Commission Arlington, Virginia 20460 Washington, D.C.
20555 U. S. Environmental Protection Agency Mr. Frederick J. Shon Region IX Office Atomic Safety and Licensing Board ATTN:
EIS COORDINATOR Panel 215 Fremont Street U. S. Nuclear Regulatory Commission San Francisco, California 94111 Washington, D.C.
20555 Mr. Robert B. Borsum Elizabeth S. Bowers, Esq.
Babcock f. '.lilcox Chairman, Atomic Safety and "edear Power Generation Division Licensing Board Panel
'uite 420, 7735 Old Georgetown Road U. S. Nuclear Regulatory Commission
!at!esda, Maryland 20014 Washington, DC 20555 Thomas Caxter, Esq.
Shaw, Pittman, Potts & Trowbridge 1800 M Street,'l!N
- !ashington, D. C. -2003G Herbert H. Brown, Esq.
Mr. Michael R. Eaton Lawrence Coe Lanpher, Esq.
Energy Issues Coordinator riill, Christopher and Phillips, P. C.
Sierra Club Legislative Office 1900 M St., NW 1107 9th St., Room 1020 Washington, D. C.
20036 Sacramento, CA 95814 i
Halen Hubbard P. O. Box 63 Sunol, California 94586
i Sacramento Municipal Utility District cc w/ enclosure (s):
Atomic Safety and Licensing Board Panel U. S. Nuclear Regulatory Commission L'ashington, D.C.
20555
' L Atonic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission L'ashington, D.C.
20555 California Department of Healtn ATT1: Chief. Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California l
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