ML19317F782
| ML19317F782 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/18/1975 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19317F780 | List: |
| References | |
| NUDOCS 8002210548 | |
| Download: ML19317F782 (2) | |
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SACRAMENTO MUNICIPAL UTILITY DISTRICT C ' 1708 59th Street. Box 15830, Sacramento, California 95813:(916) 452 3211
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February 18, 1975
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Directorate of I..ensing
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'd Docket 3o.30-312 Abnormal Occurrence A0-50-312-75-2
Dear Sir:
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9'i As defined by Proposed Amendment No. 30 to Technical Specifications -
for the Rancho Seco Nuclear Power Station, Section 6.9.1, and Regulatory Guide 1.16, Rev. 3, Section 2.b(1), we are reporting the following Abnormal
_0ccurrence as A0-75-2.
J On January 22, 1975 borated water was being recirculated to the Borated Water Storage Tank for mixing after adding makeup. The recircu-lation path was from the storage tank to the "A" Decay Heat Pump and Cooler through the system cross-tie line and flow meter and back to the storage rank via the recirculation line. The operator noticed that the flow instrumentation (FE-26048) was not operating and reported the problem..
The flow instrumentation and two motor operated valves were back-fitted to the cross-tie line to resolve a problem encountered during the licensing process. The hypothesized accident involved a break in one of the core flood tank lines and a failure of a decay heat pump in the opposite line.
In this case the system would noc have the capacity of low pressure injection and long term recirculation for core cooling.
The problem was reselved"by adding the cross-tie line with the two motor operated' valves and a flow meter capable of measuring flow in either direction. 'This will permit low pressure injection using the operable decay. heat pump and the nonfailed-core flood tank line to the reactor vessel. This' modification was approved and installed just prior to
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initial reactor startup.
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- Director Directorate of: Licensing February 18, 1975 4
-A check of the flow meter revealed that the flow transmitter was not e
valved in af ter installation and a.n. operator valve position list had it y
"noted" as out of service on November 7 -1974.
To prevent a reoccurrence F- > >
two actions are being taken:
1).
The importance of the valve lineups and abnormal conditions will be re-emphasized with the Shift Supervisors.
2)
A test of the cross-tie line to measure flow will be'added to the quarterly decay heat pump' surveillance test.
Both flow transmitters wece calibrated, put into service and tested on.
January 23, 1975.
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The reactor was at steady state 75% power and the loss of the flow ~
transmitter'did not cause any transient.
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Respectfully, O.[. Jubd
'. J. Mattimoe 4
Assistant General Manager
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and Chief Engineer e>
Enclosure cc:
R.~H.LEngelken, Region V e
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