ML19329A108
| ML19329A108 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/19/1976 |
| From: | Rosztoczy Z Office of Nuclear Reactor Regulation |
| To: | Baer R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912300128 | |
| Download: ML19329A108 (1) | |
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AB P.dg. File 3O~1 Robert Baer, Chief, Reactor Safety Branch, DOR I can not concur with the T-H writings on Oconee. We require a Tech.
Spec. limit on coolant flow.
See, for example, Pebble Springs or all standard plants. It is even more important to issue a Tech. Spec. on flow when a plant is taking credit for measured flow instead of design flow. Typically, the Tech. Spec. limit is 5% higher than _the flow used for safety evaluation. The 5% accounts for errors in the continuous monitoring device, drift and calibration errors. In addition to this 5%,
the applicant usually retains a 2 to 3% operating band. If the flow drops below the Tech. Spec. limit, power reduction is required. For details, see the Omaha or BG & E Tech. Spec.
The total 1% margin prop'o~sblon Oconee is o'aviously inadequate. There is no mention in the write-4 p of continuous monitoring and the uncer-tainties of continuous monitoring. Instead, reference is made to a three year-old measurement, that is not relevant to the new core. I am aware of the flux / flow trip; this trip, however, provides no help for occurrences when the primary protection is not the overpower trip.
There is no mention of how the uncertainties of the continuous flow
. measurement are accounted for in the setting of the flux / flow trip.
In light of the flow anomalies observed during the past few years, (BG & E, for example) I do not think we should let Oconee start up without a well-documented Tech. Spec. limit on coolant flow. The matter requires urgent attention.
Zoltan R. Rosztoczy, Chief Analysis Branch Division of Systems Safety y-cc:
D. Ross P. Norian R. Purple D. Eisenhut f.
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