ML20090H564
| ML20090H564 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Susquehanna |
| Issue date: | 02/03/1984 |
| From: | Rubenstein L Office of Nuclear Reactor Regulation |
| To: | Mattson R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17139C189 | List:
|
| References | |
| FOIA-84-105 NUDOCS 8402140590 | |
| Download: ML20090H564 (1) | |
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.g NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
% g t< /, p FB 3 1984 NOTE FOR: Roger J..Mattson, Director, DSI FROM:
L. S. Rubenstein, AD for Core & Plant Systems, DSI
SUBJECT:
NEED FOR REVISION OF TECHNICAL SPECIFICATION 3.4.1.1 FOR SUSQUEHANNA UNIT 2 We feel that this Technical Specification, which provides limiting conditions (hours) for operation in natural circulation and with only one recirculation loop, is not sufficiently prescriptive to protect again:;t the potential for thermal hydraulic instability. As you may be aware, GE recently presen~ted the staff with stability test data which demonstrated the occurrence of limit cycle neutron flux oscillations at natural circulation and several percent above the rated rod line.
The oscillations were observable on the APRM's and were suppressed with control rod insertion.
It was predicted that limit cycle oscillations sould occur at the operating condition tested, however; the charac-teristics of the observed ost!11ati';ns were different than those pre-viously observed at other stability tests.
Namely, the test data showed that some LPRMs oscillated out of phase with the APRM signal and at an amplitude as great as six times the core average.
General Electric is preparing a SIL for release in about two weeks to alert their plant's of this new data and to recommend actions to avoid and control abnormal neutron flux oscillations.
The staff has reviewed the GE SIL and feels that the actions proposed are good and prudent.
The CPS staff has contacted the Susquehanna project manager and will be
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working with the applicant to see that the final Susquehanna Technical Specification 3.4.1.1 is amended to properly protect against the po-tential for thermal hydraulic instability.
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L. S. Rubenstein, AD for Core & Plant Systems, DSI
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