ML19351A451
| ML19351A451 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/12/1989 |
| From: | Barr K, Harmon P Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| PNO-ADSP-89-008, PNO-ADSP-89-8, NUDOCS 8912140237 | |
| Download: ML19351A451 (2) | |
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December 12, 1989 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-ADSP-89-08 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the ADSP staff on this date.
FACILITY: Tennessee Valley Authority Licensee Emergency Classification:
Sequoyah Unit 1 Notification of Unusual Event Docket No. 50-327 Alert Soddy Daisy, Tennessee Site Area Emergency General Emergency X
Not Applicable
SUBJECT:
SEQUOYAH UNIT 1 RHR PUMP OPERABILITY On November 29, 1989, TVA determined during ASME Section XI pump testing, that the Residual Heat Removal (RHR) pumps for Unit 2 did not meet acceptance criteria for individual pump differential pressure.
Specifically, the 2B RHR pump differential pressure was in excess of 200 pounds per square inch-differential (psid), and the acceptable range was between 165 and 184 psid. The licensee dispositioned the problem through an engineering evaluation which concluded eat the stronger pump was not preventing flow in the weaker pump (deadheading).
After reviewing the test data and the disposition of the deficiency, the NRC resident staff requested the licensee to ensure that the Unit 1 RHR pumps could also meet minimum flow requirements when both pumps were running. On 12/05/89, the licensee performed a test run with both pumps on line. This test determined that the 1A pump was not developing flow, and was being deadheaded by the stronger 1B pump. Since both pumps are started and discharge to a common line when initiated by a Safety Injection ($1) signal, a possibility existed that the 1A pump could be deadheaded during an 51 initiation. TVA's initial disposition of this problem was to place the IB pump in the Pull-to-Lock position to prevent its starting under SI conditions.
Previous evaluations had determined that the RHR pumps could be run without flow (deadheaded) for as long as 10 minutes without sustaining damage.
As a result of additional discussion with NRC staff. TVA has performed a safety l
evaluation, in accordance with 10 CFR 50.59, and has determined that it is acceptable to make procedural changes to put one RHR pump in the Pull-to-Lock position af ter receipt of an SI signal and after operator assessment of the plant conditions.
l l
NRC staff continues to review the actions of TVA on this issue.
l Media attention has occurred.
The State of Tenr.cessee has been informed.
CONTACT:
P. Harmon K. Barr (615)842-8001 FTS: 841-0342
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/3t 8912140237 891212 l
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89-008 PDC
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