ML20134F485
| ML20134F485 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/25/1996 |
| From: | Donnelly P CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9611050345 | |
| Download: ML20134F485 (2) | |
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C0flSumers Power Patrick M Donnetty g
Plant Afanum AIKN0GAW5 PROGRE55 8eg Rock Point Nuclear Plant,10269 US 31 North, Charlevois. MI 49720 i
October 25, 1996 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - SCRAM TIME TESTING; TERMINATION OF COMMITMENT MADE IN LETTER FORWARDED MARCH 11, 1996.
I Consumers Power Company Letter forwarded March 11, 1996, in response to
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recommendations made by the Boiling Water Reactor Owners Group Regulatory Response Group (BWROGRRG), stated that Big Rock Point would perform scram time testing on a reference nurloer Of Control Rod Drives (CRDs) during the next plant shutdown following 90 days of operation. The letter stated that Big Rock Point would continue to monitor General Electric's evaluation of the problem and may revise its commitment based on the results of the investigation.
In late August of 1996, General Electric issued their evaluation report (NEDC-32646P). The report concluded that the delayed scram times were caused by the adhesion effect of the Viton A exhaust port diaphragm. The results of the report, along with other committee activities involved with replacement elastomers, were discussed with the Nuclear Regulatory Commission during a conference call conducted August 27, 1996.
As described in Consumers Power Company's previous submittal, Big Rock Point elected to replace Viton A scram solenoid pilot valve (SSPV) exhaust port diaphragms with BUNA-N prior to start-up from the first quarter 1996 refueling outage. Therefore, the adhesion problem should not be applicable to Big Rock Point because of the difference in materials employed.
On September 10, 1996, the plant was removed from service after 156 days of operation to repair a packing leak on a Reactor Depressurization System l
Isolation valve. CRD performance testing was conducted on five CRDs. All five drives met the Technical Specification timing requirements of less than or equal to 0.600 seconds for 10% insertion; and less than or equal to 2.50 seconds for 90% insertion. From this experience and General Electric testing, BUNA-N appears to be free of the adhesion effects demonstrated by Viton A testing.
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9611050345 961025 PDR ADOCK 05000155 L
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NdCLEARREGULATORYCONMISSION 2
BIG ROCK POINT PLANT SCRAM, TIME TESTING
,, October 25, 1996 Since Big Rock Point decided to replace the Viton A (SSPV) exhaust port diaphragms with BUNA-N, and that the change in scram times are caused by the adhesion effect of Viton A, Consumers Power has concluded that additional scram time testing provides no continued benefit in resolving the industry issue of degrading scram times. Therefore, the commitment to perform scram time testing on a reference number of CRDs during the next plant shutdown followi 90 days of eration h been satisfied.
1 Patrick M Donnelly Plant Manager CC: Administrator, Region III, USNRC NRC Resident Inspector - Big Rock Point