ML20212H110
| ML20212H110 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 01/15/1987 |
| From: | Musolf D NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| GL-83-28, NUDOCS 8701210282 | |
| Download: ML20212H110 (2) | |
Text
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Northem States Power Company 414 Nicollet Mall Minneapohs. Minnesota 55401 Telephone (612) 330-5500 January 15, 1987 Generic Letter 83-28 Items 4.2.3 and 4.2.4 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Response to Generic Letter 83-28. Items 4.2.3 and 4.2.4 This letter is provided in response to Items 4.2.3 and 4.2.4 of Generic Letter 83-28, " Required Actions Based on Generic Implicat. ions of Salen ATWS Events".
Items 4.2.3 and 4.2.4 of Generic Letter 83-28 specify that the reactor trip breaker preventative maintenance and surveillance program should include life testing of the reactor trip breakers and periodic replacement of breakers or components consistent with the demonstrated life cycles.
In response to Item 4.2.3, NSP supported the Westinghouse Owner's Group (WOG) reactor trip breaker Life Cycle Testing Program.
The results of that program have in turn been utilized in the development of our response to Item 4.2.4 discussed below.
The WOG Life Cycle Testing Program cycled reactor trip breaker shunt trip attachments (STA) and undervoltage trip attachments (UVTA) through 2500 trip operations with no failures to trip or significant performance degradation.
Based on this testing, the recently revised Westinghouse DB-50 Reactor Trip Breaker maintenance manual recommends a replacement interval of 2500 cycles of operation for the STA and the UVTA.
Using this recommended replacement interval and a conservative estimate for the number of cycles per year for the trip attachments, the following UVTA and STA replacement intervals are being implemented at Prairie Island:
Component Replacement Interval Main Reactor Trip Breaker UVTA 30 years Main Reactor Trip Breaker STA 43 years Bypass Breaker UVTA 50 years Bypass Breaker STA
>100 years A 0' f' 8701210282 870115 ff0 PDR ADOCK 05000282 P
U S NRC January 15, 1987 Northem States Power Company Page 2 These replacement intervals will be based on an inservice date for the components of one year prior to initial unit operation. Methodology will be developed to ensure that the UVTA's and STA's are replaced at the specified intervals.
The remaining reactor trip breaker components, not specifically addressed by the WOG Life Cycle Testing Program, will be replaced as periodic preventative maintenance, inspection and surveillance testing dictate.
A discussion of the periodic replacement of reactor trip breaker components will be included in the next revision to the Prairie Island Updated Safety Analysis Report.
Please contact us if you have any questions concerning this response.
M Ms David Musolf Manager - Nuclear Support Services DHM/EFE/efe c: Regional Administrator-III, NRC NRR Project Manager, NRC Resident Inspector, NRC G Charnoff
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