ML20050J337
| ML20050J337 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 04/09/1982 |
| From: | Schroeder C COMMONWEALTH EDISON CO. |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| 3855N, NUDOCS 8204140179 | |
| Download: ML20050J337 (3) | |
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i Commonwzith Edison One First National Plaza, Chicago, Illinois
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'g/ Address R: ply to: Post Office Box 767 Chicago. Illinois 60690 April 9, 1982 t
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Mr. A. Schwencer, Chief Licensing Branch #2 rg
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Division o f Licensing U. S. Nuclear Regulatory Commission g
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Washington, DC 20555 N
Subject:
LaSalle County Station Units 1 and 2 Diesel Generator NRC Docket Nos. 50-373 and 50-374 References (a):
C.
Schroeoer letter to A. Schwencer dated March 25, 1982, " Diesel Generator Starts" (b):
C.
Schroeder letter to A. Schwencer dated March 25, 1982, "ESF Divisions 1 and 2 Diesel Generators Voltage and Frequency Requirements during the ECCS Loading Sequence"
Dear Mr. Schwencer:
The purpose of this letter is to provide you with additional information on diesel generator issues which were discussed with Dr. Bournia, et al, o f your staf f on April 8, 1982.
During the last several years, the NRR staf f and manage-ment have indicated on numerous occassions that the requirement for counting diesel generator starts would be in accordance with the t
requirements of Technical Specification Table 4.8.1.1.2-1, Diesel Generator Test Schedule.
This table requires that "For the purpose of this test schedule, only valid tests conducted a f ter the OL issuance date shall be included in the computation of the last 100 valid tests.
Entry into this test schedule shall be made at the 31
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i day test frequency."
Commonwealth Edison Company has believed that i
the position indicated in discussions with the staf f and documented in Technical Specification Table 4. 8.1.1. 2 -1 clearly represented the requirement to be imposed in this matter.
On March 18, 1982, in a telecon with Dr. Bournia, et al, additional information was requested regarding the history of diesel generator starts and failures since their respective 23 start tests.
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This information was provided in Reference (a).
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PDR ADOCK 05000373 A
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A. Schwencer April 9, 1982 The 388 valid starts documented in Reference (a) plus the 92 (4 x 23) valid starts in the four 23 start tests give a history of approximately 480 valid starts with only six documented failures.
These failures were described in Reference (a).
This represents an overall f ailure to start rate o f approximately one out o f 80.
i In addition, as explained in our telecon on April 8,
- 1982, there have been 134 valid starts in 134 diesel generator start attempts since December 26, 1981.
In these 134 starts, there were interspersed 25 full valid tests as defined in Regulatory Guide 1.108.
All o f these 134 valid starts could have been continued to l
full vallo tests in accordance with Regulatory Guide 1.108.
As was explained in Reference (a), diesel generator starts have been done for a variety of reasons, including for preoperational tests, main-tenance, operator training, and machinery exercise.
Therefore, not all diesel starts have been continued to full valid tests.
BASED ON THE THEN PUBLISHED NRC POSITION IN TECHNICAL SPECIFICATION T ABLE 4.8. I. l.2-1 AND CONTINUED CONF IRMA T ION FROM NRR STAFF AND MANAGEMENT THAT THE TECHNCI AL $PECIFICATION REPRESENTED THE NRC POSIT ION, COMMONWEALTH EDISON IN GOOD FAITH BELIEVED THAT IT WAS NOT NECESSARY TO CONTINUE ALL STARTS TO VALID TESTS.
It is also noted that of the six failures that were documented in Reference (a), none of the f ailures a ffected the loading o f the diesels.
The point of failure was in the starting of the diesel / generator in the test.
The 134 valid starts thus indicate that the previous causes of failure have been adequately i
addressed.
Based on the approximate overall f ailure to start rate o f l
only one in eighty, and the fact that out of the last 134 start attempts, there have been 134 valid starts, Commonwealth Edison Company concludes that we have continued to demonstrate the high reliability of our diesel generators.
We expect the NRC staff and l
management to continue their historical documented position that, for the purposes of Technical Specification Table 4.8.1.1.2-1, only i
valid tests conducted af ter the OL issuance date shall be included in the computation o f the last 100 valid tests and that entry into the test schedule shall be made at the 31 day test frequency.
In Reference (b), Commonwealth Edison provided you with information requested during a telecon with Dr. Bournia, et al, on diesel generator voltage and frequency requirements during the ECCS l
loading sequence.
During our telecon on April 8, 1982, the following Technical Specification change was agreed to:
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A. Schwencer April 9, 1982 TABLE 3.3.3-2, Page 3/4 3-30 Add:
Trip Allowable Setpoint Value D.l.C.
For Divisions 1 & 2 with a sustained voltage o f 60% (2496V), the undervoltage time delay shall be
)P 4 seconds
>3 seconds It is our understanding that this Technical Specification change fully resolves that issue.
If there are any further questions in this matter, please contact this of fice.
Very truly yours, W W whles-C.
W. Schroeder Nuclear Licensing Administrator 1m cc:
NRC Resident Inspector - LSCS t
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