ML20147G184
| ML20147G184 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 03/01/1988 |
| From: | Withers B WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | Martin R NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-88-001, IEB-88-1, WM-88-0047, WM-88-47, NUDOCS 8803080155 | |
| Download: ML20147G184 (4) | |
Text
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WW1.F CREEK NUCLEAR OPERATING CORPORATION Bart D. Withers gg, March 1, 1988 V'i 88-0047 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Vashington, D. C.
20555 Mr. R. D. Martin, Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011
Subject:
Dacket No. 50-482: Response to NRC Bulletin 88-01 Gentlemen:
The purpose of this letter is to transmit Wolf Creek Nuclear Operating Corporation's response to NRC Bulletin 88-01, "Defects in Vestinghouse Circuit Breakers", for Wolf Creek Generating Station, Unit No.
1.
This bulletin requested licensees using Vestinghouse series DS circuit breakers in Class 1E service to perform and document inspection of the welds on the pole shafts and inspection of the alignment in the breaker closing mechanism.
If you have any questions concerning this matter, please contact me or Mr.
O. L. Maynard of my staff.
Very truly yours, Bart D. Withers President and Chief Executive Officer BDW/11k Attachment oca B. L. Partlett (NRC), w/a P. W. O'Connor (NRC), 2 w/a 1
[j 8803080155 880301 PDR ADOCK 05000482
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P.O. Box dit / INrkngton, KS 66839 / Phone: (316) 364-8831 An EM opsclerWy Eryloyer M F HC. VET
STATE OP KANSAS
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Bart D. Withers, of lawful age, being first duly sworn upon oath says that he is President and Chief Executive Officer of Wolf Creek Nuolear Operating Corporations that he has read the foregoing document and knows the content thereof that he has executed that same for and on behalf -of said Corporation with full power and authority to do son and that the facts therein stated are true and correct to the best of his knowledge, information and belief.
By
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Bar't D. Withers President and Chief Executive Officer SUBSCRIBED and sworn to before me this
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day of h M, 1988.
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Attachment to VM 88-0047 Page 1 of 2 March 1,1988 RESPONSE TO NRC BULLETIN 88-01 I.-
Introduction NRC Bulletin No.
88-01, "Defects in Westinghouse Circuit Breakers",
was issued on February 5,
- 1988, to request addressees that use Vestinghouse series DS oircuit breakers in Class 1E service to perform and document inspection of the welds on the pole shafts and inspection of the alignment in the breaker closing mechanism.
Specifically, addressees using Vestinghouse DS-206, DSL-206, DS-416, DSL-416, and DS-420 circuit breakers in Class 1E applications, including reactor trip breakers- (RTB),
were requested to perform inspections in accordance with Vestinghouse Technical Bulletin NSID-TB-87-11, except for the following changes in the indicated sections:
6.0. Add the following
- However, inspection of the.3 main pole shaft welds for all RTBs (both main and bypass) should be completed within 30 days of receipt of this NRC bulletin.
6.1.1, 6.1.2, and 7.1 Add the following:
e) porosity - surface pin holes with oumulative diameters less than 1/16 inch in each inch of the weld.
6.2.4 Delete this section and the reference to it in Section 6.2 3 With regard to Section 6.2.4, any RTB with a pole shaft that does not meet the criteria of Section 6.1.2 should be deemed inoperable and should not be used in the operating or bypass breaker position in the reactor trip switchgear.
Such pole shaf ts should be removed from service and a replacement pole shaft installed in the brecker before returning it to service.
The replacement pole shaft should meet the l
oriteria in Section 6.1.1.
II.
Actions Taken At VCGS A review at Volf Creek Generating Station (VCGS) indicated that there are i
l five Westinghouse series DS oircuit breakers on site that would be or are being used in Class 1E applications. These breakers, all of which are model DS-416, include two reactor trip breakers, two bypass reactor trip breakers, and one spare in the warehouse.
I-
ffT
-e Attachment to WM 88-0047 Page 2 of 2 March 1, 1988~
Volf~ Creek Nuclear Operating Corporation (WCROC) was made aware of recommendations to inspect the DS series otrouit breakers by a Westinghouse letter dated September _11, 1987.
The info rmation in this letter was forwarded to the maintenance department and the inspections _were scheduled in conjunction with the second refueling outage preventative maintenance.
Subsequently, on December 1, 1987, Vestinghouse issued Technical Bulletin NSID-TB-87-11 which superseded the recommendations in the September letter.
During the inspection performed during the second refueling outage, it was discovered that some of welds were suspect and based on this information, a decision was made to replace the pole shafts on all five breakers.
WCNOC then procured 5 pole shaft assemblies from Westinghouse.
In the Certificate of Conformance supplied with the pole shaft assemblies, Westinghouse certified that the pole shafts meet or exceed the requirements of the short-term and long-term inspection procedures for the pole shaft welde_
as outlined in both the September letter and the Technical Bulletin.
The five
_ pole shafts were then replaced with the work being completed on December 12, 1987.
During the installation of the new pole shafts, the alignment of the breakers were checked using the procedure in the Westinghouse Technical Bulletin.
The results of th;s alignment check were satiefsotory with the requirements of the Westinghours Technical Bulletin being met for all five breakers.
L l'
On February 8,
- 1988, WCN00 received NRC Bulletin 88-01 which required
)
inspections for porosity in addition to the inspection criteria outlined in the Westinghouse Technical Bulletin.
To meet this requirement of the bulletin, an inspection of all the pole shaft welds was made on February 11,
All of the pole shaft welds met the acceptance criteria for porosity in NRC Bulletin 88-01.
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III. Conclusion There are five Westinghouse DS model circuit breakers used in Class 1E applications at WCGS.
All five breakers had their pole shafts replaced during the second refueling outage because of suspect welds. The short-term i
and long-te rm inspections performed by Westinghouse and WCPOC on the new pole shaf ts showed that they meet the criteria set forth in both the Westin6 ouse Technical Bulletin and NRC Bulletin 88-01.
Thecefore, no h
further action is required by VCN00 and this letter fulfills all of the reporting requirements of NRC Bulletin 88-01.
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