ML20205M127
| ML20205M127 | |
| Person / Time | |
|---|---|
| Issue date: | 04/11/1986 |
| From: | Zech G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Bronson B DRESSER INDUSTRIES, INC. |
| References | |
| REF-QA-99900054 NUDOCS 8604150092 | |
| Download: ML20205M127 (2) | |
Text
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April 11, 1986 Docket No. 999000054/85-01 Dresser Industries, Inc.
ATTN:
B. G. Bronson QA Manager Post Office Box 1430 Alexandria, Louisiana 71301 Gentlemen:
Thank you for your letter of February 10, 1986, in response to our letter dated January 17, 1986. As a result of our review, we find that additional information is needed.
Specifically, in regards to the Davis-Besse safety valve (serial number BM8633) that was returned to Dresser in 1981 and to the Diablo Canyon Units 1 and 2 safety valve (serial number BN1741) that was manufactured in 1971-1973, answers to the following questions would be appreciated:
Toledo Edison Company / Davis-Besse (safety valve serial number BM8635) 1.
When was this valve manufactured?
2.
What was the carbon and nickel content of the collar (CB-30)? What was the carbon content in the Type 304 stainless steel cotter pin analysis? What was the method of chemical analysis used to generate your alloy compositions?
3.
Where exactly were your hardness readings taken?
4.
Were the failed spindle threads flat, bright and shiny?
5.
What was the chemical analysis of the metal chips that were scattered on the top surface of the lower spring washer and the top surface of the cover plate?
6.
Were there any unique qualities about the spindle's post-failure microstructure?
7.
Did the cotter pin show any evidence of necking down?
Did the fracture surfaces show evidence of beach markings?
Pacific Gas & Electric Company /Diablo Canyon, Units 1 and 2 (serial number BN1741).
We agree with your conclusion that the evaluation of the Diablo Canyt,n safety valve failure was not completely stated and clear in regards to why "the 9
8604150092 860411 PDR GA999 ENVD 99900054
Dresser Industries, Inc. April 11, 1986
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failure is an isolated case." Your explanation is acceptable, however, the followirg questions remain concerning your evaluation.
1.
Was there a metallurgical failure analysis performed to determine the cause of the defective disc collar / spindle threads? If so, what were the results?
2.
What are the major changes that have occurred in Dresser's quality inspection program since 1973 to reasonably assure future nonrecur-rence of the subject problem?
3.
Which other nuclear power stations, excluding Davis-Besse, have safety valves of the same type and-design (as mentioned in your response paragraph 1.7)?
Nonconformance (85-01-07)
It is agreed that the four Section III rod ovens were calibrated according to schedule.
However, the nonconformance addressed a failure of Dresser's quality control to certify the calibration completed on June 6,1984 by either a stamp or a signature. As a result of a discussion with your Mr. Rod Thomas, we understand that the situation has been identified and corrected. No additional response is required.
Please provide the additional information within 25 days of the date of this letter. The response requested by this letter is not subject to the clearance procedures of the Office of Management and Budget as required by the Paperwork Reduction Act of 1980, PL 96-511.
Sincerely, ORIGINAL SIGNED BY:
GARY G. ZECt1 Gary G. Zech, Chief Vendor Program Branch Division of Quality Assurance, Vendor and Technical Training Center Programs Office of Inspection and Enforcement DIURIBUTION:
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