ML20199J408
| ML20199J408 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 06/10/1986 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-86, REF-PT21-86-247-000 ANPP-36834-EEVB, DER-86-17, PT21-86-247, PT21-86-247-000, NUDOCS 8607080336 | |
| Download: ML20199J408 (4) | |
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A Arizona Nuclear Power Project P.O. BOX 52034 e PHOENIX, ARIZONA 85072-2034 June 10, 1986 ANPP-36834-EEVB/LAS/DRL-92.11 U. S. Nuclear Regulatory Commission
.s Region V 4..
1450 Maria Lane - Suite 210 F
m Walnut Creek, California 94596-5368 i'-
Attention:
Mr. D. F. Kirsch, Acting Director g
g Division of Reactor Safety and Projects
-: A Palo Verde Nuclear Generating Station (PVNGS) g Units 1, 2, 3 r'
Docket Nos. 50-528, 529, 530
Subject:
Final Report - DER 86-17 A 50.55(e) and 10CFR21 Reportable Condition Relating to Carbon Steel Guides in Stainless Steel Gate Valves File: 86-006-216; D.4.33.2
Reference:
(A) Telephone Conversation between R. C. Sorenson and D. R. Iarkin on April 29, 1986.
(Initial Reportability - DER 86-17)
(B) ANPP-36697, dated May 29, 1986.
(Interim Report - DER 86-17)
Dear Sir:
Attached, is our final written report of the Reportable deficiency under 10CFR50.55(e) referenced above. The 10CFR21 evaluation is also included.
Very truly yours, EEk bu E.jg E. E. Van Brunt, Jr.
Executive Vice President j
Project Director EEVBJr/DRL:kp Attachments
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8607080336 860610 DR ADOCK 05000528 PDR
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y ANPP-36834-EEVB/LAS/DRL-92.11 June 10, 1986 DER 86 Final Report Mr. D. F. Kirsch Acting Director Page Two ec: Mr. J. M. Taylor, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555 A. C. Gehr (4141)
R. P. Zimmerman (6295)
Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway - Suite 1500 Atlanta, Georgia 30339 i
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FINAL REPORT - DER 86-17 DEFICIENCY EVALUATION 50.55(e)
ARIZONA NUCLEAR POWER PROJECT (ANPP)
PVNGS UNITS 1, 2, 3 I.
Description of Deficiency During the Unit 3 91FL-3SIO2 flushing operation, bright metallic particles were detected in the flush strainers.
Following disassembly and inspection of twenty (20) Unit 3 valves and chemical analysis of guide rail samples, it was determined that four (4) Unit 3 Safety Injection valves had low alloy steel (AISI 4140 or 4150) guides instead of the required 316 stainless steel.
These four valves were Combustion Engineering supplied 10 inch Borg-Warner gate valves, nos. 3J-SIA-HV-684, 685, 687 and 688.
Evaluation ANPP has been advised by Combustion Engineering that the issue of incorrect material used as gate guides on certain motor-operated valves, supplied by Borg-Warner, was not the result of a sub-vendor error, but rather that of an in-house error.
Borg-Warner's investigation into the non-conforming gate guide material problem has lead them to conclude that the incident was an isolated case and is limited to the four valves listed above. This conclusion is based on a review, by Borg-Warner, of all valve shop orders requiring welded gate guides. The results of Borg-Warner's investigation found no discrepancies other than those identified above.
In addition Borg-Warner has also concluded that according to QA records no similar situation in which the use of incorrect material during the fabrication of nuclear valves, has occurred.
ANPP inspections of Unit 2 and 3 Safety Injection valves provides supplemental information and supports the conclusion by Borg-Warner that this was an isolated incident.
During the time these inspections were performed, Borg-Warner believed that the sub-vendor had supplied low alloy steel guides in lien of stainless steel as specified on the purchase order for 10 inch and 20 inch gate valves. The inspections were then limited to a sample which included four (4) Unit 2 valves (1-8", 1-10", and 2-20") and twenty (20)
Unit 3 valves (2-8", 10-10", 2-12", 2-14", and 4-20").
As described in ANPP-36697, dated May 29, 1986 - Interim Report, no additional Borg-Warner gate valves were found to have incorrect guide material.
Based on the above information, it is ANPP's position that this was an isolated incident and no further inspections are required.
DER 86 Final Report Page Two Root Cause The root cause of the deficiency was an isolated vendor error in that low alloy steel guides were inadvertently identified on the shop order with stainless steel part numbers and installed. It should be noted that the two part numbers are sequentially one digit apart, 77843-10 (SS) and 77844-10 (low alloy).
II.
Analysis of Safety Implications The four isolated valves found in Unit 3 to have low alloy steel guides are required to operate the shutdown cooling and containment spray systems.
The incorrect guide material could affect valve operability and the safe operation of the plant. This is based on a technical evaluation by ANPP that if the guides were left in the as-welded condition, with no stress relieving, it could result in the potential for cracking due to untempered martensite. The cracks could propagate from residual stresses or service stresses, or a combination of both.
The eventual condition could be a dislodged guide or part of a guide and this could affect valve operability.
Based on the above, this condition is evaluated as reportable under the requirements of 10CFR50.55(e) since, if it were to remain uncorrected it could represent a significant safety hazard.
l The project has also evaluated this condition as reportable under the requirements of 10CFR21.21(B)(3) and the report contains the required l
information with the exception of subpart (VI) regarding the number and location of such components supplied to other facilities.
A Copy of this report will be transmitted to CE for its evaluation under 10CFR part 21.
III. Corrective Action The guide rails of the four Unit 3 deficient valves 3J-SIA-HV-684, -685, l
-687 and -688 have been removed and replaced by rails of the correct material (Reference NCR SP-6408). The work was accomplished to original specification requirements using approved procedures.
Reference 1.
Letter V-CE-33651, April 15, 1986 2.
Letter B/CE-E-53291, May 5, 1986 3.
Letter V-CE-33731, May 7, 1986 4.
Letter V-CE-33822, June 3, 1986 l
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