Part 21 Report - 1997-801

ACCESSION #: 9710280289 Conval Inc. 285 FIELD ROAD, P.O. BOX 1049, SOMERS, CT 06071 PHONE 880-749-0761 FAX 860-763-3557 October 24, 1997 United States Nuclear Regulatory Commission Document Control Desk Fax: 301-816-5151 Washington, DC 20555 Subject: 10CFR-Part 21, Notification of Potential Safety Related Defect Dear Commissioners: This letter serves officially to notify the Commission of a potential safety-related defect in a basic component of five (5) valves supplied by Conval to three (3) nuclear power plants in the United States. The three (3) nuclear plants affected are: o Maine Yankee Atomic Power (3) Valves*_/ o Indiana & Michigan Power, D.C. Cook 1 & 2 (2) Valves*_/ *_/ All three (3) Maine Yankee Atomic Power Valves were unused and uninstalled as of October 22, 1997; a UPS Call Tag was issued October 24, 1997 for all three (3) valves to be returned to Conval. **_/ One (1) of these two (2) valves has been unused and uninstalled. The basic component addressed is the forged valve body of Conval's 1"- 1500# design, #5, Y-Globe, stop valve and check valve, which are identified as Conval's basic Fig.# 1.00-12G2J-S165F and Fig. # 1.00-12C2- S165F respectively. These valves are designed and manufactured by Conval to meet the requirements of ANSI/ASME B16.34. The body is forged to the requirements of ASME SA182-F316. The forgings were ordered as commercial grade items and dedicated for safety-related nuclear order use in accordance with Conval's Continued next page..... NRC 10CFR-Part 21 Notification - 316 Stainless Steel Forgings Page 2 of 3 October 24, 1997 dedication procedure, which is based on EPRI NP-5652 guidelines. Failure of the body forging in field service could lead to system leakage or possible body rupture. The forgings in question were produced by Ideal Forging Corporation, located at 165 Center Street, Southington, CT. Ideal produces these forgings in accordance with the material specification as defined by Conval's engineering specification. The information that led to the engineering investigation and reporting of this potential safety related defect was initiated on Sept. 22, 1997 by Conval's Quality Assurance Manager. The specific potential safety-related defect relates to a possible crack within the forging wall at the die flash line. The forgings affected are identified as Ideal Forge Heat Code Lot "M7", which is stamped on each body forging. During investigation of a valve failure with an "MT" body on a commercial order, it was determined that the forging process had generated the potential for an internal body wall defect condition neither detected by standard visual nor hydrostatic testing methods. After installation of that valve, operation at a pressure of 2200 psig and a temperature of 650 degrees F, and subsequent cool-down, a leak was detected through the body wall. The valve was removed from the system by the customer and returned to Conval for review and analysis. Laboratory analysis revealed that the cracked area of the forging contained oxides that could only have been generated at the forging temperature. The analysis also revealed that the failed body forging material flow was not optimal in the affected area. These two conditions were most likely caused by less than optimal forging temperatures. Analysis of other Ideal 316 stainless steel Heat Code lots and bodies forged from other materials causes us to conclude that the reportable problem is limited to this "M7" heat code lot. Ideal has taken corrective action steps to eliminate their processing problem. They have procured newer temperature monitoring devices at the forging area heating ovens. They have also instructed all foremen from the hammer forge areas on the cause of this defect. Ideal also conducted a re-creation experiment duplicating this defect. This defect was extremely difficult to re-create, which reinforced their conclusion that the defect was limited to the "M7" heat Code lot. NRC 10CFR-Part 21 Notification - 316 Stainless Steel Forgings Page 3 of 3 October 24, 1997 The three (3) nuclear plants affected have been notified of this potential safety-related defect verbally and in writing as of this date. These sites have been advised to remove the valves from service and return them to Conval for replacement of bodies, or replacement of whole valve assemblies if they desire. Due to the nature of the defect, Conval does not advise using any nondestructive testing methods to determine acceptability of body forgings in the field. If you have any questions and need additional information concerning this notification please contact me directly or Mr. David Boyden, Engineering Manager, immediately. Sincerely, CONVAL, INC. Edward N. Sharpless, President GENERAL INFORMATION or OTHER EVENT NUMBER: 33144 LICENSEE: CONVAL, INC. NOTIFICATION DATE: 10/24/97 CITY: SOMERS REGION: 1 NOTIFICATION TIME: 14:09 (ET] COUNTY: TOLLAND STATE: CT EVENT DATE: 10/24/97 LICENSE#: AGREEMENT: N EVENT TIME: 00:00[EDT] DOCKET: LAST UPDATE DATE: 10/24/97 NOTIFICATIONS CURTIS COWGILL RDO NRC NOTIFIED BY: EDWARD N. SHARPLESS GEOFFREY WRIGHT RDO HQ OPS OFFICER: STEVE SANDIN VERN HODGE NRR EMERGENCY CLASS: NOT APPLICABLE 10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH EVENT TEXT FIVE (5) CONVAL FORGED VALVE BODIES 1"-1500# DESIGN, #5, Y-GLOBE, STOP AND CHECK VALVE, WHICH ARE IDENTIFIED BY CONVAL'S BASIC FIG. # 1.00- 12G2J-S165F AND FIG. # 1.00-12C2-S165F SUPPLIED TO BOTH MAINE YANKEE ATOMIC POWER (3 VALVES) AND INDIANA & MICHIGAN POWER (D.C. COOK 1&2) (2 VALVES) MAY HAVE A DEFECT RELATED TO A POSSIBLE CRACK WITHIN THE FORGING WALL AT THE DIE FLASH LINE. ONLY ONE OF THE FIVE VALVES IS KNOWN TO BE INSTALLED AT THE D.C. COOK SITE. THE FORGINGS FOR THESE FIVE VALVES ARE IDENTIFIED AS IDEAL FORGE HEAT CODE LOT "M7", WHICH IS STAMPED ON EACH BODY FORGING. CONVAL DISCOVERED THE FORGING DEFECT DURING AN INVESTIGATION OF A VALVE RETURNED BY A CUSTOMER. IDEAL HAS TAKEN CORRECTIVE ACTION TO ELIMINATE THE PROCESSING PROBLEMS. THE AFFECTED NUCLEAR POWER PLANTS HAVE BEEN NOTIFIED BOTH VERBALLY AND IN WRITING. 265 Field Road, Somers, CT 06071-1049 Tel. 860-763-3551 ext. 201, FAX 860-763-3557 email: CONVAL, INC. Fax To: Untied States Nuclear Regulatory From: Edward N. Sharpless Commission Firm: Fax: 301-816-5151 Pages: 4 including cover Phone: 301-961-0550 Date: October 24,1997 Re: 10CFR-Part 21 Notification CC: D. Boyden, H. Smith [] Urgent [] For Review Please Comment [] Reply [] Please Recycle o Comments: The following three pages are a 10CFR-Part 21, Notification of Potential Safety Related Defect *** END OF DOCUMENT ***

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