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ACCESSION #: 9503020053 NTD-NRC-95-4403 Westinghouse Energy Systems (illegible print) Electric Corporation February 20, 1995 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Subject: Update to 10CFR21 Report Contained in Westinghouse Letter NTD- NRC-94-4320, dated 10/19/94 and Status Report Contained in Westinghouse Letter NTD-NRC-94-4361, dated 12/21/94 Reference: 1. Letter NTD-NRC-94-4320, N. J. Liparulo to Document Control Desk, 10/19/94 2. Letter NTD-NRC-94-4361, N. J. Liparulo to Document Control Desk, 12/21/94 3. Westinghouse Nuclear Safety Advisory Letter, NSAL-94- 023, 10/26/94 The following information is provided as an update to the 10 CFR 21 report that was previously identified to you in References 1 and 2. BACKGROUND Reference 1 identified a defect, as defined under 10CFR21, regarding the pressure reducing sleeve locknut of the JHF Model Safety Injection Pump that was manufactured by Ingersoll Dresser Pump (IDP) Company and supplied to several nuclear power plants by Westinghouse and IDP. Westinghouse also notified the affected licensees about the defect via Reference 3. Reference 1 indicated that IDP would perform a review of the applicable 400 series stainless steel parts and applicable heat treatments on other safety related pumps it supplied to the nuclear power industry to determine whether this situation could apply to other parts on other safety related pumps. This review was completed on December 15, 1994. Westinghouse notified the NRC about the results of this review via Reference 2. The results of the review indicated that the failure mechanism appears to be limited to IDP pump parts that consist of 416 SS, processed under IDP heat treatment process "HT 21"" and taken from IDP heat numbers #15899 and #28144. Also, the review indicated that additional pump parts may be susceptible to the same failure mechanism. Reference 2 indicated that IDP would determine whether the failure of the additional pump parts would prevent the applicable pump from performing its intended safety function. This review has been completed and indicates that some of the additional pump parts may also constitute a defect, as defined in 10 CFR 21, which could create a substantial safety hazard. The following report provides more information about these additional pump parts. EVALUATION IDP's evaluation results indicate that all 416 SS parts processed under IDP heat numbers #15899 and #28144 are susceptible to the same failure mechanism as the pressure reducing sleeve locknuts. These parts have been divided into three categories. The first category includes parts which were supplied with the original pump assembly and whose failure could prevent the pump from performing its intended safety function. These parts and the applicable plants are identified in Table 3. Also, note that these parts include the pressure reducing sleeve locknuts that were the parts originally identified in Reference 1. The second category includes parts which were supplied with the original pump and whose failure would not prevent the pump from performing its intended safety function. These parts are identified in Table 4. The parts should be replaced as a prudent maintenance activity. It should be emphasized that these parts do not constitute defects pursuant to 10 CFR 21 since the failure of the parts should not prevent the pump from performing its intended safety function. However, they are included in this letter to identify the results of the evaluations that are mentioned in References 1 and 2. The third category includes the parts which were supplied as replacement pump parts and whose failure could prevent the pump from performing its intended safety function. Most of the replacement parts were supplied directly to the utilities by IDP. These parts and the applicable plants are identified in Table 5. Please note that Table 5 has been divided into two lists. One list ("Parts from Identified Material") includes the replacement parts that are known to have been taken from heat #15899 and #28144. The other list ("Parts from Unidentified Material") includes those parts which could have been manufactured from either heat #15899 or #21844, based on the time of manufacture original material specification and part size. However, there is no documentation to specifically identify the heat number from which the part was taken. Therefore, it was assumed that the parts were taken from heat #15899 and #21844. The identification of the parts in Tables 3, 4 and 5 is based on several reported part failures, a failure analysis of failed parts and engineering judgement. Duke Power Company reported two separate failures (cracking) of the pressure reducing sleeve locknuts on JHF model safety injection pumps. Both locknuts consisted of 416 SS and were processed under heat #15899. Duke Power performed a failure analysis on each locknut. The failure analysis indicated that the failure mechanism was stress corrosion cracking. The analysis also indicated that each locknut's susceptibility to stress corrosion cracking was increased by a relatively high martensite phase harness which allegedly resulted from an insufficient tempering operation. A comparison of the Duke Power Failure analysis report and the IDP heat treatment specification and heat material certification is provided in Table 1. Table 1: Pressure Reducing Sleeve Locknut - Comparison of Duke Power Company Failure Analysis to IDP Heat Treatment Specification and Material Certification Hardness (Re) First Locknut Second Locknut Failure Analysis - Bulk Phase 35 32-33 Failure Analysis - Microhardness 45-49 42-44 Heat Treatment "HT21" Specification 27-32 Heat #15899 Material Certification Bulk Phase Hardness 27 The existence of two failures and the data in Table 1 provide a basis to conclude that the locknuts are defects as defined in 10 CFR 21. First, it should be noted that 400 series SS with a hardness of greater than 40 Rc is very susceptible to intergranular stress corrosion cracking in aqueous environments. Table 1 indicates that for both locknuts, the microhardness was higher than 40 Rc. Also, Table 1 indicates that for both locknuts, the bulk phase hardness measured in the failure analysis was significantly higher than the bulk phase hardness provided on the material certification sheet. It could not be determined why these bulk phase hardness values are different. Sine, the microhardness was greater than 40 Rc, the bulk phase hardness difference could not be attributed to any specific reason. However, since the cracking was observed on each locknut, it was determined that all parts from heat #15899 could be susceptible to the same failure. In addition to the above, Duke Power Company recently discovered cracking on a spacer sleeve in another JHF model safety injection pump. The spacer sleeve consisted of 416 SS and was processed under IDP heat treatment specification "HT 21". However, the spacer sleeve was taken from a different heat which was heat, which was heat #28144. Duke Power performed a failure analysis on the spacer sleeve and determined that the failure mechanism was also stress corrosion cracking. Also, the failure analysis indicated that the spacer sleeve's hardness made the sleeve marginally acceptable for service in aqueous environments. A comparison of the Duke Power Failure analysis report and the IDP heat treatment specification and heat material certification for the spacer sleeve is provided in Table 2. Table 2. Impeller Spacer Sleeve - Comparison of Duke Power Company Failure Analysis to IDP Heat Treatment Specification and Material Certification Hardness (Rc) Failure Analysis - Bulk Phase 26-30 (1)_/ Failure Analysis - Microhardness 33-39 Heat Treatment "HT21" Specification 27-32 Heat #21844 Material Certification - 27 Bulk Phase Hardness The existence of the cracked spacer sleeve and the data in Table 2 provide a basis to conclude that the spacer sleeve is a defect as defined in 10 CFR 21. First, the measured microhardness of 33-39 Rc is higher than the material certification value of 27 Rc. It is less than 40 Rc, but nonetheless is marginally susceptible to stress corrosion cracking in aqueous environments. The bulk phase hardness range is somewhat higher than the material certification value, but it is still within the heat treatment specification range of 27-32 Rc. Based on this information, it was concluded that all parts used from heat #28144 could be susceptible to the same failure mechanism. Finally, and as mentioned, Tables 1 and 2 indicate that there is some difference between the bulk phase hardness and the material certification values. There are no apparent reasons for these differences. Furthermore, Tables 1 and 2 indicate that there are significant differences between the bulk hardness and the microhardness values. There are no apparent reasons for these differences; however, it may be postulated that the differences are attributable to insufficient tempering. IDP has _____________________________ (1)_/ This value was determined from the uncracked spacer sleeve on the same pump. Both the uncracked and cracked sleeves were taken from Heat #28144. not received any additional reports of part failures involving 416 SS under heat treatment specification "HT21." Therefore, it was concluded that the failures should be limited to only those parts that were taken from heats #15899 and #21844. Table 3 identifies all pump parts that were originally supplied with a pump, taken from heat #15899 and #28144 and whose failure could prevent the applicable pump from performing its intended safety function. Table 4 identifies the parts that were originally supplied with a pump, taken from heat #15899 and #28144 and whose failure would not prevent the pump from performing its intended safety function. However. it is recommended that the plan in Table 4 be replaced as a prudent maintenance practice. Finally, Table 5 identifies the replacement pump parts that were either supplied or believed to have been supplied from heat #15899 and 28144 and whose failure could prevent the applicable pump from performing its intended safety function. SAFETY SIGNIFICANCE The safety significance for the failure of each part identified in Tables 3, 4 and 5 is provided as follows. The failure of the parts in Tables 3 and 5 could prevent the pump from operating. For Table 4, the part failure should not prevent the pump from operating. More detailed information for the parts identified in Tables 3, 4 and 5 will be provided directly to each utility. The pumps identified in Table 3 are all JHF model safety injection pumps. These pumps are used in the intermediate head safety injection system for the applicable plants. The loss of these pumps during the short term mitigation period of a loss of coolant accident (LOCA) would impair the plant's ability to mitigate the consequences of the LOCA. The loss of the pump (or pumps) would reduce the overall flow to the core, which could create a condition that is a substantial safety hazard. The pumps identified in Table 5 include the intermediate head safety injection, auxiliary feedwater, and charging/safety injection pumps. The intermediate head pumps are discussed above. The auxiliary feedwater pumps are used to provide feedwater to the steam generators during certain accident conditions. The loss of these pumps during a feedwater line break accident would impair the plant's ability to recover from the break. The loss of the pump (or pumps) would reduce the available secondary side cooling, which could create a condition that is a substantial safety hazard. The charging/safety injection pumps are used in the high head safety injection system for the applicable plants. The loss of these pumps during the short term mitigation phase of a LOCA would impair the plant's ability to mitigate the consequences of the LOCA, especially for a small break LOCA. The loss of the pump (or pumps) would reduce the overall flow to the core, which could create a condition that is a substantial safety hazard. RECOMMENDATIONS The following recommendations are proved for this issue. 1. Review Tables 3, 4 and 5 to determine whether the plant has any parts that could be affected by this failure mechanism. The parts identified in Table 3 and 5 are considered defects as defined in 10 CFR 21. Although the parts in Table 4 are not considered defects pursuant to 10 CFR 21, the parts in Table 4 should eventually be replaced as a prudent maintenance practice since these parts are susceptible to the same failure mechanism. 2. Compare the information for the part in Tables 3, 4 and 5 to determine whether the part is currently installed on the pump. In some cases, this part may have been changed after the part was supplied. 3. For parts in Table 3 and 5, if it is determined that the pump part is currently installed on the pump, then the following should be considered. First, as indicated in Table 5, if the affected part is a shaft sleeve compression nut or a shaft sleeve collar, the part can be inspected for cracking without disassembly of the pump. Alternatively, if the affected part can not be inspected without disassembly of the pump and it is not practical to immediately disassemble the pump, then the pump operating history should be reviewed relative to the mechanism for stress corrosion cracking. The mechanism for stress corrosion cracking is dependent upon several factors including, but not limited to, the amount of stress placed on the part, the time the part is exposed to that stress, the time exposed to an aqueous environment and the physical dimensions of the part. By reviewing these factors, it may be possible to demonstrate that the part failure is not imminent and/or that the part will not fail in a manner that will prevent the pump from performing its intended safety function. However, it is ultimately recommended that the part be replaced with the part currently recommended by IDP. The above information is being concurrently transmitted to affected utilities via supplement to Westinghouse letter NSAL-94-023. If you have any questions regarding this transmittal, please contact H. A. Sepp of my staff on 412/374-5282. Very truly yours, N. J. Liparulo Manager Nuclear Safety Regulatory and Licensing Activities JWF/p cc: R.E. Joines/IDP G. Morrissey/IDP Table 3 "ORIGINAL CONSTRUCTION PUMP PARTS FROM HEAT #15899 AND #28144," 2 pages omitted. Table 4 "ORIGINAL CONSTRUCTION PUMP PARTS FROM HEAT #15899 AND #28144, REPLACEMENT OF PART IS NOT MANDATORY," 2 pages omitted. Table 5 "REPLACEMENT PUMP PARTS FROM HEAT #15899 AND #28144," 2 pages omitted. GENERAL INFORMATION or OTHER EVENT NUMBER: 28412 LICENSEE: WESTINGHOUSE ELECTRIC CORPORATION NOTIFICATION DATE: 02/20/95 CITY: PITTSBURGH REGION: 1 NOTIFICATION TIME: 10:30[ET] COUNTY: STATE: PA EVENT DATE: 02/20/95 LICENSE#: AGREEMENT: N EVENT TIME: 10:00 [EST] DOCKET: LAST UPDATE DATE: 02/20/95 NOTIFICATIONS NRC NOTIFIED BY: H SEPP HQ OPS OFFICER: JOHN MacKINNON EMERGENCY CLASS: NOT APPLICABLE 10 CFR SECTION: CDEF 21.21(b)(2) DEFECTS/NONCOMPLIANCE EVENT TEXT THE FOLLOWING IS A PARTIAL TEXT OF A FACSIMILE FROM WESTINGHOUSE ELECTRIC CORPORATION, PITTSBURGH, PA. THIS PART 21 PERTAINS TO AN IDENTIFIED PRESSURE REDUCING SLEEVE LOCKNUT DEFECT FOR JHF MODEL SAFETY INJECTION PUMP MANUFACTURED BY INGERSOLL DRESSER PUMP (IDP) COMPANY. THIS FACSIMILE IS AN "UPDATE TO 10CFR21 REPORT CONTAINED IN WESTINGHOUSE LETTER NTD-NRC-94-4320, DATED 10/19/94 AND STATUS REPORT CONTAINED IN WESTINGHOUSE LETTER NTD-NRC-94-4361, DATED 12/21/94. REVIEW HAS BEEN COMPLETED AND INDICATES THAT SOME OF THE ADDITIONAL PUMP PARTS MAY ALSO CONSTITUTE A DEFECT, AS DEFINED IN 10CFR21, WHICH COULD CREATE A SUBSTANTIAL SAFETY HAZARD. IDP's EVALUATION RESULTS INDICATE THAT ALL 416 SS PARTS PROCESSED UNDER IDP HEAT NUMBERS # 15899 AND # 28144 ARE SUSCEPTIBLE TO THE SAME FAILURE MECHANISM AS THE PRESSURE REDUCING SLEEVE LOCKNUTS." THIS ELEVEN PART FACSIMILE CALLS OUT THE FOLLOWING REACTOR PLANTS USING PARTS FROM HEAT # 15899 & HEAT # 28144. KANSAI OHI 1 & 2; TVA, WATTS BARR 1 & 2; DUKE POWER, MCGUIRE 1 & 2, CATAWBA 1 & 2; COMMONWEALTH EDISON, BRAIDWOOD 1 & 2, BYRON 1 & 2, WOLF CREEK NUCLEAR OPERATING COMPANY, WOLF CREEK. FOLLOWING REACTOR PLANTS COULD BE USING THE DEFECTIVE PARTS FROM THE HEAT NUMBERS LISTED ABOVE. ALABAMA POWER, FARLEY 2, COMMONWEALTH EDISON, ZION 1, CONSOLIDATED EDISON, INDIAN POINT, DUQUESNE LIGHT, BEAVER VALLEY 1, INDIANA MICHIGAN POWER, COOK 2, KANSAI ELECTRIC, OHI 1 & 2, NORTHERN STATES POWER, PRAIRE ISLAND 1 & 2, PORTLAND GENERAL ELECTRIC, TROJAN, PACIFIC GAS & ELECTRIC, DIABLO CANYON 2, AND PUBLIC SERVICE ELECTRIC AND GAS, SALEM 1 & 2. (Continued on next page) LICENSEE: WESTINGHOUSE ELECTRIC PAGE # 2 OF EVENT NUMBER: 284 FACSIMILE SENT TO WALTER HAASS. *** END OF DOCUMENT ***