Part 21 Report - 1998-211

ACCESSION #: 9803170065 LICENSEE EVENT REPORT (LER) FACILITY NAME: Diablo Canyon Unit 2 PAGE: 1 OF 9 DOCKET NUMBER: 05000323 TITLE: Defect in Class 1 Piping Spool EVENT DATE: 12/17/97 LER #: 98-001-00 REPORT DATE: 03/09/98 OTHER FACILITIES INVOLVED: DOCKET NO: 05000 OPERATING MODE: 1 POWER LEVEL: 100 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR SECTION: OTHER 10 CFR 21 (d)(3)(ii) LICENSEE CONTACT FOR THIS LER: NAME: Vickie A. Backman - Senior Regulatory TELEPHONE: (805) 545-4289 Services Engineer COMPONENT FAILURE DESCRIPTION: CAUSE: SYSTEM: COMPONENT: MANUFACTURER: REPORTABLE NPRDS: SUPPLEMENTAL REPORT EXPECTED: NO ABSTRACT: On December 17, 1997, PG&E identified that an ASME Class 1 piping spool had not been cleaned after fabrication by Consolidated Power Supply (CPS). Cleaning is required for SA-376 type material in accordance with ASME Section II to assure proper passivation and corrosion resistance. The piping spool had been shipped from CPS to PG&E after it had been bent, solution annealed, tested, and upgraded from commercial grade to ASME Class 1. The piping spool was accepted by PG&E during receipt inspection but had not been installed in the plant. PG&E had ordered the specially fabricated piping spool for use in a high-head safety injection system cold leg injection branch line. This condition was determined to be a defect under 10 CFR 21. On February 6, 1998, PG&E notified the NRC of the defect in accordance with 10 CFR 21.21(d)(3)(i). The failure to meet ASME cleaning requirements was caused by the lack of clear technical requirements in the PG&E purchase order (PO) and failure of the CPS order entry and evaluation process to formally document and communicate errors or needed clarifications in the PO. Corrective actions include cleaning and upgrading the piping spool to proper requirements, providing additional procurement guidance, and an audit and follow up assessment of CPS. END OF ABSTRACT TEXT PAGE 2 OF 9 I. Plant Condition Unit 2 was in Mode 1 (Power Operations) at 100 percent power. II. Description of Problem A. Summary On December 17, 1997, PG&E identified that an ASME Class 1 piping spool (PSP) had not been cleaned after fabrication by Consolidated Power Supply (CPS). Cleaning is required for SA-376 type material in accordance with ASME Section II to assure proper passivation and corrosion resistance. The piping spool had been shipped from CPS to PG&E after it had been bent, solution annealed, tested, and upgraded from commercial grade to ASME Class 1. The piping spool was accepted by PG&E during receipt inspection but had not been installed in the plant. PG&E had ordered the specially fabricated piping spool for use in a high-head safety injection system (SIS)(BP) cold leg injection branch line. This condition was determined to be a defect under 10 CFR 21. On February 6, 1998, PG&E notified the NRC of the defect in accordance with 10 CFR 21.21 (d)(3)(i). B. Background The piping spool is ASME Class 1, schedule 160, 304 seamless stainless steel. It is 1.5 nominal pipe size (NPS), approximately 59 inches in length. The spool is one of a kind and was fabricated to fit within the existing piping configuration. ASME Section II, 1989 Edition, SA-376, paragraph 11.8, "Workmanship, Finish, and Appearance," states, in part, that "The pipe shall be free of scale and contaminating iron particles." The cleaning process is required after bending and solution annealing to assure passivation and corrosion resistance. C. Event Description In August 1997, the Procurement Specialist Group (PSG) received a request from Diablo Canyon Power Plant (DCPP) Outage Services for an ASME Class 1 piping spool. The piping spool was to be installed in the SIS as part of a design change. TEXT PAGE 3 OF 9 In September 1997, the PSG developed a material requisition and purchase order (PO) by collecting technical and quality requirements applicable to the design requirements for the piping spool. On September 22, 1997, PG&E issued a PO which indicated that CPS was to supply three items. Item 3 was one piping spool, specified by the following: o 1.5 NPS, 304 stainless steel, seamless with bend o ASME # SA-376 TP 304 o ASME Section III, Subsection NB The spool was to be dimensioned and bent in accordance with an attached PG&E sketch. The PO included a standard clause which stated "ASME III - Subsection NB requirements, 1989 Edition item shall be fabricated in accordance with the ASME Boiler & Vessel Code, Section III, Subsection NB, 1989 Edition, no addenda." The PO also indicated that heat treatment should be performed in accordance with a PG&E construction specification. However, a pertinent section of the specification which identified cleaning requirements for the piping spool was inadvertently omitted from the PO. On October 13, 1997, CPS generated a PO to procure the piping spool as commercial grade. The pipe was bent by Tulsa Tube Bending, solution annealed by Lindberg Heat Treating, and tested by Laboratory Testing Inc. In mid-November 1997, during a visit to DCPP, a CPS representative informed several PG&E representatives that the piping spool would be discolored when it arrived at DCPP. However, PG&E personnel did not recognize that the piping spool's appearance could have adverse affects on corrosion resistance. The potential problem was not documented nor pursued by either PG&E or CPS. On December 10, 1997, CPS certified the piping spool to ASME Section III, Class 1, 1989 Edition, no addenda, and ASME Section II, 1989 Edition, no addenda. No deviations were identified on the Certificate of Conformance (COC). CPS shipped the piping spool to TEXT PAGE 4 OF 9 PG&E with a dark and scaled appearance, which indicated that the piping spool had not been cleaned and allowed to passivate as required by ASME Section II, SA-376. On December 12, 1997, the piping spool was accepted during receipt inspection and sent to the field for installation. On December 17, 1997, during pre-installation fit up activities, a welder questioned the pipe's appearance and the condition was documented on a corrective action document. On January 8, 1998, a Nuclear Quality Services audit team recognized the importance of the issue, initiated a nonconformance report and established a multi-disciplined Technical Review Group to evaluate and disposition the condition. On January 27, 1998, PG&E sent a letter to CPS requesting a formal evaluation of the piping spool for reportability under 10 CFR 21. The letter stated that the evaluation was warranted based on the condition of the supplied piping spool and the certification from CPS which indicated the piping spool met ASME Section II, 1989 Edition, no addenda. On February 2, 1998, PG&E received a letter from CPS which indicated they believed that the supplied material met the PG&E PO requirements. The letter further indicated that the CPS quality review had determined that the PG&E PO had over ridden some of the requirements of the material specification. The letter indicated that a 10 CFR 21 evaluation had not been performed at the time because CPS believed the PO requirements had been met and that they did not have design responsibility, capability, or expertise to evaluate a specific application for the material. On February 6, 1998, the PG&E operations shift foreman notified the NRC of the defect in accordance with 10 CFR 21.21 (d)(3)(i). D. Inoperable Structures, Components, or Systems that Contributed to the Event None. TEXT PAGE 5 OF 9 E. Dates of Major Occurrences 1. December 17, 1997: Date of discovery that a deviation from ASME requirements existed. 2. February 6, 1998: Responsible officer informed that a defect existed. 3. February 6, 1998: PG&E notified the NRC of a reportable defect in accordance with CFR 21.21(d)(3)(i). F. Other Systems or Secondary Functions Affected None. G. Method of Discovery The condition was identified by a utility welder during pre-installation activities. H. Operator Actions None. I. Safety System Responses None. III. Cause of the Problem A. Immediate Cause The condition was caused by the failure to clean the piping spool after cold bending and solution annealing. The lack of cleaning prevented the formation of a passive layer which assures adequate corrosion resistance. TEXT PAGE 6 OF 9 B. Root Causes Failure to meet ASME cleaning requirements was caused by: 1. The lack of clear technical requirements in the PG&E PO; and 2. Failure of the CPS order entry and evaluation process to formally document and communicate errors or needed clarifications in the PO. C. Contributory Causes 1. The PSG engineers lacked knowledge of the ASME requirements unique to this non-routine procurement. 2. Sections from the PG&E construction specification were included in the PO based on inputs from PSG. However, the specification was not part of the design change package requirements and was added to the PO contrary to procedure requirements. A paragraph from the specification which addressed cleaning was not included in the PO package received by CPS. 3. The COC from CPS did not indicate any deviations from requirements because they believed they had satisfied PO specifications. Had the deviations from the material specifications been identified on the COC, the piping spool would have been identified as nonconforming during receipt inspection. 4. Because of the lack of technical requirements regarding cleaning in the PO or receiving inspection instructions, the PG&E receipt inspector did not have sufficient guidance to identify the piping spool as nonconforming. IV. Analysis of the Event This event had no actual safety significance because the piping spool had not been installed in the plant. The lack of cleaning would have prevented a strong passive layer from forming on the pipe. This layer is essential to corrosion resistance. The most likely corrosion mechanism would have been pitting or crevice corrosion. TEXT PAGE 7 OF 9 If the spool had been installed in the plant without the passive layer established, either mechanism could have penetrated the pipe wall in a relatively short time. PG&E believes the wall could have been penetrated within 5 years. PG&E postulated that a worm hole-like pit could develop in the pipe wall. Once the hole developed, borated water would leak from the pipe. A small leak during normal power operation would have been detected in a short period of time (approximately two weeks. However, if the leak went undetected, it could have diverted enough injection flow to place the emergency core cooling system outside its design basis. If this scenario is evaluated against the criteria for determining a substantial safety hazard as defined in 10 CFR 21, the leak could have resulted a loss of safety function necessary to mitigate the consequences of the accident in a postulated design basis accident (loss-of-coolant accident) due to other causes. However, since the piping spool was not installed in the plant, there was no adverse affect on the health and safety of the public. V. Corrective Actions A. Immediate Corrective Actions 1. The piping spool was returned to CPS. The PO was revised to clearly specify cleaning requirements. The piping spool was cleaned by CPS and returned to PG&E in accordance with the PO. 2. PG&E performed tests and inspections on the clean piping spool to verify that it met appropriate code requirements. 3. The piping spool was installed on February 25, 1998, during the ongoing Unit 2 refueling outage. The line will be checked during a flow balance prior to entering Mode 4 (Hot Shutdown) and leak tested prior to entering Mode 2 (Startup). 4. Tailboard discussions were held for procurement and inspection personnel involved with ASME procurements. TEXT PAGE 8 OF 9 5. An audit was completed by PG&E at the CPS facility during the week of February 9, 1998. The PG&E auditor concluded that the missing pages from the PG&E PO were not formally addressed or documented by CPS personnel. This deficiency led to the oversight which allowed the piping spool to be sent to PG&E in an unacceptable condition. 6. CPS documented the deficient condition and administered training to their sales, order entry quality assurance, and receipt inspection personnel. B. Corrective Actions to Prevent Recurrence 1. The PSG will develop additional guidance for procurement personnel to assure the proper level of detail is identified on POs for ASME requisitions. The guidance will be approved by August 31, 1998. 2. PG&E is testing a sample of safety related material received from CPS to verify that ASME requirements are being met. In addition, the Nuclear Procurement Issues Committee (NUPIC) is tentatively scheduled to perform an audit of CPS in September 1998. Based on the results of the material testing and audit results, PG&E will reassess for need for additional actions. The assessment will be completed within 60 days of the completed NUPIC audit. VI. Additional Information A. Name and address of the individual or individuals informing the Commission: Gregory M. Rueger - Senior Vice President and General Manager, Nuclear Power Generation Pacific Gas and Electric Company Mail Code N9B Box 770000 San Francisco, CA 94177 TEXT PAGE 9 OF 9 B. Identification of the firm constructing the facility Or supplying the basic component which fails to comply or contains a defect The piping spool was supplied by: Consolidated Power Supply 3556 Mary Taylor Road Birmingham, Al. 35235 C. Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees. None. D. Previous LERs on Similar Problems None. ATTACHMENT TO 9803170056 PAGE 1 OF 1 DRAFT REVISION: X FILE LOCATION: S:\RS\GRP_WORK\ler\1998\29800100 THIS IS A COMMITMENT TRACKING MEMO (Remove prior to NRC submittal) Document: PG&E Letter DCL-98-030 Subject: Licensee Event Report 2-98-001-00 Defect in Class 1 Piping Spool Commitment #1 - The PSG will develop additional guidance for procurement personnel to assure the proper level of detail is identified on POs for ASME requisitions. The guidance will be approved by August 31, 1998. Responsibility: John Sopp ECD August 31, 1998. Department: PTPE Tracking Document: NCR 2046 Action, 11. ADDED TO NCR by tlh Outage Related? No Commitment Type: Firm PCD Commitment? Yes Estimated Cost: < $15,000 Nature of Cost: one-time Commitment # 2 - PG&E is testing a sample of safety related material received from CPS to verify that ASME requirements are being met. In addition, the Nuclear Procurement Issues Committee (NUPIC) is tentatively scheduled to perform an audit of CPS in September 1998. Based on the results of the material testing and audit results, PG&E will reassess for need for additional actions. The assessment will be completed within 60 days of the completed NUPIC audit. Responsibility. Mike Jacobson ECD October 1, 1998 Department: SQCP Tracking Document. NCR 2046 Action 12. ADDED TO NCR by tlh Outage Related? No Commitment Type: Firm PCD Commitment? No Estimated Cost: < $15,000 Nature of Cost: one-time *** END OF DOCUMENT ***

Page Last Reviewed/Updated Tuesday, March 09, 2021