United States Nuclear Regulatory Commission - Protecting People and the Environment


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 ***





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