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
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