ML20079F256
| ML20079F256 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Diablo Canyon |
| Issue date: | 02/25/1982 |
| From: | Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| Shared Package | |
| ML20079F227 | List: |
| References | |
| FOIA-83-363, TASK-PINV, TASK-SE SECY-82-081, SECY-82-81, NUDOCS 8203120423 | |
| Download: ML20079F256 (81) | |
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%,~....f POLICY ISSUE February 25, 1982 (Notation Vote)
SECY-82-81 For:
The Commissioners From:
William J. Dircks Executive Director for Operations
Subject:
ABNORMAL OCCURRENCE RECOMMENDATION - SEISMIC DESIGN ERRORS AT DIABLO CANYON NUCLEAR POWER PLANT Purcose:
Approval of an abnormal occurrence deternination.
Discussion:
Enclosed is a draft Federal Register notice describing as an abnomal occurrence tne seismic design errors at the Diablo Canyon Nuclear Power Plant with the subsequent suspension of the fuel load and low-power operating license of Unit 1 on November 19, 1981.
This item is proposed for reporting based on one of the
' general criteria of the Abnomal Occurrence Policy Statement; i.e., major deficiencies in aanagement controls for licensed facilities can be considered an abnormal occurrence.
Deficien-cies were iuentified by investigation of the seismic design errors which went unnoticed for several years, were of a type that propagated, and were in an area of major safety concern, i.e., seismic design.
Recommendation:
That the Commissich:
1.
Approve the subject proposed abnormal occurrence together with its associated Federal Register Notice and 2.
Note that following approval, the Office of Congressional
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Affairs will notify the appropriate Congressional Committees of the intent to publish the Federal j
Register Notice.
XA Copy Has-8 en krif Io POR CONTACT:
J. Crooks /P. Bobe 192d!25/492-4426
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'.....g POLICY ISSUE February 25. 1932 (Notation Vote) sr.cy-82-81 For:
The Commissioners From:
William J. Dircks Executive Director for Operations Subject :
ABNORMAL OCCURRENCE RECOMMENDATION - SEISHIC DESIGN ERRORS AT DIABLO CANYON NUCLEAR POWER PLANT Purcose:
Approval of an abnormal occurrence determination.
Discussion:
Enclosed is a draft Federal Register notice describing as an abnormal occurrence tne seismic design errors at the Diablo Canyon Nuclear Power Plant with the subsequent suspension of the fuel load and low-power operating license of Unit 1 on November 19, 1981.
This item is proposed for reporting based on one of the
' general criteria of the Abnormal Occurrence Policy Statement; i.e., major deficiencies in management controls for licensed facilities can be considered an abnormal occurrence.
Deficien-cies were identified by investigation of the seismic design errors which went unnoticed for several years, were of a type that propagated, and were in an area of major safety concern, i.e., seismic design.
Recommendation:
That the Commission.
i 1.
Approve the subject proposed abnomal occurrence together with its associated Federal Register Notice and
)
2.
Note that following approval, the Office of Congressional Affairs will notify the appropriate Congressional Committees of the intent to publish the Federal Register Notice.
XA Copy _Hos-Been knf to PDR CONTACT:
J. Crooks /P. Bobe 192-4425/492-4426 hjf
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- Scheduling:
While no specific circumstances require Commission Action by a particular date, it is desirable to disseminate j
abnormal occurrence information to the public as soon as possible.
It is expected that Commission action within two weeks of receipt of this draft proposal would permit publication in the Federal Register about 10 days later.
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William 0. Dircks Executive Director for Operations
Enclosure:
Oraft Federal Register Notice Commissioners' comments should be provided directly to the Office of the Secretary by c.o.b. Friday, March 12, 1982.
Commission Staff Office comments, if any, should be submitted to the Commissioners NLT March 5, 1982, with an information copy to the office of the Secretary.
If the paper is of such a nature that it recuires additional time for analytical review and comment, the Commissioners and the Secretariat should be apprised of when comments may be expected.
DISTFIBUTION:
Commissioners Commission Staff Offices EDO EID ACRS ASL3P e
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[7590-01]
NUCLEAR REGULATORY COMMISSION ABNORMAL OCCURRENCE SEISMIC OESIGN ERRORS AT DIABLO CANYON NUCLEAR POWER PLANT Section 208 of the Energy Reorganization Act of 1974, as amended, requires the NRC to disseminate information on abnonnal occurrences (i.e., unscheduled incidents or events which the Commission determines are significant from the standpoint of public health and safety). The following incident was determined to be an abnomal occurrence using the criteria published in the Federal Register on February 24,1977 (42 FR 10950). One of the general criteria notes that major deficiencies in management controls for licensed facilities can be considered an abnormal occurrence. The following description of the incident also contains the remedial actions taken to date.
' Date and Place - On September 28, 1981 and September 30, 1981, Pacific Gas and Electric (PG&E) submitted letters to the NRC stating that certain drawings (' diagrams") used in the seismic design in the Diablo Canyon Unit 1 containment annulus area.were in error.
The diagrams used were applicable to Diablo Canyon Unit 2, but were identified for use in the Unit 1 seismic design.
Subsequent investigation into this issue revealed aaditional design errors.
This resulted in suspension of the Diablo Canyon Unit 1 fuel load and low-power operating license on November 19, 1981.
Licensee DPR-76 had been issued on September 22,19&l, and authorized fuel loading and the conduct of tests at up to five percent of rated power at Diablo Canyon Unit No. 1.
(Unit 2 was still under construction and had not yet received an operating license).
Diablo Canyon Units 1 and 2 4
utilize pressurized water reactors and are located in San Luis Obispo County, California.
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[7590-01]
- Nature and Probable Consecuences - On September 21, 1981, an engineer employed by PGAE in the hanger design group, was performing work for Diablo Canyori Unit 2 in response tio NRC IE Bulletin NO, 79-14 (" Seismic Analysis for As-Built Safety-Related Piping Systera:").
This work
. involved the use of diagrams of the containment building annulus The engineer became suspicious that the supposedly Unit 2 diagrams area.
did not accurately represent Unit 2 structural configuration.
On September 21-22, 1981, he continued to investigate this apparent dis-crepancy and brought it to the attention of his immediate supervisor.
On September 24, the responsible Senior Civil Engineer had been informed of the apparent discrepancy.
On September 25, second level PG&E management were notified and they in turn contacted their seismic design contractor, URS/ John A. Blume and Associates (URS/Blume).
URS/Blume confirmed that the wrong diagrams had been used.
On September 26, PG&E management continued to evaluate the problem.
On September 27, the Plant Superintendent notified the NRC Senior Resident Inspector tha' t a problem did indeed exist.
14RC investigation into the situation disclosed the followirg:
(1)
The diagrams were developed at PG&E and apparently given to URS/Blume on March 8,1977 for their use in the developmer,t of vertical seismic response spectra for the Unit 1 and Unit 2 containment building annulus areas.
(2) URS/Blume, when given the diagrams, knew the diagrams were applicable to Unit 2.
However, they were not aware that the Unit 1 and Unit 2 con-tainment annulus areas are mirror images.
Therefore, during the
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development of the associated seismic response spectra, URS/Blume assumed that both Unit I and Unit 2 containment buildings were of the saine configuration.
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(3) PG&E, upon receipt of the seismic response spectra in May 1977 and July 1977, developed by URS/Blume, assumed the spectra and associated containment annulus frame orientation diagrams were for the Unit 1 containment since it was identified as such by URS/Blume.
In actuality, the containment annulus frame orientation diagrams represented the Unit 2 containment.
PG&E, in turn, cerformed subsequent design calcu-lations for Unit i using Unit 2 frame orientation diagrams.
PG3E then, i
knowing that Unit 2 containment was a mirror image of Unit 1, " flipped" the diagram for use in performing design calculations for Unit 2.
PG&E, thus in turn, erroneously used Unit 1 containment annulus frame orientation diagrams for the development of Unit 2 design requirements.
Upon confirmation that wrong diagrams were used in the development of Unit 'l desirt requirements,.PG&E initiated a re-analysis effort of structures, equipment and components in the containment annulus using the appropriate containment annulus frame orientation diagrams.
These initial reanalyses indicated that, as a ' result of the error, modifications were required 4
to be made on a number of Unit 1 pipe ' supports. These modifications involved such actions as adding snubbers, ~ changing the snubbe,r size, adding braces, replacing structural members, and stiffening base plates.
Subsequent investigations by the NRC, and design reviews by PG8E and their consultant have identified a number of additional design concerns.
These include:
failure to use the latest revision of the vertical response spectra in design of conduit and cable tray suppo' ts; incorrect weight r
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[7590-01] distribution used to determine the containment annulus vertical seismic response spectral curves; erroneous spectra used to complete the safety injection piping problem; and two small bore piping snubbers required by seismic analyses were not designed or installed. The design reviews are continuing at this time.
Cause or Causes - The problem related to the use of the wrong diagrams appears to have been caused by the informal manner in which certain data were developed by PG&E and transmitted to URS/81ume and the lack of independent review of these data within PG&E prior to submittal to URS/Blume.
Identification of the additional design errors indicates a more general failing in the licensee's design quality coItrols for service type contractors.
Actions Taken to Prevent Recurrence Licensee - At the end of September 1981, the licensee verbally requested the services. of a consultant, R. L. Cloud Associates, Inc. (R. L. Cloud) to conduct a seismic design review to determine tf other errors had been made-in the' seismic design of Diablo Canyon Unit 1.
This request was subsequently formalized by the licensee with the issuance of a contract to R. L. Cloud.
NRC - In October 1981, the NRC conducted a special inspection (NUREG 0862, Issue 1) at the PG&E URS/Blume offices in San Francisco, California to evaluate the quality assurance programs and other management control systems in effect at PG!.E and at URS/Blume during the period from 1970 to present; the extent to which these quality assurance programs and management control systems were implemented as they relate to the development, transmittal, and use of safety-related design informat. ion; and, how the identified seismic problems involving.the Diablo Canyon containment building annulus areas
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[7590-01]
. were caused and subsequently discovered.
The results of this special inspection indicated, accng other things, that required quality controls were not imposed upon PG&E's safety-related, service type contractorr until late 1977 or earPr 1978; and, many of the work activities performed by PG&E with regard to the URS/Blume contract were performed in an informal manner.
On November 19, 1981, an order was issued by the Commission which suspended License No. DPR-76.
DPR-76 had been issued on September 22, 1981, and had authorized fuel loading and the conduct of tests at up to five percent of rated power at Diablo Canyon Unit 1.
This order, in conjunction with a letter from the NRC Office of Nuclear Reactor Regulation, defined what would be required from PG&E prior to start of fuel loading and prior to powe'r operation above five percent power at Diablo Canyon Unit 1.
These requirements included the completion of an independent design verification program for seismic-related service contracts.
In conjunction with this the licensee was directed to submit a detailed program plan for conducting the d' rig ~n verification and to s.upply information that demonstrates the independence of the companies proposed to conduct the independent verification.
The licensee has submitted a program plan and information regarding the independence of the contractor (R. L. Cloud) selected by the licensee.
Prior to an NRC decision on the acceptability of the program plan and the designated. independent contractor an additional issue, arose.
This issue involves the licensee's review and comment on draft editions of the independent consultant's repo'rt prior to the submittal of the report to the NRC, and statements made by licensee representatives to the NRC which led the NRC to believe that the licensee had not seen drafts of the report.
The issue was the subject of an NRC investigation.
Findings of this investigation, are contained in NUREGS 0862, Issues 2 and 3.
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[7590-01] Future reports on the acceptability of the program plan and the independent contractor will be made, as appropriate, in the Quarterly Report to Congress on Abnormal Occurrences (NUREG-0090 Series).
Dated at Washington, D.C. this day of 1982.
t Samuel J. Chilk Secretary of the Commission -
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