ML17083A990

Forwards Annotated Draft Commission Paper Requesting Approval of AO Determination Re Seismic Design Errors

ML17083A990
Person / Time
Site:	Diablo Canyon
Issue date:	02/16/1982
From:	Michelson C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML17083A991	List: ML17083A990 ML17083A992 ML17083A993
References
NUDOCS 8203040027
Download: ML17083A990 (18)

Text

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FEB 16 198 SAN l /,(

DISTRIBUTION Docket w origina'1 incoming)

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OELD HEMORANDUll FOR:

Carlyle Hichelson. Director DEsienhut/RPurple Office for Analysis and Evaluation of Operational Data FHi rag 1 ia JLee FROM:

Harold R. Denton, Director HSchierling Office of Nuclear Reactor ReguIation BBuckley RTedesco/LBerry

SUBJECT:

PROPOSED ABNORMAL OCCURRENCE - SEISMIC DESIGN ERRORS AT DIABLO CANYON NUCLEAR POllER PLANT

Ihis is.. in response to pour February 6, 1982 memorandum on the subject matter.

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'he writeup. enclosed in your memorandum appears to be factually correct.

However, it may require updating to reflect the current status of the Region V'investigation which is briefly mentioned on pages 6 and 6.

Enclosed is an annotated copy of the writeup which contains some additional comments for your consideration.

Enclosure:

As stated QrlgftlNISF+4 5

g. P. 08ntOn Harold R. Denton, Director Office of Nuclear Reactor Regulation SCavanaugh (w/ticket 882-057)

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NRC FORM 318 (10-80) NRCM 0240 OFFIC(AL RECORD COPY USQPO: 1981~960

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For:

From:

The Commissioners William J. Dircks Executive Director for Operations

Subject:

ABNORMAL OCCURRENCE RECOMMENDATION - SEISMIC DESIGN ERRORS AT DIABLO CANYON NUCLEAR POWER PLANT

Purpose:

Discussion:

Approval of an abnormal occurrence determination.

Enclosed is a draft Federal Register notice in regard to the 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 design, construction, use of, or management controls for licensed facilities or material I

can be considered an abnormal occurrence.

CONTACT:

0. Crooks/P.

Bobe 492-4425/492-4426

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Recommendation:

That the Commission:

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Approve the subject proposed abnormal 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.

Scheduling:

While no specific circumstances require Commission Action 4

by a particular date, it is desirable to disseminate 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.

Enclosure:

Draft Federal Register Notice William J. Dircks Executive Director for Operations

1

[7590-013 NUCLEAR REGULATORY COHMISSIOH ABNORHAL OCCURRENCE SEISMIC DESIGN 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 abnormal 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 abnormal occurrence using the criteria published in the Federal Register on February 2A, 1977 (42 FR 10950).

One of the general criteria notes that major deficiencies in design, construction, use of, or management controls for licensed facilities or material can be considered an abnormal occurrence..

The following description of the incident. also contains the

~b~ZZ,i~pi, ~ad av5.ii~el Date and PTace -

On September 28, 1981'nd September 30, 1981, Pacific Gas h

and Electric (PGAE) submitted letters to the NRC stating. that certain drawings

("diagrams")

used in the seismic design in the Diablo Canyon t

Unit 1 containment annulus ar'ea 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 additional design errors.

This resulted in suspension of the Diablo o~ hk venbew l9,I95I Canyon Unit 1 fuel load and low-power operating license.

(Unit 2 was still under construction and had not yet received an operating license).

Diablo Canyon Units 1 and 2 utilize pressurized water reactors and are

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located in San Luis Obispo County,.Mli.fornia.

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I L759O-Olj Nature and Probable Consequences On September 21,

1981, an engineer employed by PGKE in the hanger design

group, was performing work for Diablo Canyon Unit 2 in response to NRC IE Bulletin NO. 79-14 ("Seismic I

Analysis for As-Built Safety-Related Piping Systems" ).

This work involved the use of "diagrams" of the containment building annulus area.

The engineer became suspicious that the supposed Unit 2 "diagrams" h

did not accurately represent Unit 2 s'tructural 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 PGRE management were notified and they in turn contacted their seismic design.contractor,;

URS/John A.

Blume and Associates (URS/Blume).

V URS/Blume confirmed that the'rong "diagrams" had been used.

On September 26, PG8E management continued to evaluate the problem.

On September 27, the Plant Superintendent notified the NRC Senior Resident Inspector that a problem did indeed exist.

NRC investigation into the situation disclosed the following:

I'1)

The "diagrams" were developed at PGFiE and apparently given to URS/Blume on March 8,.1977 for their use in the development 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 wer4'ot aware that the Unit 1 and Unit 2 con-tainment annulus areas are mirror imaoes.

Therefore, during the

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L 7 590-01 j development of the associated seismic response

spectra, URS/Blume assumed that both Unit 1 and Unit 2 containment buildings were of the same configuration.

(3)

PG&E, upon receipt of the seismic response spectra in Nay 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.

PGSE, in turn, performed subsequent design calculations for Unit 2 and, 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 develop ent o ~f r4 Q

~peru)P of Unit 1 design requirements, PGEE~

Cod. ~rnpoeofCN 'n hie, conhainmatk Mhutu5 using the appropriate containment annulus frame orientation "diagrams".

and.

~ann(gyes 'indicate<

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that, as a result of the error, modifications were required to

~ gp bar ~k be made on 8+ Unit 1 pipe suppor'ts.

~ These modifications involved such actions as adding snubbers, changing the snubber size, adding braces, replacing structural

members, and stiffening base plates.

Subsequent investigations by the

NRC, and design reviews by PGEE and their consultant have identified a significant number of additional r

design concerns.

These include:

failure'o use the latest revision of the Pl

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vertical response spectra in design.of conduit and cable tray supports; Op incorrect weight distribution used'o determine the containment annulus l

vertical seismic response spectral curves; erroneous spectra used to

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[7590-01] complete 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 PGSE and transmitted to URS/Blume and the lack of independent review of these data within PGSE prior to submittal to URS/Blume.

Identification of the additional design errors indicates a more general failing in the licensee's design quality controls 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 if 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.

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HRC - In October 1981, the HRC conducted a special inspection, at the PGSE URS/Blume offices in San Francisco, California to evaluate the quality assurance programs and other management control systems in effect at PGEE and at URS/Blume during the period from 1970 to present; the extent

'I 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 informatidh; and, how the identified seismic 7

problems involving the Diablo Canyon containment building annulus areas

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were caused and subsequently discovered.

The results of this special inspection indicated, among other things, that required quality controls were not imposed upon PGGE's safety-related, service type contractors uritil late 1977 or early 1978; and, many of the work activities perforiied by PGGE 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'2,

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'etter from the NRC Office of Nuclear Reactor Regulation, defined what would be required from PG8E prior to start of fuel loading and prior to power operation. above five percent power at Diablo.Canyon Unit 1.

These requirements 'included the completion of an independent desion verification program for seismic related service contracts.

In conjunction with this the licensee was directed to submit a detailed program plan for conducting the design verification and to supply information that demonstrates the independence of the companies proposed to conduct the independent verfication.

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 consul tant '

report 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

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the report.

The issue..

NRC investigation. Recting5 Q 6'i e (nvc5bi ~aQon al-c, ~nhvincJ f~ hlogs50 cc4z, ~uco 2and~5.

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[7590-01]

Future reports on acceptability of the program.plan and the independent contractor will be made, as appropriate, in..the Ouarterly Report to Congress on Abnormal Occurrences (NUREG-0090 Series).

Da.ed at Hashington, D.C. this day of 1982.

Samuel J..Chilk Secretary of the Commission

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