ML16341C343

Ack Receipt of Informing NRC of Action Taken to Satisfy Depth/Thickness Ratio Deficiency of Turbine Bldg Column Webs

ML16341C343
Person / Time
Site:	Diablo Canyon
Issue date:	12/21/1978
From:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:	Crane P PACIFIC GAS & ELECTRIC CO.
Shared Package
ML16341C344	List: ML16341C343 ML19263A765
References
NUDOCS 7901020286
Download: ML16341C343 (30)

Text

EQII 'Ip UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V SUITE 202, WALNUTCREEK PLAZA 1990 N. CALIFORNIA BOULEVARD WALNUTCREEK, CALIFORNIA 94599 DEC 21 579

-Docket Hos.

50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:

Nr. Philip A. Crane, Jr.

Assistant General Counsel Gentlemen:

Subject:

Modification Required to Satisfy the Depth/Thickness Ratio Deficiency for Turbine Building Column Ilebs, Diablo Canyon Units 1 and 2 (your letter of December ll, 1978)

Thank you for your letter referenced above which reported the action taken regarding the subject matter pursuant to 10 CFR 50.55(e).

Your report will be reviewed and evaluated and should we require addi-tional information concerning this matter, we will contact you.

Your cooperation with us is appreciated.

Sincerely, R.

H. Engelken Director 79010 20 2 gg

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(415) 781-4211 JOHN C. MORRISSGY TICE PRESIDENT AND GENERAL CDVNEEL MA) COLM H. PUROUSH A55QCIAIE OEOECAL CDOR5EL CHARLSS T, VAN OSUSSN PHILIP A, GRANS, JA, HCNAY 4, LOPLANTS AICHARO A. CLAAKS

-JOHN S. QISSON ARTHUR I, Hll LMAN,J R, ROSSRT OHLSACH C H AAL S 8 W. T H I S S S L I.

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H. Engelken, Director

'Office of Inspection and Enforcement Region V

U.S. Nuclear Regulatory Commission 1990 N. California Boulevard Walnut Creek Plaza, Suite 202 Walnut Creek, California 94596 Re:

Docket No. 50-275-OL Docket No. 50-323-OL Diablo Can on Site 27

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Dear Mr. Engelken:

On November 13,

1978, the NRC Office of Inspection and Enforcement, Regiori V, was notified by telephone of the following

~ situation which was deemed reportable under Paragraph (e) (ii) of 10 CFR 50.55.

Drawings of the Turbine Building showing modifications required by the Hosgri criteria were issued "Approved for Construc-tionTH A later review which required the consideration of a fully loaded crane coincident with the Hosgri event indicated that the

'more heavily loaded columns, which had no required modifications on the approved

drawings, had not been checked for depth/thickness ratios for the column webs.

These ratios were found to exceed t:he allowables of the American Institute of Steel Construction (AISC)

Manual of Steel Construction, 7th edition, Speci~ication for Plastic Design.

This report is a summary of the actions taken regarding this deficiency.

'I A Nonconformance Report (NCR), No. DCO-78-EG-018 was

'initiated November 13, 1978, in accordance with Procedure 9.1 of the PGM Engineering Manual.

Drawings showing the modifications required to satisfy the depth/thickness ratios of the AISC Specifi-cation were issued "Approved for Construction" on November 17, 1978.

The modifications consisted of welding to the web and flanges stiffener plates between the column flanges at appropriate spacings.

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Mr. R.

H. Engelken December ll, 1978 The personnel involved in the Hosgri analysis and design of the Turbine Building modifications have been instructed to pay particular attention to the provisions of Part 2, Plastic Design Methods, of the AISC Specification in order to prevent recurrence of a similar situation.

Therefore, in accordance with Procedure 9.1, resolution has been completed and corrective action taken.

V ry truly yo s,

PHILI A. CRAM, JR.

BEGULAT('~

INFORMATION DISTRIBUTION SYSTEM ACCESSI 901290267 DOC.DATF.: 78/12/19, NOT

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FACI:~0-275 ablo Canyon Nuclear Power Plant l, Pacif ic 50-Diablo Canyon Nuclear Power Plant-2,, Pacific AUTH.NAME AUTHOR AFFILIATION CRANE,P.A.

Pacific Gas 8, Electric Co.

RECIP.NAME RECIPIENT AFFILIATION STOLZ,J.F.

Light Water Reactors Branch 1

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'BR 22 AD SITE TECH 27 FFFL TRT SYS 29 KIBKllOOD AD PLANT 5YS AD SITE ANLYSIS MPA SUBJECT-Forwards info in response to requirements of SER Suppl 8 re piping mod,effect of contain~ent tilting on safety-related sys,equipment to be retested electricity, fault protective sys 8, fire protection sys.

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OOUOLASA OSLESOY J, MICHAELREIOENSACH IVOS C. RANSOM

~ UC ANN LEVIN OCNIVV JACKW ONUCK OHISLEY* WOO Mr. John F. Stolz, Chief Light Water Reactors Branch No.

1 Division of Project Management U.S. Nuclear Regulatory Commission Washington, D.C 20555

Dear Mr. Stolz:

Re:

Docket No. 50-275-OL Docket No. 50-323-OL Diablo Canyon Units 1 and 2

The following information is supplied in response to requirements in SER Supplement 8.

Cross Tie - Minor Pi in Modifications I%I PI 'II l Regarding Section 3.2.1:

PIIQQUi I'L II Piping for the transfer of water from the fire water tank to the auxiliary feedwater pump suction for extended hot shutdown operation is presently being designed.

Analysis has shown that the cross-connection will not impose excessive loads on the fire water piping, the auxiliary feedwater suction piping, or any pipe hangers, even in the event of the postulated Hosgri seismic acceleration.

The cross-connection will include two manual valves in parallel to insure operability in the event of a single failure of a valve to operate.

This cross-connection is mentioned on page 7-17 of the "Hosgri Report."

That description is being amended to include the provision for two parallel valves.

A schematic diagram of the cross-connection is attached to this letter (attachment 1).

Effects of Containment Tiltin on'afet -Related S stems Connected to onta'inment Regarding Section 3.9.3.4.4 PG6E has re-evaluated the piping supports on the pipin systems referenced.

Using conservative assumptions, the supports were evaluated for a combination of inertia plus tilting and found to be adequate.

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.?Ar. John F. Stolz December 19 1978 E ui ment to be Retested Electrical As ects Regarding Section 3.10.3:

Page 3.38, Item 5:

The results of tests to the main control board indi-cating instruments are discussed in paragraph 10.3.15.3.5 on page 10-69 of the Hosgri Evaluation Report.

The calibration of the indicating meters was checked before the test sequence began and after the test sequence was completed.

The calibration did not shift more than the required accuracy (2%).

Page 3.38, Item 6:

The results of tests to the hot shutdown panel indica-ting instruments are discussed in paragraph 10.3.9.2 on page 10-54 of the Hosgri Evaluation Report.

The calibration of the indicating meters was checked before the test sequence began and after the test sequence was completed.

The calibration did not'hift more than the required accuracy (2%).

Page 3.39, Item 12:

The results of tests to the valve limit switches are discussed in paragraph 10.3.30.4 on page 10-134 of the Hosgri Evalua-tion Report.

The valve function monitoring and recording described included the motor voltage and amperage, which demonstrated that the switch contacts did not chatter during the tests.

Redundant Position Indicati'onfor "L'ocke'd Out" Valves Regarding Section 7.6:

All valves listed in Table 6.3-10 are provided with redundant position indication in the.main control room..

Red and green indicating. lights are mounted next to each valve's control switch.

A white monitor light is also provided to specifically alert the operator of any off-normal valve position.

When valve lock-out removes control power, a separate power supply has bein provided for the red/green light indicators.

All lights are controlled by valve operator'osition switches and all power supplies are Class IE.

Fault Protective S stems for Co'n't'a'inm'ent Penetrations Regarding Section 8.1:

PG&E will fulfillthe requirements of the Staff's position (attachment

2) on overcurrent fault protective systems for containment penetrations.

.Mr. John F. Stolz

.cember 19, 1978 We have agreed to provide the 'primary protection re-quired by the Staff's position before fuel loading.

Independent back-up protection will be installed during the first refueling period.

Fire Protection S stem Regarding Section 9.6.1:

Certain fire protection items in Section 9'.1 of SER Supple'ment No.

8 were listed as outstanding and in need of further evaluation by NRC Staff or requiring confirmation that PG6E will meet certain commitments'he meeting of November 29, 1978 with PGBE and NRC Staff personnel clarified and, resolved these open items.

This letter provides a summary of the agreements reached in that meeting.

Five items listed as outstanding and in need of further evaluation by the Staff are described below:

1.

As required by the Staff, key fire system valves necessary to ensure fire water supply will be provided with electrical super-vision.

These key valves consist of the yard loop valves and the valves in the yard loop feeder lines to the plant.

Addi-tionally, valves in the supply line from the raw water reservoir will be locked open.

2

~

The required verification of alternate shutdown capability inde-pendent of the cable spreading room and control room has been furnished in our submittal of November 13, 1978 Demonstration that failure of newly installed nonseismic fire protection equipment will not prevent bringing the plant cold shutdown has been furnished in our submittal of November 13, 1978.

I 4.

Demonstration that all fire barrier cable penetration seals have three hour ratings has been furnished in our submittal of November 1978.

5.

Full scale fire testing in accordance with the ASTM E-119 Fire Test will be conducted to verify adequacy of fireproofing used to protect vital electrical cabling.

Preparations for the test-ing at the University of California are under way and the testing will be completed prior to plant operation.

We will advise the Staff of testing dates should they want to witness the test.

In addition to the fire items mentioned

above, twelve items required confirmation that PG6E would meet certain commitments.

These items were discussed at the meeting of November 29, 1978 and a summary of the agreements reached are as follows:

Mr. John F. Stol~)

cember 19, 1978 A halon 1301 fire protection system to protect the safeguards rooms and cabinets will be installed'in accordance with our commitment made in the November 13, 1978 submittal.

Based on the discussions with the Staff on November 29, PG&E now understands Staff requirements and will upgrade doors a.

between the auxiliary building supply fan room and the stairwell, b.

between Unit 1 fire zones 3-'P-2 and 31, c.

between Unit 2 fire zones 3-V-2 and 32, and d.

between the auxiliary building supply fan rooms and the out-side (upgraded to "C" label).

Other door modifications that have been made as a result of the fire protection review are summarized on the drawings showing fire zone door ratings (addenda C 'of the August 3,. 1978 submittal).

PG&E will install a Class IE alarm syst: em to annunciate loss of battery room ventilation "as specified in our November 13, 1978 submittal.

PG&E will construct two-hour rated fire barriers around one train of electrical cables for the diesel generator fuel transfer pumps in those fire zones in which a postulated fire could damage circuitry for both fuel transfer pumps.

Those fire zones are 3-J-1 (component cooling water pump room),

10 (12KV switchgeai room),

12-D, 12-F (corridors adjacent to 4KV cable spreading rooms),

and ll-D (corridor outside diesel generator rooms).

As a result of discussions with the Staff on November 29, 1978 it was determined that the area where barriers for electrical cabling should be constructed for the corridor adjacent to the 4KV cable spreading room (fire zone 12-D) and not 13-E as speci-field in the SER.

This commitment was made 'in our November 13, 1978 submittal, and we consider ourselves to be in compliance with Staff requirements on this issue.

In the November 13, 1978 submittal detailed information was pre-sented describing the diesel generator room drainage system.

During the discussions on November 29, 1978 the Staff concurred, with PG&E that the drainage system in the diesel generator rooms is sloped in such a manner that fire traps in the drainage system are not necessary.

In lieu of providing a two-hour rated ceiling for fire zone ll-D (diesel generator corridor),,PG&E intends to provide two-hour fire rated barriers to protect diesel generator and fuel transfer pump control circuitry in the area.

This alternate provides protection equivalent to a two-hour rated ceiling and satisfies the required commitment.

Mr. John F. Stolz De ember 19, 1978 8.

PG&E will meet the requirement for seismically qualified guard pipes around hydrogen piping in safety related'areas of the plant.

9.

PG&E will position newly installed transfer switches in the 480V switchgear so that a fire in fire zone 5-A-4 (hot shutdown panel area) cannot transfer control of both trains of safety-related equipment away from-the control room.

10.

PG&E will commit to providing two-hour rated fire barriers around electrical cables of one of the redundant trains of the auxiliary feedwater system in fire zone 3-BB, elevation 100 ft.

ll.

During discussions with the Staff and PG&E on November 29, 1978 it was agreed that considering the separation distance between redundant trains, appropriate protection for instrumentation cabling in fire zone 3-BB (penetration

area, elevation 100 ft.)

will be provided by the automatic sprinkler system to be installed in the area.

12.

The issue of electrical supervision" of the system valves was dis-cussed above.

During the course of discussions with the Staff on November 29, 1978 a number of detailed areas were discussed'n an attempt to preclude further misunderstandings.

These items and the understandings between PG&E and the Staff are summarized

below, On page 9-8 of SER Supplement No.

8, the areas in which automatic sprinkler systems are to be installed are listed. It was agreed that item (c) of that list could be deleted since the area of interest is more properly listed as item (g).

As a result of informa-tion provided in our November 13, 1978 submittal that verified adequate separation distance between redundant trains of electrical cabling inside containment, it,was agreed that item (e) could be deleted from the list of sprinkler<') areas.

This verification of adequate separa-tion distance also eliminates the need for two-hour barriers between redundant trains of electrical cabling inside containment.

For item (h), it was clarified that automatic sprinklers would be provided in fire zone 3-BB elevations 100 and 115 ft., but not elevation 85 ft.

This is in keeping with previous agreements and the commitment made in our July 7, 1978 submittal.

Details of fire protection modifications already com-pleted or in progress were discussed with the Staff in the, November 29 meeting.

In particular, laboratory area fire barrier modifications as committed in our submittal of August 3, 1978 were described and the Staff confirmed that these modifications are what is required for compliance with the requirements specified in SER Supplement No.

8.

~ In summary, with the exception'of the fire testing yet to be conducted that will confirm the adequacy of'ireproofing con-figurations, all outstanding fire protection issues have been resolved

Hr. John F, Stolz ecember 19, 1978 and all necessary commitments for fire protection modifications will be implemented in accordance with the schedule specified in SER Supplement No.

8.

Kindly acknowledge receipt of the above material on the enclosed copy of this letter and return it to me in the enclosed addressed envelope.

e truly you P ILI HE, JR.

Enclosures CC w/enc.:

Service List.

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ltCvJ CoNAQC AMQ

$v hoSeS I

Q FcY 434 pac437 For more FSAR For more FSAR For more FSAR details of piping connected to the reservoir, see Fig. 3.2-16 Sheet 3.

details of piping connected to the fire water tank, see Fig. 3.2-18 Sheet 2.

details of piping at the auxiliary feedwater

pumps, see Fig. 3.2-03 Sheet 2.

TTACH!P~J.1T 2

7.2 Containment Integrity:

Overcurrent fault protective systems for con-tainment p'enetrations.

Regulatory Guide 1.63, Revision 1

was classified as a Category II review item by the Regulatory Requirements Review Comoittee meeting No. 60, March 27, 1977, for all applications not evaluated under Revision 0 to. Regulatory Guide 1.63.

Pursuant with this Category II classification, the Diablo Canyon appli-cant was requested to describe how their penetration design meets Regulatory Guide 1.63, Revision 1.

'n this regard the applicant was requested to:

1)

Identify each type of electrical circuit that penetrates-con-tainment.')

Describe the primary and backup over current protective systems provided for each type of circuit identified in item l.

3)

Describe.the fault-current - versus-time for which the primary and backup over current protective systems are designed and qualified.

4)

Describe the fault-current-versus-time for which the penetratiom are designed and qualified.

5)

Provide coordinated curves between items 3 and 4 for each circuit identified in item 1 to show that the fault-current-ve'rsus-time condition to which the penetrations is qualified will not be exceeded.

6)

Describe the provisions. for periodic testing under simulated fault conditions.

In response to our request the applicant provided fault current-versus time curves for primary and backup overcurrent protective systems.

Thev also provided (informally as part of the qualifications for oenetratinns) fault-current-versus-time curves for which the penetrations are designed and qualified.

It appears from this information that protec-tive systems have not been designed to provide overcurrent fault protection for containment penetrations.

Therefore, to assure.con-tainment integrity given an electrical fault, we require compliance with the recommendations of Regulatory Guide 1.63 or an acceptable alternative, method and solution With bases.

In this regard, we,require that the protective systems for each type of circuit passing through containment (Class lE as well as non-Class lE circuits) must provide for independent primary and backup overcurrent fault protective devices to preclude a single failure from impairing containment integrity.

In addition, the protective systems must meet the following requirements of IEEE-279:

4.

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e A.

Each system shall, with precision and reliability, automatically disconnect circuits passing through containment when currents ex-ceed preset limits.

These preset limits must not exceed the limit for which the containment penetration has been designed and qualified.

B.

All primary anc'ackup breaker overload and short circuit protec-tion systems shall be qualified for the service environment as follows:

Class 1E S stems and Com onents l.

Should be environmentally qualified in accordance with the applicable standards and criteria.

C 2.

Should be seismically qualified to demonstrate that before, during and after a safe shutdown earthquake:

(1) closed breakers will remain closed (energized circuits will remain energized),

(2) open breakers will remain open (deenergized circuits will remain deenergized),

and (3) breakers which are required to be remotely operated

'opened or closed) are so operable.

Seismic qualification of breakers need not demonstrate actual fault current interruption capability during a seismic event.

<< ~ <<Ag 1<<

<< Non-Class 1E S stems ard Com onents l.

No formal environmental or seismic qualification is required.

However, the equipment should be of, high industrial quality which should be verifably by appropriate procurement documen-tation.

2.

The seismic capability should as a minimum assure that the systems remain operable, during an operating basis earthquake.

I C.

The circuit breaker protection system trip set points and breaker co-ordination between primary and backup protection shall have the capability for test and calibration.

Provisions for test under simulated fault conditions should be provided.

For designs where protection is provided by a combination of a breaker and a fuse or two fuses in series, provisions shall be provided for testing fuses.

D.

No single fai lure shall cause excessive currents.in the penetration conductors which will degrade the penetration seals.

E.

Where external control power is used for actuatinq the protective sys'tems, signals for tripping primary and backup system devices'shall be independent, physically separated, and powered from separate sources.

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