ML16342B788

Summary of 910618 Meeting W/Util in Rockville,Md Re Use of Results of long-term Seismic Program in Future Mods at Plant.Nrc Recommended That Licensee Include 230-volt Switchyard in Table 1

ML16342B788
Person / Time
Site:	Diablo Canyon
Issue date:	06/20/1991
From:	Rood H Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
TAC-55305, TAC-68049, NUDOCS 9107020467
Download: ML16342B788 (20)

Text

Docket Nos.

50-275 and 50-323 JUN 2 0 fs91 LICENSEE:

FACILITY:

SUBJECT:

Pacific Gas and Electric Company (PG&E)

Diablo Canyon Nuclear Power Plant, Units 1 and 2

SUMMARY

OF JUNE 18, 1991 MEETING HELD IN ROCKVILLE, MARYLAND TO DISCUSS USE OF THE RESULTS OF THE LONG-TERN SEISMIC PROGRAM IN FUTURE MODIFICATIONS AT DIABLO CANYON (TAC NOS.

55305 AND 68049)

On June 18, 1991, the NRC staff met with the Pacific Gas and Electric Company (PG&E) in Rockville, Maryland to discuss how PG&E will establish procedures to use the results of the Long-Term Seismic Program (LTSP) in future plant modifications.

Attendees at the meeting are listed in Enclosure 1.

At the meeting PG&E presented a flow diagram showing the method it plans to use to evaluate plant modifications against the LTSP results, in addition to evaluating them against the plant seismic qualification basis (defined as the design earthquake, the double-design earthquake, and the Hosgri reevaluation earthquake).

The proposed flow diagram is given in Enclosure 2.

Other material presented by PG&E at the meeting included a draft description of the scope of the LTSP check on future plant additions and modifications, and a

draft table (Table 1) defining the types of plant modifications that will be checked against LTSP spectra.

This material is given in Enclosure 3.

At the conclusion of the meeting, the NRC staff recommended that PG&E (1) include the 230-kV switchyard in Table 1, (2) define quantitatively what is meant by a "significant" reduction in high confidence of low probability of failure (HCLPF) as used in Enclosure 2,

and (3) define quantitatively what is meant by "HCLPF greater than demand" as used in Enclosure 2.

PG&E stated that it would revise the proposal to reflect the staff recommendations, and would submit it on the docket in about two weeks.

ORIGINAL'IGNED BY Harry Rood, Senior Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation p>07oaoo67 9i0620 PDR ADOC~ 0 PDR

Enclosures:

As stated

.DISTRI BUT ION NRC

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MVirgilio EJordan DRPW/PD5/PM DRPW/PD5/D~

HRood JDyer 06/g/91 06/g/91 Region V (4)

GBagchi RRothman RPichumani AHodgdon PSobel cc w/enclosures:

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Mr. J.

D. Shiffer Pacific Gas and Electric Company Diablo Canyon CC:

NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.

Box 369 Avila Beach, California 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California

.6715 Rocky Canyon Creston, California 93432 Ms. Sandra A. Silver Mothers for Peace 660 Granite Creek Road Santa Cruz, California 95065 Ms. Jacquelyn C. Wheeler 3303 Barranca Court San Luis Obispo, California 93401 Managing Editor The Count Tele ram Tribune 1321 Johnson Avenue P. 0.

Box 112 San Luis Obispo, California 93406 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Richard F. Locke, Esq.

Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California 94120 Mr. John Hickman Senior Health Physicist Environmental Radioactive Mgmt. Unit Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacramento, California 95814 Regional Adminstrator, Region V

U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Peter H.

Kaufman Deputy Attorney General State of California 110 West A Street, Suite 700 San Diego, California 92101 Ms. Nancy Culver 192 Luneta Street San Luis Obispo, California 93401 Michael M. Strumwasser, Esq.

Special Assistant Attorney General State of California Department of Justice 3580 Wi lshire Boulevard, Room 800 Los Angeles, California 90010

Pacific Gas and Electric Company 'Long Term Seismic Program Di ab 1 o Canyon CC:

Dr. Keiiti Aki Department of Geological Sciences University Park University of Southern California Los Angeles, California 90089-0741 Dr. Ralph J. Archuleta Department of Geological Sciences University of California Santa Barbara Santa Barbara, California 93106 Dr. Robert D. Brown, Jr.

U.S. Geological Survey Mail Stop 977 345 Middlefield Road Menlo Park, California 94025 Dr. David B. Slemmons 2905 Autumn Haze Lane Las Vegas, Nevada 89117 Dr. Robert Fitzpatrick Building 130 Brookhaven National Laboratory

Upton, New York 11973 Dr. C. J. Costantino Bui lding 129 Brookhaven National Laboratory

Upton, New York 11973 Dr. Michael Bohn Sandia Lab. - Organization 6412 Post Office Box 5800 Albuquerque, New Mexico 87185 Dr. James Johnson EQE 595 Market Str eet, 18th Floor San Francisco, California 94105 Dr. Steven M. Day Department of Geological Science San Diego State University San Diego, California 92182 Dr. Jean Savy Mail Code L-196 Lawrence Livermore National Laboratory P. 0.

Box 808 Livermore, California 94550 Dr. Anestis S. Veletsos 5211 Paisley Avenue

Houston, Texas 77096 Dr. Kenneth Campbell Dames and Moore 27728 Whirlaway Trail Evergreen, Colorado 80439 Dr. M. K. Ravindra EQE 3150 Bristol Street, Suite 350 Costa Mesa, California 92626 Dr. James Davis Division of Mines and Geology 660 Bercut Drive Sacramento, California 95814 Dr. Morris Reich Bui 1 ding 129 Brookhaven National Laboratory

Upton, New York 11973 (15)

ENCLOSURE 1

Attendees June 18, 1991 Meeting to discuss use of LTSP results in future plant modifications NAME R. C.~n erson G. Bagchi S. Bhattacharya A. Dummer J.

Dyer A. Hodgdon D. Ovadia R. Pichumani H.

Rood R.

Rothman J.

Tomkins ORGANIZATION NRC/NRR/DET/ESGB PGSE NRC/NRR/DRPW/PD5 NRC/NRR/DRPW/PD5 NRC/OGC PG&E NRC/NRR/DET/ESGB NRC/NRR/DRPW/PD5 NRC/NRR/DET/ESGB PG5E

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ENCLOSURE 2

Flow diagram presented by PG&E June 18, 1991 Meeting to discuss use of LTSP results in future plant modifications Design Change 10 CFR 50.59 review Does change impact items listed in Table 1?

No STOP Yes Evaluate effects of change on, seismic capacity specified in Tables 6-23 and 6-24 of LTSP Final Report Does change significantly reduce HCLPF No STOP Yes Redesign or modify Yes Is redesign or modification preferred?

No Develop revised plant HCLPF value No Is plant HCLP greater than delTland?

Yes STOP

ENCLOSURE 3

Draft Materi a 1 Presented by PG&E at June 18, 1991 Meeting to discuss use of LTSP results in future plant modifications

GRAFT DRAFT (June 18, 1991) ii n

ifi i

Future DCPP additions and modifications willbe designed and constructed in accordance with the existing Seismic Qualification Basis which includes earthquake motions as defined for DE (Design Earthquake),

DDE (Double Design Earthquake) and Hosgri applied with the attendant acceptance criteria and methodology defined in the license.

In addition, in order to take advantage of the insights and knowledge gained from the LTSP, certain specific future additions and modifications willbe checked against the LTSP spectra described in SSER 34 to verify that the plant highmnfidence-low-probabilitywf-failure (HCLPF) values remain acceptable overall, by assuring that the plant HCLPF capacity estimates resulting from each addition and modification are at least equal to the seismic demand (SSER para. 3.8.1,8, p. 342).

These specific additions and modifications are listed in Table l.

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1.

The LTSP findings have demonstrated that the use oforiginal plant design criteria and methodology for DE, DDE and Hosgri consistently produces an adequately conservative design.

2.

The future additions and/or modifications of the structures and components that will be checked against the LTSP Spectra ("Screened in" Structures and Components) are selected based on the following:

a.

Seismic Probabilistic Risk Assessment Studies have identified Structures and Components that have significant contribution to the plant seismic risk (e.g., turbine building, diesel control panel etc.).

Consistent with the results of these studies, it is determined the major contribution to seismic risk generally comes from those safety related components whose Spectral Acceleration Capacities (in terms of HCLPF) is less than 3g.

b. Major modifications to structures particularly important to plant safety are included (e.g. the containment and auxiliary buildings).

Major modifications are defined as those changes that significantly affect the dynamic properties (such as mass, stiffness) and strengths ofthe structures.

c. New/Unique Structures (such as II/IStructures) that significantly impact the seismic margins of the existing safety-related structures.

d. Masonry Walls (all new construction)

e. Specific issues resulting from the LTSP margins evaluation; relay chatter and electrical panel anchorage.

f. New major safety related equipment whose spectral acceleration capacities were not previously reported and which significantly impact seismic margins.

(e.g., Sixth diesel generator).

3.

Some additions and modifications to the structures, equipment and components need not be checked ORav-

0

DRAFT DRM~

against the LTSP Spectra.

These modifications will be designed in accordance with he existing (June,18 19%1>

Seismic Qualifications Basis (which includes original design basis, DE, DDE and Hosgri evaluation basis).

These modifications include the following:

a.

Seismically like-for-like replacement of structures, equipment and components.

These replacements willnot change plant seismic margin.

b.

Minor additions or modification to structures (such as, access platform, typical core drills, modifications to non-structural elements, etc.). These additions and modifications willnot significantly affect plant HCLPF.

c.

Additions or modifications to electrical raceways and supports.

These commodities have high seismic margins due to redundancies in design and high damping.

d.

Additions or modifications to HVACDucts and ducts supports.

These commodities have high seismic margins due to redundancies in design.

(However new dampers with "fusable links" willbe checked against LTSP).

e.

Additions or modifications to Piping and Supports as they have high seismic margins and ample design redundancies.

f.

Additions or modifications to hand operated valves, relief valves, solenoid valves and check valves dues to their high seismic ruggedness.

Airand motor operated valves are also included in this category.

Specific exceptions are noted in Table 1.

wp'eeismicdesgn 6/14/91 DRAFT

L

DRAFT (June 18, 1991)

Table I: List Of Phnt Modifications To Be Checked Against LTSP Spectra Future modifications or additions to the following structures and equipment willbe checked against the LTSP Spectra as described in the SSER 34 and as described in the "Description of Scope" above, to verify that the Seismic margins (as defined by HCLPF) for the plant remain acceptable overall, by assuring that the plant HCLPF capacity estimates for each addition and modification are at least equal to the seismic demand (SSER para. 3.8.1.8, p. 342).

PLANT SIRUCIUIUS

~ Major Structural modifications to (Note 1)

Containment building Concrete internal structure ~i

Auxiliarybuilding Turbine building Intake structure

~ New Category I Structures that significantly impact seismic margins

~ New major non~tegory I Structures that significantly impact seismic margins and that are located in the proximity of Category I Structures

~ Masonry Walls (all new construction)

EQUIPMENT AND COMPONENTS

~ Nuclear Steam Supply System Steam Generators Power Operated Relief Valve Reactor Coolant Pumps

~ Component Cooling Water CCW Heat Exchangers CCW Surge Tanks

~ Diesel Generator D.G. Excitation Cubicle

e k

D.G. Control Panel

~ Containment Fan Cooler

~ 4160 (vital) Electric Power ORAFl DRAFT (June 18, 1991)

Switchgear

~ 125v DC Electric Power Batteries Battery chargers Switchgear breaker panels

~

120v AC Electric Power Inverters

~ 480v (vital) Electric Power 4160/480v Transformers

~ Control Room Main control board (anchorage)

~ Miscellaneous Impulse Lines Relay (review for chatter potential)

New major safety related equipment whose seismic capacities were not previously reported and which significantly impact seismic margins.

Notes:

1. 'Ihe major modifications include those changes that significantly affect the dynamic properties (such as mass, stiffness) and strengths of the structures.

wpbeismicdesgn 6/14/91 GRAFT

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