ML16342B051

Responds to Request for Written Rept After Cancellation of ACRS 790331 Meeting Re Possibility of Problem W/Instrument Guide Tubes.Staff Rept Encl

ML16342B051
Person / Time
Site:	Diablo Canyon, North Anna
Issue date:	03/30/1979
From:	Crocker L Office of Nuclear Reactor Regulation
To:	Fraley R Advisory Committee on Reactor Safeguards
References
NUDOCS 7905100325
Download: ML16342B051 (18)

Text

Docket Nos. 50-338, 50-275.

and 60-323 MAR ~0 ]g7g Distributio Docket File NRC PDR Local PDR LWR 1 File LWR 3 File B. Buckley A. Dromerick E. Hylton M. Rushbrook E. Sullivan W.

Reinmuth Mr. Raylwnd F. Fraley Executive Director Advisory Committee on Reactor Safeguards U. S. Nuclear Regulatory Commission Washington, D.

C.

20555

SUBJECT:

INSTRUMENT GUIDE TUBES AT NORTH ANNA 1 AND DIABLO CANYON A discussion was scheduled at the flarch 1979 ACRS meeting regarding the possibility of a concern with the instrument guide tubes.at, Diablo Canyon similar to that found at North Anna 1.

The scheduled discussion was cancelled and the Committee suggested a written report instead.

The staff's report on this subject is provided in the enclosed note from E. Sullivan, Jr. to D. Allison, dated March 19, 1979,

~>hich summarizes the oral presentation that the staff intended to give to the Committee.

With regard to other plants, the Office of Inspection and Enforcement is,considering issuing a circular on this subject.

Sincerely, Enclosure; Note to D. Allison from E. Sullivan, Jr.

dated March 19, 1979 cc:

See page 2

Lawrence P. Crocker, Technical Assistant Division of Project t7!anagement IIt

-'ffice of Nuclear Reactor Regulation 7g(/L (6C/92$

L'WR BBuckley/red

,3/2P/,79...,

OPPICC3P.

0VRNAMC~

DAT23P Form hEC-318 (R07. 9.$ 3) hZCM 0240 LWR+

JStofz 3/g/7,9,,

,. DSS,...,

ESUlli.

n 03/~g/79 Ll Dl'II+/

DBVas allo LPCrocker

. ei rirgu.ih

.3INI.?.9.......,...,.3 Jy~ll79 03/Za

/79 6 U, 0. COYCRNMRNT PRINTINO OPPICKI 1074 020 100

4 0

~a g~%ks S

\\ t K

4 1

1

\\

w

\\

y r

C I

l

'd IL I ~

II

Hr. John C. Mori ey MAR 3 0 1979 Mr. John C. Morrissey Vice President 8 General Counsel Pacific Gas 8 Electric Company 77 Beale Street San Francisco, California 94106 CC:

Philip A. Crane, Jr.,

Esq.

Pacific Gas

& Electric Company 77 Beale Street San Francisco, California 94106 Hr. Richard Hubbard HHB Technical Associates 366 California Avenue Palo Alto, California 94306 Janice E. Kerr, Esq.'alifornia Public Utilities Commission 350 HcAllister Street San Francisco, Californ'ia 94102 Mr. Frederick Eissler, President Sceni c Shorel i ne P reser vat ion Conference, Inc.

4623 More Mesa Drive Santa Barbara, California 93105 Ms. Elizabeth E. Apfelberg 1415 Cazadero San Luis Obispo, California 93401 Ms. Sandra A. Silver 1792 Conejo Avenue San Luis Obispo, California 93401 Mr. Gordon A. Silver 1792 Conejo Avenue San Luis Obispo, California 93401 Paul C. Valentine, Esq.

321 Lytton Avenue Palo Alto, California 94302 Yale I. Jones, Esq.

19th Floor 100 Van Ness Avenue San Francisco, California 94102 Hr. John Marrs Managing Editor San Luis Obispo County Telegram - Tribune 1321 Johnson Avenue P. 0. Box 112 San Luis Obispo, California 93406 Elizabeth S.

Bowers, Esq.,

Chairman Atomic Safety 8 Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.

20555 Mr. Gl enn 0. Bright Atomic Safety 8 Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.

20555 Tolbert Young P. 0.

Box 219 Avila Beach, California 93424 Richard S. Salzman, Esq.,

Chairman Atomic Safety

& Licensing Appeal Board U. S. Nuclear Regulatory Commission Washington, D. C.

20555.

Dr. W. Reed Johnson Atomic Safety

& Licensing Appeal Board U. S. Nuclear Regulatory Commission Washington, D. C..

20555 Alan S. Rosenthal, Esq.

Atomic Safety

& Licensing Appeal Board U. S. Nuclear Regulatory Commission, Washington, D. C.

20555

0

A Mr. John C. Morrsssey MAR 80

>g7g cc:

Ms. Raye Fleming 1746 Chorro Street San Luis Obispo, California 93401 Brent Rushforth, Esq.

Center for Law in the Public Interest 10203 Santa Monica Boulevard Los Angeles, California 90067 Arthur C. Gehr, Esq.

Snell 8 Wilmer 3100 Valley Center

Phoenix, Arizona 85073 Mr. James

0. Schuyler, Project Engineer Pacific Gas 8 Electric Company 77 Beale Street San Francisco, California 94106 Bruce Norton, Esq.

3216 North 3rd Street Suite 202

Phoenix, Arizona 85012 Mr.

W.

C. Gangloff Westinghouse Electric Corporation P. 0.

Box 355 Pittsburgh, Pennsylvania 15230 Michael R. Klein, Esq.

Wilmer, Cutler 8 Pickering 1666 K Street, N.

W.

Washington, D. C.

20006 David F. Fleischaker, Esq.

1025 15th Street, N.

W.

5th Floor Washington, 0. C.

20005 Or. William E. Martin Senior Ecologist Battelle Memorial Institute

Columbus, Ohio 43201

~

~

" Mr. W. L. Proffitt Senior Vice President

- Power Operations Virginia Electric 8 Power Company P. 0.

Box 26666 Richmond, Virginia 23261 MAR 3 0 1979 CC:

Mrs. James C. Arnold P. 0. 'Box 3951 Charlottesville, Virginia 22903 Mr. Anthony.Gambaradella Office of the Attorney General ll South 12th Street Room 308 Richmond, Virginia 23219 Richard H. Foster, Esq..

211 Stribling Avenue Charlottesville, Virginia 22903 Michael W. Maupin, Esq.

Kunton, Williams, Gay 8 Gibson P. 0.

Box 1535 Richmond, Virginia 23212 Mrs. June Allen 412 Owens Drive Huntsville, Alabama 35801 Mr. James Torson

,501 Leroy

Socorro, New Mexico 87801 Mrs. Margaret Dietrich Route 2,

Box 568 Gordonsville, Virginia 22942 William H. Rodgers, Jr.,

Esq.

Georgetown University Law Center 600 New Jersey

Avenue, N.W.

Washington, D. C.

20001 Mr. Peter S.

Hepp Executive Vice President "Sun Shipping 8 Dry Dock Company P. 0.

Box 540

Chester, Pennsylvania 19013 Mr. R. B. Briggs Associate Director 110 Evans Lane Oak Ridge, Tennessee 37830 John J.

Runzer, Esq.

Pepper, Hamilton 5 Scheetz 123 South Broad Street Philadelphia, Pennsylvania 19 109 Clarence T. Ki pps, Jr.,

Esq.

1700 Pennsylvania Avenue,.

N.W.

Washington, D.

C.

20006 Carroll J.

Savage, Esq.

1700 Pennsylvania

Avenue, N.

W.

Washington, D.

C.

20006 Mr. James C. Dunstan State Corporation Commission Commonwealth of Virginia Blandon Building Richmond, Virginia 23209 Alan S. Rosenthal, Esq.

Atomic Safety and Licensing Appeal Board U.S. Nuclear Regulatory Commission Washington, D. C.

20555 Michael C. Farrar, Esq.

Atomic Safety and Licensing Appeal Board U.S. Nuclear Regulatory Commission Washington, D. C.

20555 Dr. John H. Buck Atomic Safety'nd Licensing Appeal Board U.S. Nuclear Regulatory Commiss'ion Washington, D.

C.

20555 Atomic Safety and Licensing Board Panel U.S. Nuclear Regulatory Commission Washington, D. C.

20555

Mr.

W. L. Proffitt MAR 80 87g CC:

Mr. Michael S. Kidd U, S, Nuclear Regulatory Comnission P. 0.

Box 128 Spotslvania, Virginia 22553 Dr. Paul W. Purdom Department of Civil Engineering 0 rexel Uni vers ity Phi ladel phia, Pennsylvania 19104 Dr. Lawrence R. /varies Apartment No.

51 Kendal-at-Longwood Kennett Square, Pennsylvania 19348

gg,it ilKQIr

.a 'P

~ a 41

/y

+>>*++

UNIT E0 STATES t

NUCLEAR REGULATORY COMMIS WASHINGTON, D. C. 20555 tliAR 3

9 l)79 NOTE TO:

FROM:

SUBJECT:

D. Allison, Light Water Reactors Branch 81, DPW E. Sullivan Jr., Technical Assistant for Engineering, DSS INSTRUMENT GUIDE TUBES AT NORTH ANNA 1

AND DIABLO CANYON A licensee event report for North Anna 1

was submitted in November of 1978.

This report followed earlier notifications of a potential problem.'n

summary, a field modification had been made to the lower head insulation resulting in it being supported on the instrument guide tubes.

The supporting arrangement is that the insulation is vertically resting on angles that are clamped in a gridwork to 20 of the 53 tubes.

The loading on the guide tubes, due to the insulation, had not been considered in the original analyses of the tubing.

When the 'ana1yses was performed using the FSAR criteria, the licensee reported that the ASNE Code allowable stress and the yield stress for the OBE condition were exceeded for about ten tubes although the SSE allowable stress was not exceeded anywhere.

The maximum stress occurs in the socket welds between the guide tubes and the nozzles that penetrate the vessel.

The maximum stress was about 70Ã of the ultimate and, therefore, violation of the pressure boundary would not be expected.

VEPCO plans to modify the supporting arrangement by building a frame-work underneath the insulation, which will take the loading off the guide tubes.

This modification is planned for the first refueling outage in September 1979.

At Diablo Canyon the insulation is not supported from the guide tubes.

The insulation consists of sections covering the entire vessel.

The sections are bolted together.

As shown in Figure 1, the insulation fits close against the vessel and is hung from the eight coolant loop nozzles.

The bottom head sections have holes with clearances between the insula-tion and the nozzles,that the guide tubes are welded to.

The clearances are packed with fiberglass.

This is shown in greater detail in Figure 2.

We expect that there might be some contact between the insulation and the nozzles during an earthquake but only minor loading would be experienced and the nozzle stresses would be very low.

D. Allison O.

There was no specific analysis of the strength of the insulation itself for Diablo Canyon.

Westinghouse has compared the Diablo Canyon insulation design to the insulation on more recent plants that have been analyzed.

On the basis of this comparison of design and the analyzed "g" level, Westinghouse concluded that the insulation is qualified for the Hosgri event.

Therefore, we expect the integrity of'he insulation to be maintained during an earthquake.

The guide tubes for Diablo Canyon were reanalyzed for the Hosgri event and had previously been analyzed for the OBE.

The results indicated stresses, within the Code allowables.

E. Sullivan Jr., Technical Assistant for Engineering Division of Systems Safety

t la

J ~

V g,= 7- [/o" DIABLO CANYON.- REACTOR VESSEL LOlJER HEAD INSULATION I

)

I I

I I

~MD 'fO FUCK w<~'s ~esa.gas~

~~ Scc YK~ bt VTZCi I

b4) SpS~'F

~ aalu iaaeuW a-zo).-

I gg I

~ OET.

1

~

~

FIGURE 1

1

'o ma

'v E 5 S E. 4

. wA,CQ r ~

i I

~

r

>=<gprt r'r~

J r

r

~

r

~

't Ij r

r

/

I 4

r r

~ i

~

~

I I

r

.r

~ 8-

+l~ i/<

ST 5T'a 5Cl'RW 2H cjoy. ST.SYG. HovKBC'I WAS HQ R.

DIABLO CANYON-DETAIL OF GUIDE TUBE NOZZLE AND INSULATION etz FIGURE 2

~4 3