ML16341C320
| ML16341C320 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 04/26/1985 |
| From: | Pomeroy P Advisory Committee on Reactor Safeguards, RONDOUT ASSOCIATES, INC. |
| To: | Okrent D, Savio R, Seiss C Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML16341A656 | List: |
| References | |
| ACRS-CT-1810, NUDOCS 8506070052 | |
| Download: ML16341C320 (14) | |
Text
RONDCIUT ASCOClaTESe INCORPIOATED P.O. Box 224, Stone Ridge, New York 124SN 26 April 1985 Dr. Chester Seiss Dr. David Okrent Advisory Committee on Reactor Safeguards U.S.
Nuclear Regulatory Comnission Washington, DC 20555 Attn:
Mr. Richard Savio Dear Drs. Seiss and Okrent:
In response to a request from Mr. Savio, the purpose of this letter is to convey my coments on the discussions held at the 21-22 March 1985 meeting of the combined ACRS Subcommittee on Extreme External Phenomena and Diablo Canyon.
1.
Seismic Msargins In view of the ACRS concerns for this issue over the past eight years or so, the program for quantification of seismic margins is long overdue.
The Expert Panel on guantification of Seismic Design Margins has formulated an excellent program for the NRC Seismic Design Slargins Group.
The ACRS, ~throu h
S i<<,
ld i<< i ~~11 6
results and insure that the ~ro ram remains on-schedule for its three-Sear 2.
Diablo Canyon The Long Term Seismic Program Plan presented by PG and E
is an extremely comprehensive study of California tectonics.
There are particular points of concern, however, that should be considered.
1.
Geology--The very comprehensive nature of the proposed study may, in
- fact, result in a diffuse product.
The geol~a
~ro ram should be more
~shar 1
focused on the Diablo
~Can on issues.
In addition to the ESA
- input, a
broad representation of the obviously diverse geographical viewpoints should serve as input to this study and to the evaluation of data.
2.
Seismology--The seismology program is also not clearly focused.
The Seismology element should be the strongest part of this program, yet it is unclear exactly what will be done by whom.
The TERA expertise should be supple-".:.ted with consultants with particular expertise in this area.
PDR 0052 85051/ ---=-
000007 O
~DOCK OSO00arS PDR
Dr. Seiss and Okrent 26 April 1985 Page 2
3.
Technical Advisory Groups--Members of the Technical Advisory Groups are individually and collectively outstanding.
If these individuals had a deep, ongoing, day-to-day relationship to the
- Program, the concerns expressed in paragraphs I and 2 above would be lessened.
Because of the time commitments of these individuals, one suspects that the individual groups may meet on the order of one day/month and provide overview and guidance at a level commensurate with that participation.
PG and E
should consider a'greater level of participation by these and other con-sultants focused on the particular problems.
Thank you for the opportunity to participate.
I look forward to hearing the results of these programs as they evolve.
Sincerely yours, p~g LAP. A)Vr S/l ~J, (.QQ-)
Paul W.
Pomeroy PWP:gla
JOHN C. MAXWELL OEOLOQIST 5322 WESTERN HILLS DRIVE AUSTIN'EXAS 7B73I April 20, 1985 Yr. Richard Savio Advisory Committee on Reactor Safeguards H St.
U. S. Nuclear Regulatory Commission Washington, D.
C.
20555
Dear 'Y>r. Savio:
Subject:
Diablo Canyon Subcommittee Meeting Los Angeles, California March 21, 1985 Yy comments will address the P.
G. and E. Long Term Seis-mic Program Plan, dated
- January, 1985, which was discussed before the Subcommittee in Los Angeles.
I found the pre-liminary statement by the NRC staff to be very helpful in focussing on the primary elements of concern.
The program plan itself, as presented by the P.
G. and E. staff, is well thought-out and comprehensive.
Exper-ienced consultants have been engaged to advise them on the various tasks to be carried out. It did seem to me, however, that the program is too general and perhaps should be focus-sed more directly on the potential seismicity at the plant site.
The appointment of Yir. Lloyd Cluff by P.
G.
and E..
to be Manager of Geosciences and Yianager of the Long Term Seismic Plan investigation is very encouraging.
His years of experience with Woodward-Clyde and his reputation for integrity indicate that the required geological and geophysi-cal work will be carried forward expeditiously and carefully.
It is also comforting to know that the staff will have the advice of D. B. Slemmons and Robert Brown as this program evolves.
Cordially yours,
) A'hap
TRIP REFORT
=:I-'". MARi"H I'i'EETING ACR.=:
=:LIBCOMMITTEE itN EXTREME EXTERNAL F'HENOMENA AND DIABLO CANYON LOS ANC'LES~
CA R. J.
~cavv-=o Ph.D.~P.E.
~:ug -omm> t tee Meet >r>s i March
'1--"-'>1.'i~
1.
INTRODUCTI C>N
'I Two ma.ior to~ic ar.eas were discussed at the ACR~~
sub=ommi ate meetir>e.'1)
NRC Seismic Mar air>s F'r osram (SMF')
(2)
Lor>e Term.:eismi
= F'roeram (LT"P) of the Diablo Car>>or>
F'ower F'1 arit (DCF'F')
F'r eseritatioris were made tv the NRC Staf f i Corisul tants to the fi1RC:>
F'C~..!E '='ta f f >
ar> 5 i:ori
>J 1 tarit s to F'O'GE.
Listed t el ow are some of mv
=omments relevarit to these two topic al" eas
~
':". 1 ELECTR ICAL RELAY" Ther e i s
=or>cerr> about the res> onse and oper atiori of ele=tr i =al r ela>s dur ir>e a seismi
= event.
A frazilits test pr'osr'am i s pl armed.
Thl 5 test pr'09l am 15 ver'Y impor tant to insur e pl arit safety.
The L~'=: Mavv r esporise of
= ir:u ele=tr i:al envied m
r e:omnierided that the ir eva1 uat x ori pl arits.
has 5evel oped si~r>i fi=ant e "t crier>ce on the i t br eaker s an 5 the behavior of other.
crit to high impa t sho k
1 oads. It is the t)R'. '='taf f make use of this e <per ieri e iri of el e=tr.i =al
=omporierits for riu=1 ear power
- .2 CA."::TIBRITTLE MATERIAL Mater.ial s with 1 ow ducti litx resporid poor lx to dynamic loads.
Speci fi=al 1 v>
>3rav arid White Cast Iror>s~ Cast Alumir>ums i Fl tier C'lass Er o'<v Compos i tes arid Lel ami cs hi stor ical 1 v have failed wher> subjected to vibration or shock loads.
This statemerit does not mean that everz comporierit with a part fabr icated from one of these material s wil 1 fail.
However fai 1 ure of orie of these
=omr onerits is much more likely thar> those fabr icated from du=tile materials.
For eÃampl e
> the oril v failure iri a fossi 1 e fuel power plant (riot seismi =al 1 >
desirer>ed) that I kriow of occur ed iri a
=ast iron pipe fittir>e or f1ar>ee. It shoul 5 be emphasi=.ed that the tvpe of cast ir on used for this f ittir>s> (eras du =tile
> etc.
) is riot kriowri.
As a resvl t> it is recommended that a
surveys tie made of the mater ials used in safety related items of riuclear power plants arid that sf e=ial
=onsideration be riven to the fraeilitv of these items fabri=ated from brittle materials usine both test and analysis.
J
ACR'=.:=.ub:ommi t tee Meetirie i March "1-"i198
=:.;
ANCHf fR:=
Fai lures of esviPmerit from ear thevahe e::citation have ofteri o::ur e5 from bol t or ari:hor failur es.
Furthemorei e~uiPmerit is often an:hore5 into cori=r etc.
As a resul ti fraeilitv of anchors of safety related eeviPmerit must te thf'ouphl < eval vated
~
='.4 E'f fLT.'=:
It was merit ioried iri the Pr esentatiori (t v Dr.
R. f:eririedv) that bol t ziel dirie is sometimes considered in ioint arialvses.
Fvr ther frior e i i t is vrider stoo5 that high str er<<th bol ts are sorfietirlies used to arichor maior comPorierits to the colitainment structure.
It is strorie 1 v recommended that arichor bol ts be desi9ned for. ma;<imum crier ~v absor tion bv cutting the shanl: diameter to the root diameter of the bolt if this desierf feature is not already being emf loved. If this lfiodification is riot done and i f the bol t is 1 oaded be>'ond the riel d Poirit i Plastic strairis coriceritrate at the first few threads of 'he bol t. In 9eneral i
the str'or>92r'he bo 1 t the 1 ess the f 1 asti c str ain before fra:tvre.
The fatigue imr a=t strerieth of bol ts cari be ifi:reased t v a fa:tor of two to four (or mor e) bv cuttin'i the bol t sharil;. to the root diameter
. (Ref.
Har.r is 5 Crede
"""HOCH AND VIE'RATIffN HAf4DE'ffO),""<<:':rid Edi tiorii McC'raw Hi 1 1 iP 4"-8).
Thus i thi s s imP1 e mo 5i fi:at iori:an iri:rease the mar kiri of safety for dvriami c 1 oads s i eris f i =arit1 v arid i ther e fore i should be considered in both the
'=MP arid the LT".P of DCPP.
".5 =:OIL-STRfff'TURE INTERACTION The LT.":F'f'oPosed bv P65E is to te commerided of its throvehriess.
A few suggestion are offered related to the soi 1-str vctvr e interaction f rot lcm.
(1)F'r o~r am The Pf'oPosed Pl 0'9f'am Pl ovl des a urii9ve OPPorturii tv tp fur ther vri 5er starid soil str u=tvre iriter actiori and the tau effect for a stiff soil (soft rock) site (Vs about 486&fPs).
(:':)Fr.ee Field f rovrid moti,on Three tr ia:axial a=eel er ometers at di fferent 1 ocati ons ori the Pl arit Pl'0Per tv can be used to re =ord free field ~rourid motion.
However i because of the comf le:<
toPoeraPhvi it is e;;Pe:ted that recordiries at these three "free fi e 1 d" 1 ocat i ons maw be s igriificant 1 v di ffererit. This Pr'ob 1'em shoul d be i rives t i iated bv comPar iris both time-his tor'v rriotiori arid r esPorise sPectra of the motiori at these three 1 o:atioris.
I f these thr ee motioris are sierii ficantlv differeriti =onsideratiori should be driven to FEM analysis of
P
ACR'=:."::vbcommittee Meetiriei Mar=h 1-"A)9'".
differerit~
=orisider ation shovld be riven to FEN analrsis of the elan't site iri ari attempt to uriderstarid recorded motioris arid to e;<tend that wor 4 to study'oi l-str.vctvre interaction effects.
(=:)Calculated Ground Motiori It is understood that ari estimate of site free motiori wi 11 be made star tine with ari assurried fault motion. It is sveeested that ari attempt be made to =alcvlate free field motiori of small re=or ded earthsvaf:es measured at the site in order to assess the a=:uracil of the arial vtical r rocedvr e.
2, 6 FIRE;AFETY COtl'=:IDERATIOhl'=
The iriterrelatiorishie betweeri fire started t v ari earthsual:e arid elarit safety shovl d te eval vated.
For e;<am~1 ei a cerami
=
high vol tave irisolator could fail startirie a fire.
How would el arit safety be:omrr omi sed?
- 7 EMPHASI'=
The orieirial seisaii
= design of the DCPP was based on a ~eak sr ovrid a=eel er ation of 9.
G. Reevaluatiori of this motion iri light of the Hoser i favl t arid additional ear thsuake data wil 1 pr obab 1 v 1 ead to aria 1 uses o f se i smi c mar sii ris based on ir ovnd motions from 8.
G to 1.8 6 weak erovrid a::el eratioris.
As a r esvl t Code al 1 o~'at le stress cr i ter ia nial
- t. e exceeded at some 1 ocat I olis
~
However i be =avse of the erier~z absor bti on
- aPabi 1 its of du=ti1 e metal s i failvr e of ducti 1 e components or str uctvr es is riot evre =ted. Fail ur es of anchor s~
mater ial s with low dv=tilitv and
=oritr ol systems is much more libel v.
Emphasis should be >la:ed ori these failure modes.