ML20133M786

From kanterella
Jump to navigation Jump to search
Discusses Testimony Before Congress & Commission Re Probability of Earthquakes & Five Plant Show Cause Orders
ML20133M786
Person / Time
Issue date: 05/10/1979
From: Bill Russell
NRC
To: Eisenhut D
NRC
Shared Package
ML20133M133 List:
References
FOIA-85-301 NUDOCS 8508130261
Download: ML20133M786 (2)
v • d • e


Text

~

  1. UNITED STATas

/ /

y ,

NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20586 g -t

% ,,,,, # May 10,1979 NOTE TO: Darrell Eisenhut FROM: Bill Russell

SUBJECT:

TESTIMONY BEFORE CONGRESS AND THE COMMISSION CONCERNING_

PSDBABILITY OF FARTHOUAKES AND THE FIVE PLANT SHOW CAUSE

_0RDERS

1. During the May 3,1979, Commission briefing on Maine Yankee, the
2. During the April 26, 1979,' Commission briefing on the five shutdown plants, no discussion of probability or specific recurrence interval occurred. The staff did indicate that the risk associated with the MaineYankee DBE was a factor of 25 higher than that which would be associated with current requirements.
3. During the March 27, 1979, Hart Authorization Hearing, the five plant shutdown was discussed but the probability of earthquakes was not discussed.
4. During i.he March 21, 1979, Bevill Hearing extensive discussion occurred on the probability of earthquakes. The 200-400 year recurrence interval for the operating basis earthquake was identified. It appears that about one third of the hearing involved this topic.
5. During the March 19, 1979, Udall Hearing the prepared testimony included a discussion of eastern U.S. seismicity. The formal tran-script has not yet been received by the NRC. The prepared testimony, however, relates Maine Yankee to an Intensity VII DBE at the higher end of 10-3 to 10-4 probability of occurrence.
6. During the March 16, 1979, Hart Hearing a brief mention of overall earthquake probability occurred. A 200-400 year DBE was discussed.

The DBE was identified as having 1,000 to 10,000 year recurrence interval. No plant specific earthquake information was discussed.85-303 PR e u.-

um- - - - - , ,

. ~

2-l

7. During the closed Commission meeting on March 13, 1979, to discuss the proposed Show Cause Order for five plants, no discussion of earthquake probability occurred.
8. I recommend letters to each congressional committee which identifies the recently revised estimate of the design basis earthquake at Maine Yankee. This should be completed on a priority basis.
9. The Abnorr.a1 Occurrence Report on this event which was approved on April 30,1979, has been revised to delete reference to probability of earthquakes. I have discussed this revision with the Commissioner's

~

. Technical Assistants.

h Bill Russell q E. Case, NRR R. Denise, DSE W

es=

(

^

' I~ ]~ ,

h3-

.f. e.;;. . . \,g .. v.y..-.

,* , }g, .m

!y, .p.

g.. 1 _. u,.

gf . .

. -y

. ' ^

~ . .

~~ . ,

4 APR " R 197S '

~~ ~., :. I

! c. le .l .

HEMORAHDUll F0P.: Commissioner,R. T. Kennedy PflM?T . ' - -

~ '

. g .,

THRU:. . ,. .

y :ee l V. Gossick, Exei:utive Director for Operations FR0ft:

Harold R. Denton, Director? ~ '

' Office of Nuclear Reactor Regulation '

~.

~

SUBJECT:

, VALUATIONS OF FIVE NUCLEAR POWER PLANTS ;

This is,in response to your menorandum of harch 14, 1979. p .

g. .

' The seisnic ' analysis metho'ds for the five affected plants' were .

2

~

. reviewed in some detail, especially at -the OL stage 'of review, and' .

found to be acceptable. However, the staff in its review did not; .

explore trie spatial (intramodal) method of. combination used in the-The. review was sufficient to -

dynamic analysis of.systen piping'. disclose that acceptable methods w .

- sponses, but we can: find no indication in the, agency records that -

the intramodal method of combination was described or questioned .

on any of the five plants. Records for' other plants of Stone and

' Webster desi'gn that' we 'have reviewed in recent years 'do contain .

descriptions of acceptable methods for these spatial response  :

combinations.' . In addition, ,the , enclosed describes the present ,!

state of verification of stress analysis met. hods. .

. 1,. -

A brief description of.how our seismic design methods have evolved

- follows. 'In the early years of nuclear regulation, prior to 1967, ~

there were no fomal regulations or.guidahce on seismic design - .

methods.

The state of the art of seisciic design during this time  !).

. was perhaps best described in a document entitled " Nuclear Reactors . '

j~

and Earthquakes" (TID.-7024) issued in August 1963, by the U.S.

Atomic Energy Commission. The report reflected the practices .

employed in the design of governmeht-owned reactors at that time..

, Applicants for AEC l . icenses were made aware of the existence of'  ; .

such documents and' instructed to employ them in design of their nuclear power plants. - The methods used for seismic design in.the .

period prior to 1967 were .the so-called equivalent static methods..

In the equivalent ' static load method of anal'ysis a single static force is applied 'at the center of gravity of the . structure or com-ponent. In using 'the method, the. designers usually took the peak of the calculated dynanic respons.e of the st.ructure, multiplied . . . . . . .

.e -=

esoetsooL3

',' yi. fQ .. '. ; f -[. w } : ;. *. .

^

f, n L. y..,_.,:  :..;.: -i r 4 .4 p.y 3 g .~. ,g ;

r.
:y. .

~..

~

t ~ - 2-- -

..Commissionerw... R.".-sT., Kennedy;F.$;'  : .Wil'N-Iv. . . .' .

.m . e .;

~-

-C _ . qq.bh. yy.;.; ., ; f. u -

. . . ; . ..u. . :.. .; w :. . . .

. . .~ ..

it by sone factor bene. . .. . . . weTi.5'and 2,"and 'then' calculated an

. '. equivalent static . force. ' This'. single force was intended to represent the' forces dueto the inertia"of the structure and - -

the amplification of thbse. forces due to the' dynamic nature. - * .

-. j of the loading. '.Although thi.sf approach is suitable for systems .

.:. . . , .. of simple geometry,. it;was found.to 'possibly underestimate the '

' seismic re.sponse of complex s'ystems in:,some cases and to over * - . f

. estimate in othdrsc.'F,1-6V.' .".1371. ? ~

,. . .-;.. & M C-ll'. ;?. . y ' [ ,, l ...?. W . ?

- -~

'.; ~, ff'(' Starting about 1967,;. various ex;ierts in the field of seismic .

design, most notably Dr. Nathan Newmark at the University of .

~. Illinois, published papers demonstrating that advanced dynanic

- that were a technological spinoff from th'e. - , .

. analysis aerospace techniques 'ould be applied to.the seismic design of . .' . . . '

~

industry ~c -

. . structures. The " application of these. advances in the state of . * -

. ,the art to nuclepr pl' nt adest'gn~was',' encouraged"and supporte,d by ' ,

~the AEC .regu.latory staff be'cause they. pemitted better character-

-ization of the actual response of nuclear. power plant structures. k .

~

j and systems.to,an earthquake. It'js 'also ,important to note' that .

- the use of these more advanced dynamic . analysis techniques. inu .

design of complex structu'res like' nuclear power ' plants .was -

i feasible by, the late 1960s because of the increasing availability .

.of computers.with'su'fficient ' capacity and . calculating speed. i g

j .

.. y , ' . , .'

- When the staff began to require dynamic, analysis in the design of -

j structures and components for seismic loading in about 1967, the

p. methoas and ' practices employed by . industry were based on the e available technical literature and on what had evolved.as accepted ~

engineering practice in the. field of dynamic analysis as it was

~

, ,. appplied outside the nuclear industry.' Inherent in the- dynamic . -

,. analysis techniques was the recognition that. actual structures 'and

- systems would respond to 4(earthquake in several simultaneous mg. des of vibration.. This meant that.a mathematical method was .

necessary for combining the spatial fintramodal) components of the < , .

seismic response at a given point in a1 structure or system to .

~

determine the total response. However,- the regulatory staff .

. guidanc.e on. acceptable techniques of dynamic. analysis for use in license app.lications sas limited to basic criteria such as earth - ' '

quake and accident loading combinatio'n's, allowable. stress and 2 -

defomation limitsand damping. values;' These criteria'were' com . ~.

municated principally through the quest' ion and answer process. used _-'

l ',

in.the staff review of an application. 'The NRC records disclose - -

c, .

~

..e

.~

g e

. e.. e

.e- . wee. -M=

- - - ~ - ' - - - - - . -.. , , . . - _%.,,, . . . _ . , . _ . . , . . , _ . _ , ,

/

E *. . .

2'. . . '..- ,-

_.. 9, r . .b. -; ..

s- : . ,  ;,,,

N

-5. :ff.,S'~N - *- ~

'S -

D.lg53kOM[

.'. M . ; . n . ., l-

.'..s$. .9

.  : . , :Y. . __ j y .; c '

' ~ S.7..' . ". Commi ssioner R. t.~ Ke'nnedy ' .

.? .

~

.' .',.  ?. .

a: .- ., .

1 j'

.that' no criteria were issued at the detailed level of analysis ' ~

, .;~ involving the combination of spatial response components in .

[;

' f _. -; piping

, d' ., ' -

or structures in these early years.

~

  • O ' . i ~ Beginning about 1967, consulting organizations' sere retained by '

y... .

the AEC regulatory staff. to assist in the evaluation of seisnic - -

i d esign criteria for most plants, . including Maine Yankee, Surry, ,. . .-

'. F.itzpat'rjck.,,and Beaver Valley. Expert and. nationally recognized '

  • -- consultants were retained under . contract with the AEC . regulatory

, , { . staff,in ]ieu, of hiring staff members with cor.) parable expertise. , ,

.., 1., g ... , . - , -

In the period 1970-1974 the staff was' enlarged to include personnel

~

with expertjse'in dynamic. analysis,' and a number of consultants ,

were em' ployed to assist in defining more.' specific requirements for

. - - .- - seisinic analysis. During this same. period of. time there pas a .

great. deal of' activity in the engineering community in the develop- .

. ., ment of : techniquesfordynamic: analysis:of nuclear power pla'n ts. .

. A number of' studies were undertaken by engineers in both academic and industrial circles 'to define' the-aprilicability and limitations ,

of tthe' analytical techniques that were coming into use, including

~

, .the sub,jects of . modal and spatial response combinations. . From our regulatory point of view, this period culminated when the essence of these efforts was codified in HRC Regulatory Cuide 1.92

- ".Conponents of Modes and Spatial Components' in Seismic Response .

~,.

Analyses" first publishe.d in 1974 and revised in -1976. The guide s'-

is now in routine use in the licensing proce,ss and. treats fully .

. the' method of response combinations of concern in the five affected plants. - '

4 - '

l

~

Odginal Signed % .

, Roger S. Boyd . . ..

s .~.

l .

. Harold R. Denton, ~ Director.

.f. Off. ice .of,. .Huclear Reactor Regulation'. .-

DISTRIBt/rION . -

l

Enclosure:

ge 11 3 - , M ".'

"Present State of Verification , PSS '

l

'of Stress Analysis Methods" G-~c.5R'CEM @ Q -

^

l . . _

[

cc:. Chairman Hen,drie'; - - .

hn. .

.:. ' See attached li.st' for l

Commissioner Gilinsky ' . D -@ '

distribution.

Commissioner ' Bra'dford' G. -

l Commissi'oner Ahearne -

'. NRR:DSSD NRR: DSS ' OFLD -

~ '

l A. Kenneke, OPE .

L. Bickwit, OGC RMATTSON* ,,JKNIGHT*

. /) ,.

l l

[.

- ' S. Chilk, SECY - 4/9/79

  • SEE PREVIOUS YELLOW FOR CONCURRECES 4/9/79- # /79 '

F_ r . Drwwoe. OC A -

NRR.hgfouchard OPA

--

  • m c=*'* .rntr41he:pab ....MP.EE..-- ..M R 1.@.. .%i@JA..~.. .... . D.I.R ,,,,,,,, ,,, ,E,D,Q,,,,,,, , , ,,

,,,,,,,,,, DFBu. EGCa.9e) - .* HRD on LVGossick .

g. ......................... .tM..Cr.u..t..c.h...f.i.e..l.d

! f,.

43

......../. 3 0/. 79

. 3

....../. 3. 0/. 79 .

. . . . . . . . . . . . . . ./. .. .'. ./. . 7. 9..[, . . g. .../.. 7.. . 9.........

. .M...f2j./.. 7.9.~........

. .../....../..7 9., . . . . . ,

asc sonM 314 (M4 NBCM ande - 5 . . W u.a. e vesemen, ,=.c no eerde un u o * ,ee . .* -

E- .

.. ;.k. e a t: ,nav a:% r. .

. . . .n......~. ,.- .

c . .... . .?

. 2 *,

  • .
  • J ,, ,.

W ,+

DISTRIBUTION Central Files HRDenton EGCase FMiraglia DCrutchfield '

DBunch RMattson JKnight -

OELD ED0-5606(Groff)

ED0-5606(GEretter)

KCornell TRehm HShapar

< DEisenhut O

d b

i 2

9

\ s v

  • ** *
  • wme * =ge qm_,,e,, , = _,, ,,

-- --n , -

, - . - - - - , - -w - -

m - ,, -m ,,,-.e--,, - , ---- -- n-w,-

Retrieved from "https://kanterella.com/w/index.php?title=ML20133M786&oldid=2878587"