ML20151H179

Board Notification 82-04 Forwarding Info Re Pressurized Thermal Shock

ML20151H179
Person / Time
Site:	Diablo Canyon, San Onofre, 05000000
Issue date:	01/20/1982
From:	Eisenhut D Office of Nuclear Reactor Regulation
To:	Ahearne, Bradford, Gilinsky, Palladino N, Roberts NRC COMMISSION (OCM)
Shared Package
ML20151H182	List: ML20151H179 ML20153G933
References
FOIA-88-99, TASK-AS, TASK-BN-82-04, TASK-BN-82-4 BN--82-04, BN--82-4, NUDOCS 8202120089
Download: ML20151H179 (2)

Text

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2 4 O!STRIBlff!ON Central File WJ0ircks JMUMY 30ast OL:L Reading D. Johnson RLTedesco JKerrigan DGEisenhut/RPurple BYoungblood ASchwencer DOCUMENT CONYRC' FMiraglia NRC POR Ett)RAllDUM FOR: Chairman Palladino EAdensam TERA Commissioner Gilinsky JRM111er NS!C Cosmissioner Bradford PW1111ams Tic Cosmissioner Mearne OCLD Cosmissioner Roberts Ol&E(3 Divisio)n Directors FRON: Darrell G. Eisenhut. Director Ol&E(3)

Division of Licensing ACRS(16)

Office of Nuclear Reactor RepJ1ation HRDenton/EGCase

SUBJECT:

INFORMATION ITEM - RECUlf INFORMATION WITH REGARD TO PRESSURIZED THERMAL SHOCK (BQARD NOTIFICATION NO. 82 04)

In accordance with present NRC procedums regarding Board Notification the attached information is being provided to the Connission.

Copies of this infonnation are being sent to the Atomic Safety and Licensing Boards for Diablo Canyon Units 1 and 2 and San Onofre 2 and 3.

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og Darrell G. Eisenhut. Director Division of Licensing y ,,

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l Office of Nuclear Reactor P4904t{o,n '. ..

Enclosure:

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Hemorandum dated 11/03/81 .' /

cc: SECY .

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OCC OPA E00

Contact:

Janis Kerrigan, NRR 1291

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l MEMORAMDUM FOR: Chairman Palladino Commitssioner G11tnsky consrissioner Bradford Ccamiissioner Meame Cosmis 1oner Roberts FROM: Dart 11 G. Eisenhut. Director Division of Licensing Office of Muclear Anacter Regulation

SUBJECT:

INF0DMT!0it ! TEM - RECENT INFORMTION WITit REGARD TO PRES 5URIZED THERMAI. SHOCX (BOARD MOTIFICATION NO. 80-04)

In accordance with pmsent NRC procedures regarding Board Motification. the attached information is being provided to the Coeusission.

Copies of this information are being sent to the Atestic Safety and Licensing Boards for Diablo Caryon Units 1 and 2 and San Onofm 2 and 3.

Darrell G. Eisenhut, Director Division of Licensing Off!ce of Nuclear Reactor Angulation

Enclosure:

Memorandas dated 11/03/81 cc: R. Tedesco

8. Youngblood A. Schwencer F. Hiregita E. Adens as J. Miller M. W111t us

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• UNITED STATES i

• NUCLEAR REGULATORY COMMISSION .

, L, W A$ MIN CYCN, D4. 20$ 55

\ Hovember 3.,1981 ,

C776CE OF THE -

CHAIRMAN , ,

NOTE T0: Tom Hurley FROM: - Ja '

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SUBJECT:

- HEE ING .. ON PRESSURIZED THERHAL SHOCK On October 27, 1981 several Commission'ers' Technical Assistants met with staff members of the House Committee on Interior i and insular Aff airs and Dr. George Sih of Lehigh University.

Dr. Sib'provided some draft written remarks on thermal shock during the meeting. I have attached these for your information.

D r. Sih stated that he is willing to meet with the HRC Staff to discuss his views. .

cc:

Ed. Abbott B. D. Liaw

• Tad Marsh Gary Zech John Austin Ed Case ,

, Roy Woods D. Ross H. Yagins C. Strpan N. Randall Of MOO 2 !9 XH 9 Pf'

. . 'G. C. Sih

• * " Institute of fracture and Solid Mechanics '

Lehigh University .

Bethlehem, Pennsylvania 18015 .

1, BACKGROUND JNF,0RMTION .

This document is concerned with the overcooling of reactor vessels and the progress'ive embrittlement of the material due to neutron flux er.6rittlement. '

l The cerraents are based on discussions with individuals from NRC and information .

L co'ntained in the referenced technic'al documents.

11. THE STATE OF ART -

Based on a number qf.,recent technical documents (1-3) dealing with the in- -

fluence of therrmi shock on nuclear reactor vessels, it becomes irnmediately evi- '

dent that there are great amounts of uncertainty associated.with forecasting the  !

integrity of the RV. Aside from the uncertainties associated with data collee- I tion on vessel fluence, irradiatie'n temperature, etc., there is the uneasy feel- , f 1

,ing that the current methodology might not be adequate. In a recent b:fefing to [

the llRC Co.raission (1) on Sep'tember 15,1981. Dr. T. E. Hurley from flRC ques-tiened whether RT NDT is the proper criterion. Moreover, what model should be used to calculate RTHDT 7 Indeed, if RT is to be adopted as an indicator for HDT the safe operation of RY, it then certainly should be identified with the mode

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t of failure, .

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Theutilities(2)viewthethreatofthermalshockasalongtermproblem lf I

tha t does not require irt. mediate actic... Eabcock & Wilcox (31'J), k'estinghouse  ![

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l' ths.r.:st i..portant technical it, sues facing the nuclear pester pier ts it h/, bt '.

thtre is, still time to tihe a, systematic look t.nd develop a cost efft:-t'.'t pro ,

cedure to rt .edy the ;,roblem. Anslyses are being perfor.ud pretu .!bly t.o Biter- .

mine the safety cargin of existing vessels.

Returning to the current methodology on radiation-damage of ferr:itic steels, the objective has been to establish safety margins on certain parameters-for the spectrum of anticipated and improisble accidents considered for nuclear .

reactor. ' pressure vessels. There are, however, a number of i'mportant que.stions" that remain to be considered:

(1) The tnost comn test for radiation damage of ferritic saels is the .

Charpy V-notch even t$ougin the test has many lim,itations. Cen the Charpy data be correlated with failure behavior of the reactor vessels? . ,

(2) A Charpy size specimen that yields relevant damage data would be I

ideal for surveillance tests since large specimens pose problems in a reactor ,

vessel. Can the current approaches such'as J-integral or COD translate the sub-size specimen data to the design of full size reactor vessels?

(3) Can linear elastic fracture mechanics (X;g, Kj ,) or elastic-plastic I (nonlinear) fracture mechanics be used to quantify effects of flaw size, shape i ane orientation, on loads?

(4) is there a site effect influencing brittle fracture of low and medium strength alloy stecis? .

(5) 1' hat is the effect of varying the irradiatise te perature on radiatien ca age?

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_ - . _ _ _ _ . . _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ _ _ , _ , _ _ _ _ _ _ _ _ . m____..,__ _ _ _ _ _ _ _ _ _ _ _ - _ ._ _ _ _ _ _ _ _ _ _

,,,- , 6 1:he t s - e . .gn cance,o! rans t on t.p..a ure an.,w..a ac ors-

s shifts in transition temperature?

, (7) Hovi critical tre the redu:tions in up;ar-shelf ar.sr9tes d.:6 to r.ru-t,on dose? .

Attempts have been made to relate Kjg with the upper-shelf Charpy V-notch (CVN) values with the objective that..large brittle . behaving tests.for Kjg can be correlated with small ductile behaving upper-shelf Charpy energies. Such an .

exercise is self-serving in' that it does not shed light on how specimen data ',

- could assist the design of large size vessels. The basic problem is one of  :

translating the combined effects of geometry load, material and radiation en-

' vironrnent measured in the laboratory to predict the behavior of strue.tures opera .* ,

ting under a differeni, sTt'of tenditions. ,,

To be reelized also is that the A5)iE Boiler and Pressure Vessel Codes de-

' veloped more than two decades ago are no longer adequate and are badly in need of revision. Many of the structure failure problems in nuclear power plants are

- not new. . In. fact,- they were never understood and solved, and-4re inherited frori .

i- the conventional power plants. Because of the potential health. hazard associated with nuclear power plant failure, there is the urgent need to rev% the basic philosophy that gyldes the overall design of the nuclear vessel structure. Many l

of the dif ficulties are not being overcome in an intelligent and systematic nanner.

l There is, in fact, no truth in any of the proposed 'tilure criteria adopted by t,he ASHE BPV Codes, Conaiattrey in the basic concert and rnethodology, hwever, i

have to be preserved 50 that knowledge and experirentel data can be accumuiste,d to est,ablish predictite capability. In this respect, the present design philos. ,

' t

'Only 50 years ago, TV a'nd jumbo jets utre unheard of. Our basic understanding -

of science has fallen behind the rapid space of technology advancement.  :

3

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, . Iophy*deall'ng'with ,the application of fracture r.echanics is lacking in two re ' .*

spe c't s :

(1) Assu:Ing that . irradiation alters the fracture toughness' K gg of'the ,

c.aterial, the strest and failure analysis es,st ne,cessarily account (pr ac4erir.4, nenfu:xse.neby because neutron flux causes r:nunifora darage of the.raterial . . .

through the vesst1. . ',

(2) Nonlintar response implies ;dogrea.livt de.mst of the rd.erial' as it , ,

is being loaded mechanically, thermally and/or by tiradiation. The damage 1.s "

cumulative and depends on the history of loading. By definition, the stress,'

' ,. and failure analysis ryst be carried out in tanden foe each incre. tent.of loading.

and cannot be perfom4 separately ce independently .

• Ill. ,THE BA51C PROBLEM Of TlHC AND $12( [FFECTS ,

Unlike social and pollt'ir.41 science..engtntering science must follod a set  ;

of strict disciplines 1sid denen by the laks.of physics.' Codes ein serve only

', as guidelines and become meaningful and reliable when the technology 18 well established and understood. The prediction of nuclear reactor vessel failure unfortunately does not fall into this category. The inability to predict the failure behavior of full site structures from specimen data is not unique in .

reactor vessel design. This is a fundamental problem involving the scaling of I l ..

l tire and site between the prototype and :cdel that ur.dergo progressive dar. age .

I  !

- i This procecure is not being folleited in many of the current analyses that claim i a to include nonlinear ef fects.

"The leis of georatric stallitude used frequently in atredynamtes does not apply l Lo V.e redelin9 of nuc114r )4ssels nihose dardje is cv"iv14tive in nilui'e and in j l balltilly nonlinstr. l l

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• in view of the lirited data basis for raterial da aged by irradiati:r.

and the lack of a reliable theory that could extrepolate in time, no confidence I can be placed in estinating the radiation dar.4ge rate of reactor vessels, te-cause neutron flux will interact intirately with raterial, leading and geometry, test specimens should be carefully designed on the basis of a theory that can.

isolate these individual effects. Extrapolation of approximately one order of I

c.agnitude is a realistic expectation. Continuous monitoring of irradiation data for two to three years is needed for extending the predictive capability to 20 '

years.

) .

Sire it.ects l (2) -

! The current failure criteria based on J. integral and C0D are specimen site dependent and tre fundamentally unsound: The objective of any anaiysis is to, demonstrate its ability to correlate two independent sets of experimental data pre f arebly.fros.the prototy)e *and mods), tihat shouid be pr4 served. in the model is.the (Eilme r,dc' so tha't a realistic life prediction of the prototype can be  :

ma d e .- This reqtires*the fira comitment of 4 ' suitable failure criterion. The capability of bet.: able to simulate failure modes can be demonstrated by testing l

two vessels,fr<h My diff ring i' ':::t in one or.cer of ragnitude in site.

Once the  !

tensitivity of the relevant parameters that can alt.er failt;re redes in the proto.

type and 'mo' del is known, the tr.e confidence level of vessel operation can then be estab)ished.

• fo the writer's know1.dfe. this is not being done at the present because of the 1eck of a suitable criterion. '.

5

As c.entioned earlier, the problea of progressive rateriti dt..sge is a complex process as it involves the coupling of, geometry loading, raterial and.

environmental condition. In particular, the effect of neutron flux on the [dtgra-dation of structural components neai the nuclear core is not well understood. ,  ?,-

The current design approach of extrapolating results from simple uterial testings ,

is not suf fielent . Neutron absorption,must be considered to interact wl,th tem '.

perature and deforntion nonuniformly throughout the irradiated caterial. Jt is .

not dif ficult to fomulate theories that account for the cou'pling of neutron flux, temperature and mechanical . deformation. Suitable experiments my be devised to determine'the necessary constants. ,

ly. ADDITIORM. COP.4ENTS .

Obviously, there is a whole range of additional things that need to be con-sidered with regard to the therm 1 shock problem. Although corrective measures can always be taken as a short term solbtion, there is never.. sufficient time to- '

resolve the long term problem. Code allowables and rules are established'so that they can be im,) roved. They need to be scrutinized from time to time as new re-search concepts and results becce.e available for application.

f ast neutron irradiation is kno=n to cause damage through dislocations of the atoms of the e.etal and speeding the resulting vacancy dif fusion reaction. The alterations in the physical properties of nuclear reactor steels by exposure to these high energy neutrons are riessured by changes in yield strength, fracture toughness and notch impact transition temperature. On the bases of thete tests, a r.arked decrease in ductility and fracture toughness are observed. ' The magni-tude of these changes, however, is a function of the raterial, the absorbed neu-tron irradiation and the temperaturt and it interacts with the local mechanical stress. There is presently no suitable theory for determining the infivence of radia tion and the design relies on empirical data.

6

_ . . - ,-m . - _ . _ . - . - . . _ _ _ _ _ _ _ _ , . - _ _

. fhe material characterization and structural application aspects of nu. -

clear vess'el design should be emphasized not only in solving specific technical problems but also in establishing a sound philosophy of* design. The nuclear ves-

=

l sei technology .s of sufficient national interest and deserves such a recogni . *  ;

tien. In this respect, a more critical review of the NRC long range research plan (5)concerningfracturemechanicsisinorder. The choice of fai*ure or fracture criteria should not be taken lightly but must be carefully considered *,

particularly for charactertring material dae. age behavior due to irradiation, for instance, the strain . energy absorption to failure (6) has been shown to be an effective criterien to characterite the embrittlement of metals in hostile envirenments such as radiation. The Hangarians (7) have also used this concept for assessing the degtacnton of reactor vessel. materials caused by neutron flux impingement. ,,

Y. RE F E REh'C ES .

, ()) Comission Briefing on "Pressurtred Thermal Shock of Pressure Vessels" by T. E. Murley, Septemb,er 15, 1981, j .(2) Sux..ary of Heetings with PWR Owners' Group and Vender Representatives on "Pressurized Therr.a1 Shock", by SW (7/28/81); Westinghouse (7/29/81) and CC (7/30/81).

i The mere agreement between theory and experiment on a particular specimen or structural component is not suf ficient. Predictive capability should be 4<+M in terms of site and gecc.etry independence so that specimen data ,

can be translated to the design of full size structures.

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[ ,[ 3 ].

• Evaluation of the Threat to PHP. Vissel Integrity Posed by Pressurized .'-

' ' Thermal Shock Events" by R. C. Kryter et 41, OP.NL/TH 8072, October 7,1981.. -

(4) "E.xperimental 'Tracture Mechantes: Strain Energy Den.".ity Criterion", by  ;

l ,'

,- G. C. Sih, Vol. 7, Hechanics of Fractur,6.,, 51jthof f and Noordhoff Ir.'terna , ,

tional Publishers. The Netherlands (in Press). '. .

(5) Extract froan titlRIG 0740 on the "HR'C Long Range Research Plan" for the Materia'Is Engineering Branch of the Of fice of Nuclear Regulatory Research, March ,1981.

(6) "Strain Energy Absorpt an as a railure Index for Materials.5ensitive to *

. , Interstitial - Dislocation Interactions", by P. J. Pankaskie,' Proceedings in

International Sr.npos.iun on Absorbed Specific Energy and/or strain Energy Density Criterion, edited by G. C. Sih, t. Caoboly and F. Gillemnt. Sijthoff and Noordhoff International Publishers The Netherlands, pp. 313 317, 1981.

(?) "Some Aspects of Evaluation of Defects in Pressure Vessels", by F. G111emot, Proceedings of the first International 5pposium on Defects and Tract,ure.

edited by G. C. 5th and H: lorski',' Sijthoff and Noordhoff International Publishers The lietherlands, pp. 165-176, 1981.

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PUBLIC UTILITIES COMMISSION ses VAN Ntl$ aW1 nut

$4N f e ANCISCo. Ca 94102 3299 February 8, 1988 IPiwC;.i 0F listChMATat ACT REQUEST Mr. Donnie H. Grimsley, Director [d.2"A -Y /

• T f Division of Rules and Records Office of Administration and Resources g ,y '

Management U.S. Nuclear Regulatory Commission Washington, D.C. 20555 RE: FoIA Request for Staf f Requirement Memoranda

Dear Mr. Grimsley:

Pursuant to the Freedom of Information Act and 10 CFR Part 9, Subpart A, "Freedom of Information Act Regulations", please make available at the Commission's Washington, D.C., Public Document Room single copies of records in the following categories:

A. All records written or signed by Richard Vollmer and sent to or copied to Harold I Denton between August 1, 1981 and '

December 31, 1983, which refer in any way to Diablo Canyon Units 1 and/or 2 or to activities conducted at Diablo Canyon Units 1 and/or 2 during this time. This request includes copies of any and all l attachments to these documents. '

B. All records written or signed by Richard ,

Vollaer and sent to or copied to Robert t Engelken between August 1, 1981 and December 31, 1983, which refer in any way l to Diablo Canyon Units 1 and/or 2 or to -

activities conducted at Diablo Can Units 1 and/or 2 during this time. yonThis I j request includes copies of any and all .

attachments to these documents.  !

l C. All records written or signed by Richard Vollmer and sent to or copied to Darrell Eisenhut between August 1, 1981 and j

, December 31, 1983, which refer in any way L to Diablo Canyon Units 1 and/or 2 or to t activities conducted at Diablo Can f l Units 1 and/or 2 during this time. yonThis l request includes copies of any and all i attachments to these documents.

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• Mr. Donnie Grimsley ,

February 8, 1988 Page 2 D. All records written or signed by Darrell Eisenhut and sent to or copied to Harold l Denton between August 1, 1981 and l December 31, 1983, which refer in any way '

to Diablo Canyon Units 1 and/or 2 or to activities conducted at Diablo Canyon Units 1 and/or 2 during this time. This '

request includes copies of any and all attachments to these documents.

E. All records written or signed by Darrell Eisenhut and sent to or copied to Robert Engelken between August 1, 1981 and December 31, 1983, which refer in any way to Diablo Canyon Units 1 and/or 2 or to l activities conducted at Diablo Canyon i Units 1 and/or 2 during this time. This request includes copies of any and all attachments to these documents.

F. All records written or signed by Darrell Eisenhut and sent to or copied to Richard Vollmer between August 1, 1981 and December 31, 1983, which refer in any way to Diablo Canyon Units 1 and/or 2 or to activities conducted at Diablo Canyon Units 1 and/or 2 during this time. This request includes copies of any and all attachments to these documents.

We request a waiver of fees pursuant to 10 CFR 9.41 because the  !

docusents will be used by a state agency as part of an official (

investigation.

[

If you or any members of your staff have any questions concerning l this request, please contact the undersigned directly by i telephone at (415) 557-0168. It is requested that, if documents are identified which are releaseable under this request, partial responses be made as appropriate. Your prompt attention to this i request will be appreciated. ,

Sin rely, 2/ .

teven Weissman Staff Counsel '

SWtbik [

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