ML20128M337

Informs of Review of Ucs Re TMI-1 & Oeld 850517 Memo Discussing Ucs Ltr.Ucs Ltr Does Not Warrant Further Commission Review

ML20128M337
Person / Time
Site:	Three Mile Island
Issue date:	06/07/1985
From:	Chilk S NRC OFFICE OF THE SECRETARY (SECY)
To:	Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
Shared Package
ML20128K764	List: ML20128K757 ML20128M331 ML20128M337
References
NUDOCS 8507250294
Download: ML20128M337 (3)

Text

.

/

y"

, #';o UNITED STATES

,7, NUCLEAR REGULATORY COMMISSION

y. .E W ASHINGTON. D.C. 20555 e, I

/ June 7, 1985 OFFICE OF THE SECRETARY MEMORANDUM FOR: William J. Dircks, Executive Director for Operation FROM: y Samuel J. Chilk ccretary

SUBJECT:

APRIL 18 UCS LETTER The Commission has reviewed the April 18 letter from the Union of Concerned Scientists (UCS) regarding Three Mile Island, Unit 1, and the May 17, 1985 memorandum from the Executive Legal Director discussing that letter. The Commission does not believe the UCS letter warrants further Commission review, and is referring it to you for an appropriate response by letter to UCS.

cc: Chairman Palladino Commissioner Roberts Commissioner Asselstine Commissioner Bernthal Commissioner Zech OGC OPE

.h)./

m....... p. 04

,- f.,

BB872;g;pc;g;ggg, P

4 E D O -- 000702

th AE?ft

1. 'o UNITED STATES 8" e NUCLEAR REGULATORY COMMISSION

( , E WASHINGTON, D.C 20555 June 7, 1985

%.....d'

. CFFICE OF THE SECRETARY MEMORANDUM FOR: William J. Dircks, Executive Director for Operation FROM: Samuel J. Chilk cretary

SUBJECT:

APRIL 18 UCS LETTER The Commission has reviewed the April 18 letter from the Union of Concerned Scientists (UCS) regarding.Three Mile Island, Unit 1, and the May 17, 1985 memorandum from the Executive Legal Director discussing that letter. The Commission does not believe the UCS letter warrants further Commission review, and is referring it to you for an appropriate response by letter to UCS.

cc: Chairman Palladino Commissioner Roberts Commissioner Asselstine Commissioner Bernthal Commissioner Zech OGC OPE Ret'd Cl

/O

%. . . .'b?i. *~ .m. . .Q4=,M 0

4 EDO -- 000702

W

+ p 'tr d oq'o UNITED STATES

(  !" o NUCLEAR REGULATORY COMMISSION j E W ASHIN GTON, D.C. 20555

'*,.....# June 7, 1985 OFFICE OF THE SECRETARY MEMORANDUM FOR: William J. Dircks, Executive Director for Operation FROM: Samuel J. Chilk cretary

SUBJECT:

APRIL 18 UCS LETTER The Commission has reviewed the April 18 letter from the Union of Concerned Scientists (UCS) regarding Three Mile Island, Unit 1, and the May 17, 1985 memorandum from the Executive Legal Director discussing that letter. The Commission does not believe the UCS letter warrants further Commission review, and is referring it to you for an appropriate response by letter to UCS.

cc: Chairman Palladino Commissioner Roberts Commissioner Asselstine Commissioner Bernthal Commissioner Zech OGC OPE CO

% ...#p.,

.1".h/0 4. A' E D O -- 000702

~

NI N OF .

CONCERNED SCIENTISTS 1m c_-uma..... u.w. . s. mi . w.my.. oc ox. <md&%P

. is his eis April 18, 1985 GFFICE OF SECRETAR Nunzio J. Palladino, Chairman B C Thomas M. Roberts, Commissioner i James K. Asselstine, Commissioner l Frederick M. Bernthal, Commissioner l Lando W. Zech, Commissioner -

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 f' Gentlemen:

We were astonished to hear Mr. Clark of GPU Nuclear assert this morning, not once but repeatedly,--that the changes to the THI-1 steam generator tube - .

rupture procedures and safety limits discussed today were not driven by the degraded condition of the tubes.

We are enclosing for your attention the cover sheet sheet and two pages of the GPU Technical Data Report prepared to support the new procedures.

Please note that the section entitled " Introduction and Background" states as follows:

Since extensive circumferential cracking was discovered in

- approximately 1200 of the 31,000 tubes, it became clear that a revised set of procedures for dealing with both single and multiple SGTRs [ steam generator -tube ruptures].should be -

developed.

TDR 406, Rev. 3, p. 14 - _.

O The following page lists among the activities involved:

Define 1.lowable steam generator stresses during cooldown (either as cooldown rate or as tube /shell delta T).

Revise minimum allowable subcooling margin.

. Waive fuel in compression limits

. Develop emergency RCP NPSH [ net positive suction head]

limits.

Id., p. 15 -

= $ m

. - < r w w t p .1. c T ' ,

r ,  ;

., j

_2 Please also note that Mr. Clark and Mr. Wilson are on the distribution list for this document, which goes on to discuss the need for revising the safety limits in greater detail.

Thank you again for the opportunity to address you 'today.

Very truly yours,

/

f

,- Ellyn . Weiss General Counsel

Enclosure:

As stated. -

cc: THI-1 Service List .

e e

%s 9

+y W en h

a p

\

1

~

UNION OF .

l CONCERNED SCIENTISTS im c_um, i._.. u.w. . s. im . w.mi.,,_. oc os . <mngsp

. N N518 P5 l April 18, 1985 GFFICE OF SECRETtJ Nunzio J. Palladino, Chairman Thomas M. Roberts, Commissioner hCH James K. Asselstine, Commissioner Frederick M. Bernthal, Commissioner

~

Lando W. Zech, Commissioner .

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 ,,

Gentlemen:

We were astonished to hear Mr. Clark of GPU Nuclear assert this morning, not once but repeatedly,-that the changes to the 'INI-1 steam generator tube ~ .

rupture procedures and safety limits discussed today were not driven by the degraded condition of the tubes.

We are enclosing for your attention the cover sheet sheet and two pages of the GPU Technical Data Report prepared to support the new procedures.

Please note that the section entitled " Introduction and Background" states as follows:

Since extensive circumferential cracking was discovered in

- approximately 1200 of the 31,000 tubes, it became clear that a revised set of procedures for dealing .with both single and multiple SGTRs [ steam generator tube ruptures] should be developed.

TDR 406, Rev. 3, p. 14 ..

The following page lists among the activities involved:

Define allowable steam generator stresses during cooldown (either as cooldown rate or as tube /shell delta T).

Revise minimum allowa'ble sub' cooling margin.

Waive fuel in compression limits Develop emergency RCP NPSH [ net positive suction head) l limits.

I j Id_., p. 15 -

l S

0 e_. N V V ^ -"

i . .

-2 Please also note that Mr. Clark and Mr. Wilson are on the distribution list for this document, which goes on to discuss the need for revising the safety limits in greater detail.

Thank you again for the opportunity to address you 'today.

Very truly yours,

/

/

,- Ellyn . Weiss General Counsel

Enclosure:

As stated. -

cc: 7MI-1 Service 1.ist .

o O

@ *M e

4 e

e d

s.

~

• UNION OF CONCERNED SCIENTISTS im a...u..... u.w. . s. im . w.mi.y... oc mx . <md/mp

. R 18 P5 April 18, 1985 CFFICE OF Sgcagygg Nunzio J. Palladino, Chairman ghC Thomas M. Roberts, Commissioner )

James K. Asselstine, Commissioner I Frederick M. Bernthal, Commissioner Lando W. Zech, Conunissioner -

U. S. Nuclear Regulatory Commission

, Washington, D. C. 20555 f-Gentlemen: .

We were astonished to hear Mr. Clark of GPU Nuclear assert this morning, not once hat repeatedly,- that the changes to the TMI-1 steam generator tube .

rupture procedures and safety limits discussed today were not driven by the degraded condition of the tubes.

We are enclosing for your attention the cover sheet sheet and two pages of the GPU Technical Data Report prepared to support the new procedures.

Please note that the section entitled " Introduction and Background" states as follows:

Since extensive circumferential cracking was discovered in

. - approximately 1200 of the 31,000 tubes, it became clear that a revised set of procedures for dealing ,with both single and multiple SGTRs [ steam generator . tube ruptures] should be developed.

TDR 406, Rev. 3, p. -14 _

The following page lists among the activities involved:

Define allowable steam generator stresses during cooldown (either as cooldown rate or as tube /shell delta T).

Revise minimum allowable subcooling margin.

Waive fuel in compression limits Develop emergency RCP NPSH [ net positive suction head]

limits. ,

Id.., p. 15 S

.- - V ^  %-.

2-i Please also note that Mr. Clark and Mr. Wilson are on the distribution list for this document, which goes on to discuss the need for revising the safety limits in greater detail.

Thank you aga.n for the opportunity to address you 'today.

Very truly yours,

/

,- Ellyn . Weiss General Counsel

Enclosure:

As stated. - -

cc: INI-1 Service !.ist .

i -

1 I

4 4

e

=e

=p 'M S

6 e

4 9

f I

e

l h v. f 406 REVISION NO. b N

[ja ()j g ~.

TDR NO.

BUDGET j

. u 128006 1 81 TECHNICAL DATA REPORT ACTIVITY NO. *PAGE OF ECT: ' s -

a y a an nt pgg.1,, , ' ,; , .

DEPARTMENT /SECTION 1

~

RELEASE DATE 5 # REVISION DATE 1449*)

DOCUMENT TTTLE: . -

SG Tube Rupture Procedure Guidelines ORIGINATOR SIGNATURE DATE APPROVAL (S) DATE

, TUR)

!% *! e ~: - t I2.'1 98 W/ /**'W es -r i 2/,/,ry l '

/ ).. I h .

I APPROVAL FOR EXTERNAL DISTRIBUTION DATE

. l 41L%.mh k at i .i 3 -

- s Does this TDR include recommendation (sl7 Eyes C No if yes.TFWR/TR #

o' DISTRIBUTION A85 TRACT:

• R. W. Bensel' This document provides technical guidelines for dealing D. J. Boltz with single and multiple tube ruptures. A significant

'T. G. Broughton 2.mprovement in procedures vill result from reduction of

• 0 M. Campagna the minimum subcooling margin and RC pump trip on' loss

• P. R. Clark of subcooling margin, vaiver of fuel-in-compression I o J. J. Colitz limits, and revised RCP NPSH limits. Other benefits can I. R. Tinfrock be . derived from revision of the RC pu=p restart criteria T. L. - Gerber and from additional guidance regarding OTSG steaming and-R. J. Claviano isolation. Finally, revised guidance is provided fer

• R. W. Keaten preventing tube leak propagation. It is recommended C. Lehmann

• that the tube-to-shell delta T be limited to 70FO. -

• during tube rupture events.

D. T.141ghton ~

~

3. Leoiard _ ,

W. W. love d Revision 2 to this TDR included the following -

J. G. Miller

• recommendations f or procedural revisions, some

• T. Moran

• of which have already been incorporated in M. Nelson

• EP 1202-5. .

.. 7 '

• * ~

S. Newton o M. J. Ross

• 1. Is.olate the OTSG's on a measured or projected . . .

~

• H. 3. Shipman dose rate of 50 mrem /hr whole body or 250 mrem /hr D. C. Slear . thyroid dbse.

C. W. Smyth

• M. J. Stromberg

• 2. Stop the non-ES HPI pump if the RCS is cooling

• R. J. Toole more than 100F/hr. .

P. S. Valsh

• Dr. R. N. Whiteset

• 3. Priorities-should be spelled out in EP-1202-5:

• R. F. Wilson a. Minimizing SO{ has a priority over mini-mizing cooldown time. Og(

b. Keeping OISC level belov 95lll is less im-portant chan control of the RCS cooldown 'r 94092E9999 840517 rate.

k I r

y 1' PDR ADOCK 05000289 P PR

s l

T:ht 1,0o Rev. 3 Page 14 of 31 i I

I 1.0 I(IR3DUC10N AND BACKGit03tO ,

, in November 1951, primary to secondary sida leaks were discovered in the tubes o f bo th o f the Dil-1 Once Through Steam Generators (015G). there are 13,531 tubes in each OtSG. The plant design basis for a steam generator tube rupture (SCTR) accident is the double ended offset severence of a single tube. Since --

extensive cLecumferenttal cracking was discovered La approximately L200 of the 31,000 tubes , i t be came cl ear tha t a r ev ise d se t o f pro ce dur es f or dealin g wi ts both sicate and multtple SCIIs should be developed.

This report describes a program whten has been formulated to 'aprove existing procedures and operator training by providLng improved operator guidelines for dealing with tube leakage and tube rupture events. The guidelines development progran vill be described in detail, and the major revisions to the existing procedures which have been tdantLf ted as part'of the program will bs dis cuss ed. The proposed guidelines will then be presented Ln taras of their '

overall s co pe , vl th a s te p by s te p dis cuss ion o f r equ ire d o pera tor a ct ions . the analytical evaluatLons which are the bas Ls for the recosasandations, consist of a series of staulations *Leh are ongoing and will be documentad in detail in a subsequent report. The gu ide1 Lnes in th Ls TDE wer e tas te d a t the R& W s imula tor -

training cycle beginning in January,1983. the results of this training expertence are dLscussed. Flaally, the overall conclusions and adjor ,

i recommendations of the guldelit.es development program are documentel.

l -

l t

i I .

, +

I l

i

~

e e Rev. 1

• Itev. 2

/ 4 Rev. 3

.t -

TDit 405 Rev. 3 Page 15 of 81 ,

2.0 TECH'7UNCIDNS SGTR GJDE:. LIES DEVEIDIMINf PROGtM ELgure 1 shows the execution of the sensa generator tube rupture guldeline development program. The plan has three sein pathr: Fa th 1 is the development of design basis tube rupture guidelines. Path 2 ,,

is the development of multLple tube rupture guldelines; and , Fa th 3 is a benchmark effort to compare the RETRAN and REIAP 5 computar co des. This .last ef fort also includes an evaluation of the B&W AT30 analysis of a single tube rupture using MLitfRAF. The purpose of this TDR is to explain paths 1 & 2. The benchmarking and comparison efforts are discussed La a separate TDR describlng all of the tube rupture analysis work. None of the computer analys is of Path 3 has been used to justify the recommendatLons of this report. The analyses were an aLd in conceptualizing the pnysical processes during a tube rupture.

2.1, Develoament o f Des ign Bas is Ouidelines (Path 1)

The najor acttvitles ir.volved in developtag this pere of the -

guldeline were to:~ .

1. Search exLstLng industry events and procedures for lessons es he ,

learned about handling tube ruptures.

2. Define allowable steen generator stresses during cooldown (eL ther as cooldown rate or as tube / shell delta T). . .

3. Determine when OTSG's should be isolated and when they should be s teamed .

4 Eevise the miniana allcuable subcooling margia. .

5. Waive fuel in compression llet ts.

• 6. Develop'energency RCP NPSH limits. _

7. Redefine entry point conditions.

• 8. Tactor in experience from use of the guidelines on the B&W simulator.

Each of these items see JLsedssed La detail in the following sections.

2.1.1 Ltterature search Several tube rupture tasks have occurred at various operating reactors wLehin the last four years. The exper tence gained froa these events has offered us an opportunity to improve tube rupture gul delines. The asjor lessons learned from these events have been

+ Rev. L

• Rev. .!

1. 4 Rev. 3

hY 406 g'. TDR NO. REVISION NO. k N SUDGET 128006 1 01 TECHNICAL DATA REPORT ACTIVITY NO. *PAGE OF PROJECT: .ggg_3 , ' .;,_g ~b* DEPARTMENT /SECTION

" * "" "E

'~

RELEASE DATE 5 REVISION DATE 14 *4 B DOCUMENT TITLE: ,

~~

SG Tube Rupture Procedure Guidelines ORIGINATOR SIGN ATURE DATE APPROVAL (S) gTU)R DATE

<~ %e a2 2 nf 4M M- mMn

[ b '

/2.2 h l. ' '

l APPROVAL FOR EXTERNAL DISTRIBUTION DATE

. . @.k.mMn l,z i .i3 -

J Does this TDR include recommendation (s)? Eyes O No 11 yes. TFWR/TR a o' DISTR'2UTION A85 TRACT:

0 1. W. Bensel' This' document provides technical guidelines for dealing D. J. Boltz with single and multiple tube ruptures. A significant

'T. C. Broughton improvement in procedures will result from reduction of

• a M. Campagna the minimum subcooling margin and RC pump trip on' loss

• P. 1. Clark of subcooling margin, vaiver of fuel-in-compression o' J. J. Colitz limits, and revised RCP NPSE limits. Other benefits can I. 1. Tinfrock be . derived from revision of the RC pump restart criteria T. L. Gerber and from additional guidance regarding OTSG steaming and-IL. J.-Glaviano isolation. Finally, revised guidance is provided for -

• 1. W. Keaten preventing tube leak propagation. It is recommended j G. Lehmann

• that the tube-to-shell delta T be limited to 70F0 ~

D. T. Iaighton

• during tube rupture events. .

~

~ --

B. Leoiard _.

W._ V. love d Revision 2 to this TD1 included the following -

J. G. Miller

• recommendations for procedural revisions, some

• T. Moran

• of which have already been incorporated in -

EP 1202-5.

M. Nelson .

0 S. Newton * - -

o M. J. Ross

• 1. Is. olate the OTSC's on a measured or projected. . <

0 H. 3. Shipman dose race of 50 elem/hr whole body or 250 mrem /hr D. C. Slear - thyroid dose.

C. W. Smyth o M. J. Stromberg

• 2. Stop the non-ES HPI pump if the RCS is cooling *

1. J. Toole more than 100F/hr. ,

P. S. Valsh -

• Dr. R. N. Whitese:

• 3. Priorities should be spelled out in EP-1202-5:

0 1. T. Wilson a. Minimizing SCM has a priority over mini-aizing cooldown time. Og(

b. Keeping OTSC level belov 95% is less in-portant than control of the RCS cooldown -

'r P'"S*3n " 840517 rate. k f i

PDR ADOCK 05000289 -

pg L __ _ __ l P -

Dt :,0o )

Rev. 3 Page 14 of 31 1.O UICDUC .10N AND BACCCR0310 .

In November 1951, primary to secondary sida leaks were discovered in the tubes o f bo th o f the 211-1 Once Through Steam Generators (OT5G). Ihere are 13,5J1 tubes in each OISG. The plant design basis for a steam generator tube rupture (SCTR) accLdent is the double ended offse t severence of a single tube. S in ce - -

extensive circumfarentist cracking was discovered in approximately 1200 of the 31,000 tub es , L e be came cl e ar tha t a r ev ise d se t o f pro ce dur es f or dealin g wi ts both single and multtple SCIRs should be developed.

This report describes a progras *Len has been formulated to taprove existing procedures and operator training by providing improved operator guidelines for desting wLth tube leakage and tube rupture events. Iha guidelines development progran vnt be described in detail, and the major revisions to the existing procedures 41ch have been identtfled as part'of the program will bs dis cuss ed. The proposed guidelines will then be presented La taras of their

~

overall s co pe , vi ch a s te p b y s te p d is cus s ion o f r equ ire d o pera tor a c t ions . the analytical evaluattons which are the bas ts for the recoueandations, consist of a series of staulations *Leh are ongoing and will be documentad in detail in a subsequent teport. The gu idel tn es in th Le TDR ver e tas te d a t the RW s imula to r -

training cycle beginning in January,1983. The results of this training expertenes are discussed. FLnally, the overali conclusions and major recommendations of the guldelines development program are documenteJ.

d a

m.

6 se =m O

• e ,

O 4

e Rev. 1

• Rev. 2

! Rev. 3

. t TDit 405 Rev. 3 Page 15 of 81 ,

2.0 TECH'fmlCrIDNS SCIR GJDE:.,IAIS 0EVEIDIMENf PR3GLM FLgure 1 shaus the executLon of the sessa generator tube rupture guldeltne development program. The plan has three main paths: fa ch 1 is the development of design basis tube rupture guidelines. Fath 2 ,,

is the development of multtple tube rupture guldelines; and, Fath 3, is a benchasek effort to coupere the RE11M and RELAP 5 computar '

co des. This last ef fort also includes an evalua tion o f the BliJ ADO.

analysis of a single tube rupture using Mif Ef1AP. The purpos e o f this TDK is to explain paths 1 & 2. The benchmarking and comparison efforts are discussed La a separate ER describlng all of the tube rupture analysis work. None of the computer analysis of Fach 3 has j been used to justLfy the recommendatLons of this report. The analyses were an aLd in conceptualizing tha' pnysteal processes during a tube rupture.

2.1 Development o f Des ign Ras is Guidelines (Fach 1) i 4

The major activitLes involved La developing this part of the guldeline were to:"

i 1. Search extstLng Ladustry events and procedures for lessons to be ,

learned about handling tube ruptures.

l.

- 2. Define allwable steen generatse stresses charing cooldown (aLther as cooldown rate or as tubelshall delta T). . '

i

3. Dataraine when OT5C's should be isolated and when they should be s teaand .

I 4 Revise the alnimia allwable subcoolias margia. . ,

1. 5. Waive fuel La compression llatts.

I

• 6. Develop emergency RCP NPSH listes. .

7. Rede fine entry point condLtions.

• 8. Tactor in experience from use of the guide 1Laes on the B&W s taula tor.

Ea ch of thes e items Ar e .dts edss ed La de ta il in the following s ections .

2.1.1 Ltterature Search Several tube rupture leaks have occurred at varions operating reactors within the last four years. The exper tence gained froa

- these events has offered us an cpportunity to improve tube rupture l

gul delines. The ne jor lessons learned from these events haJe been l

+ Aav. 1 i

• Rev. .!

' # 4 Rev. 3

l .

p hY 406 l

J g .

TDR NO. REVISION NO. k N BUDGET 128006 1 81 TECHNICAL DATA REPORT ACTIVITY NO. 'PAGE OF ,

PRDJECT: ~ ") -

I * "" "I pgI_1, , ' ,.g e DEPARTMENT /SECTION 1~

~

RELEASE DATE 5 REVISION DATE t 4 4 9 *)

DOCUMENT TITLE: ,.

SG Tube Rupture Procedure cuidelines ORIGINATOR SIGNATURE ,

DATE APPROVALIS) gTURJE DATE

$% ~! e & t I 2. *1 - M l Wb7kWm / 2/,r/u7 5( ~

Nm '

12.7 SY l.

. . 1 1 l APPROVAI FOR EXTERNAL DISTRIBUTION DATE

. @.A.wAA '

z z .i J -

- J Does this TDRinclude recommendation (s)? Eyes CNo if yes.TFWR/TR #

'o ' DISTRIBUTION ABSTRACT:

o R. W. Bensel' This document provides technical guidelines for dealing D. J. Boltz with single and multiple tube ruptures. A significant

'T. G. 3 roughton improvement in procedures will result from reduction of o M. Campagna the miniaua subcooling margin and RC pump trip on loss o P. R. Clark of subcooling margin, vaiver of fuel-in-compression o J. J. Colitz limits, and revised RCP NPSH limits. Other benefits can I. R. Tinfrock be . derived from revision of the RC pump restart criteria T. I Gerber and from additional guidance regarding OTSG steaming and-

, L J. Glaviano isolation. Finally, revised guidance is provided for -

' 0 1. W. Keaten preventing tube leak propagation. It is recommended l

i G. Lehmann

• that the tube-to-shell delta T be limited to 70F0 ,

• during tube rupture events.

D. T.141ghton ~ '

3. I,eosard * ._

W. W. Iove d Revision 2 to this 'IDE included the following -

J. G. Miller

• recommendations for procedural revisions, some I

• T. Moran

• of which have already been incorporated in '

~

l M. Nelson

• EP 1202-5. '

o

• S. Newton - -

o M. J. Ross

• 1. Isolate the OTSG's on a measured or projected.. <

0 E. B. Shipman dose rate of 50 mrem /hr whole body or 250 mrem /hr D. C. Slear - thyroid dose.

C. W. Smyth o M. J. Stromberg

• 2. Stop the non-ES EPI pump if the RCS is cooling

• R. J. Toole more than 100T/hr. .

P. S. Walsh -

• Dr. R. N. Whitese:.* 3. Priorities should be spelled out in EP-1202-5:

• R. F. Wilson a. Minimizing SOf ha.s a priority over mini-mizing cooldown time. 0g(

- b. Keeping OTSG 1evel belov 95% is less in-l portant than control of the RCS cooldown i

9409220999 840517 rate. k i

PDR ADOCK 05000289 -

g _ _ _

. TDet 40o Rev. 3  ;

. Page 14 of gi i 1.0 mm330Cl3N AND BACKCROU}D In November 1951, primary to secondary side leaks were discovered In the tubes o f bo th o f the til-1 Once Ihrough Steam Generators (DI5G). There are 13,5J1 tubes in each OISC. The plant design basis for a staan generator tube rup:ure (SGTR) accident is the double ended offset severence of a single tube. Since --

extensive ctrcumfarential cracking was discovered in approximately L200 of the 31,000 tubes , L t be came cl ear tha t a r ev ise d se t o f pro ce dur es f or dealin g wi ta both single and multLple SGIRs should be developed.

This report describes a program whten has been formulated to *aprove exis ting procedures and operator training by providing improved operator guidelines for dealing vt th tube leakage and tube rupture events. Iha guidelines develspannt pr ogr an vill be de s cr ibed in de ta il , and the ma jo r r evis ions to th e exL s ting procedures *Ich have been identLf ted as part'of the program will bs

~

d*scussed. The proposed guidelines will then be presented La taras of their ov erall s co pe , vL ch a s te p by s te p d is cuss ion o f r equ ire d opera tor a ct ions . the analyttcal evaluations which are the bas Ls for the recousandations, consist of a s er ies o f s t aula t ion s *L eh ar e ongo in g and will be do cumen ta d in de ta il in a s ub se:;uen t r epo r t. The gu idel tn es in th is T3E v er e ta s te d a t th e B& W s imula to r -

training cycle beginning in January,1983. The results of this training

exper tenes are dtscussed. Finally, the overall conclusions and major .

recommendations of the guidelines development program are documenteJ.

• a p

• e6 1

l .

-4 e Rev. 1

• Rev. 2 4 Rev. 3

l

+ .

,g .

TDit 406 Rev. 3 Pa ge 15 of 81 I 2.0 TECH'7WCIIDNS S CTR (17DE:.UIS DEVEID PMENT PK3GRM FLgure 1 shows the execution of the s essa generator tube rupture guldeline developean,t program. The plan has three main paths: ta ch

' 1 is the development of design basis tube rupture guidelines. Fath 2 ,,

is the development of multlpte tube rupture guldelines; and. Fath 3  !

l is a benchmark effort to compare the RETRM and REIAP 5 computar es des. This last ef fort also includes an evaluation o f the B&W AEG analysis of a single tube rupture using MUITRAP. The purpose of this TDR is to eitplain pa ths 1 & 2. The benchmarking and comparison e f fo r ts ar e dt s cus s ed La a s epa rate TDR de s cr ib ing all of the tube rupture analysis work. None of the computer analysis of Fath 3 has

been used to justlfy the recommendatLons of this report. The l analyses were an aLd in conceptualizing the pnysical processes during a tube - re cura.

I 2.1 Development o f Design las is Guidelines (Fath 1)

The major acttvittes involved La developing this part of the guldeline were tor I .

1. Search extstLng Lndustry events and procedures for lessons to be ,

learned about handitag tube ruptures.

i

! 2. Define allowable stesa generator stresses bring cooldown (e Lther as cooldown rate or as tube / shell delta T). . ,

i 3. Determine when OT5C's should be isolated and when they should be s tesund .

i. .

4 Revise the minimum allcreable subesoling margla. .

1. 5. Wa tve fuel in compression llatts.

l

• 6. Develop'energency RCP NP5H 11alts. .

l 7 Bede fine entry point condleions.

• 8. Factor in experience from use of the guidelines on the B&W I stuulator.

)

Each of these itesis are ALseassed in dotatt in the follouing sections.

l 2.1.1 LL eera ture Search Several tube rupture leaks have occurred at vartons operattng reactors wLehin the last four years. The exper tence gained froa

. these events has of fered us an opportunity to taprove tube rupture

' gul delin es. The anjor lessons learned from these events have been l .

1

+ Rev. L 8 Rev. .I L . A d Rev. 3