ML20035F625

Responds to Util Requesting NRC Review of TS Criteria by Which SG Tubes Would Be Repaired.Proposes That Meeting Be Held on 930510 in Rockville,Md to Discuss Schedules for Planning of Upcoming Outage

ML20035F625
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	04/19/1993
From:	Varga S Office of Nuclear Reactor Regulation
To:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO.
References
TAC-M85675, NUDOCS 9304220101
Download: ML20035F625 (6)

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< f" April 19, 1993 Docket No. 50-213 Mr. John F. Opeka Executive Vice President, Nuclear Connecticut Yankee Atomic Power Company Northeast Nuclear Energy Company Post Office Box 270 Hartford, Connecticut 06141-0270

Dear Mr. Opeka:

SIJBJECT:

HADDAM NECK PLANT - MANAGEMEIP. OF STEAM GENERATOR TUBE FtAWS (TAC NO. #M85575)

By letter dated April 1, 1993, Connecticut Yankee Atomic Power Company (CYAPCO) requested the NRC to review its proposed Technical Specification (TS) criteri; by which steam generator tubes would be repaired. CYAPC0 has proposed Doth alternate and interim steam generator plugging criteria. CYAPC0 requested that the TS changes be approved by April 30, 1993, in supp>t of its outage scheduled to start on May 15, 1993. We recognize that your criteria for allowing defects in the tubes, withir the tubesheet region, is based on crack length and is different from the other currently prooosed voltage based alternate plugging criteria (APC) and interim (IPC) submi;tals. The staff will not be reviewing your initial APC submittal until the generic APC review is completed. However, the staff has begun review of your IPC submittal which you propose to implement for the next operating cycle.

We are obtaining technical assistance from Pacific Northwest Laboratory (PNL) regarding the leakage model and reliability of your eddy-current inspections.

PNL is assisting the staff in the review of the generic APC work. We believe 1

PNL's expertise t.nd experience with these reviews are necessary to assure a timely review.

However, PNL will not be available until May 1,1993, to start the review. Thercfore, we propose tc make a decision concerning your request by May 15, 1993.

We propose thu. a meeting be held at NRC, One White Flint North, Rockville, Maryland on May 10, 1993, to discuss your schedules for the planning of the upcoming outage, the extent of the staff's current review support, and follow-up on discussions held with you and the NRC staff on April 7, 1993.

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. interim, we will be holding conference calls with you to discuss the calculation of the maximum faulted load and the related dose calculations, who:;e reviews have started.

If you have any questions please contact Alan Wang at (301) 504-1445.

Sincerely, Original signed by Steven A. Varga, Director Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc:

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w Mr. John F. Opeka interim, we will be holding conference calls with you to discuss the calculation of the maximum faulted load and the related dose calculations, tvhose reviews have started-If you have any questions please contact Alan Wang at (301) 504-1445.

Sincerely, h'

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Division of Reactor Proje s - I/II Office of Nuclear Reactor egulation cc:

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-Mr. John F. Opeka l

Connecticut-Yankee-Atomic-Power Company Haddam Neck P1 ant l

cc:

Gerald Garfield, Esquire R. M. Kacich, Director i

Day, Berry and Howard Nuclear Licensing Counselors at Law Northeast Utilities Service Company-j City Place Post Office Box 270 i

Hartford, Connecticut 06103-3499 Hartford, Connecticut 06141-0270 j

W. D. Romberg, Vice President S. E. Scace, Vice President a

Nuclear Operations Services Millstone Nuclear Power Station Northeast Utilities Service Company Northeast Nuclear Energy Company

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Post Office Box 270 Post Office Box 128 1

Hartford, Connecticut 06141-0270 Waterford, Connecticut 06385 I

Kevin McCarthy, Director.

Regional Administrator 3

Radiation Control Unit Region I Department of Environmental Protection U.S. Nuclear Regulatory Commission State Office Building 475 Allendale Road Hartford, Connecticut 06106 King of Prussia, Pennsylvania,19406'.

Allan Johanson,_ Assistant. Director Board of Selectmen 1

Office of Policy and Management Town Office Building l

Policy Development and Planning Division Haddam Connecticut 06438 1

t 80 Washington Street j

Hartford, Connecticut 06106 Resident Inspector j

Haddam Neck Plant j

J. P. Stetz, Vice President-c/o U.S. Nuclear Regulatory Commission -

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~ Haddam Neck Plant 361 Injun Hollow Road l

Connecticut Yankee Atomic Power Company East Hampton, Connecticut-06424-3099:

j 362'Injun Hollow Road East Hampton, Connecticut-06424-3099 Nicholas S. Reynolds Winston & Strawn i

D. J. Ray 1400.L Street, NW Haddam Neck Unit Director Washington, DC 20005-3502 Connecticut Yankee Atomic Power Company 362 Injun Hollow Road j

East _Hampton, Connecticut 06424-3099 G. H. Bouchard, Director Nuclear Quality Services Northeast Utilities Service Company Post Office Box 270 j

Hartford, Connecticut 06141-0270 7

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If the due date does not allow adequete t2me to respond.to this t 2 c L. e t, you may request a revi sed due date.

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Washington, DC 20555 Gentlemen:

Haddam Neck Plant tji na ement of ShGmerator Tube Flaws Lg e area of two proposed license amendments thatThe purpose o on in the-safe and economical operation of the Haddam Neck Plant.are critical to the continued Atomic Power Company (CYAPCO has submitted to' the NRC Staff proposed Connecticut. Yankee-revisions to the -technical spe)cification. criterion by which steam tubes at the Haddam Neck' Plant would be repaired.

. generator philosophy This proposal is similar:in to, but significantly different in, submitted 'recently by other pressurized wato application i from proposals based on generic industry " alternate repair criterion (ARC)" effort ireacto industry generic " ARC proposals" are focused on 'outside diamete s

The corrosion cracking l(ODSCC) that occurs at the top of the steam gen above the tubesheet.tubesheet, the first tube support plate, or other locations The. Haddam Neck Plant has partial-depth ro e SG tube Haddam Neck Plant.

The cracks in tubes that we are proposing to retain in service are loca the roll expansion regicn, ~ which is. defined e

n tube,. apprcximately 18 inches from'the secondary side of the tube has the bot Hoddam Neck initiated on the inside diameter of the tubesPlant SG tube fla s eet.

The flaws are small stress expansion-re(gion.i.e., : inside diameter corrosion cracking) in the ' role to. a isteam generator tube rupture due to flaws in th

.This ~is' very-proposal only applies to flaws in this specific location (i.e.r 18 inches do n CYAPCD's inside the tubesheet).

- fact that due to the SG de' sign, the constraint of the mass w

. addressed by our proposal:are actually' rupture resistant.

It must be. emphasized that CYAPCO's -strategy for continued safe an operation of the Haddam Neck Plant-_is based on retaining the o~riginal 5G service. for the remainder of licensed plant life.

' Current ' preli~ inary.

econ'omic ' evaluations: of the Haddam Neck Plar.t effectively. preclude m

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replacement.

As such, avoiding unnecessary tube plugging is imperative ensure continued operation of the Haddam Neck Plant until the end of to life.

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Recently, our proposed license amendmentthe NRC Staff verbally informed CYAPC0 th:

requests is not of NRC Staff resources to other related generic issues. imminent due to the diversion Staff management redirect a portion of knowledgeable Staff resources to We request that NRC CYAPCO's pending applications.

j The following is the basis of our request.

On July 31, t

for the Haddam Neck Plant to authorize the eliminatio of steam generator tubes in the tubesheet expansion zone (E2) roll transit ugging This revised criterion will allow certain tubes, with axial cracks of a area.

well-characterized nature in the tube sheet CZ roll transition area caused by primary water stress corrosion cracking (PWSCC), to remain in which are service.

CYAPCO r.rovided a detailed presentation to the NRC Staff on our proposal i meeting on October 22, 1992.

na NRC' Staff, CYAPC0 elected to submit a second license amendm NRC Staff.

CYAPC0 believed this was responsive to the stated NRC concerns and e

served as a less desirable but acceptable interim arrangement until our July 31, 1992, a January 29, 1993, plication was approved.

The second proposes a significantly reduced limitapplication, dated SG tube leakage on post-accident and uses more realistic steam generator differential pressures. CYAPC0 considers both amendment requests submitted to the NRC Staff to be v al i d, with the January 29, 1993, application presenting alternative until our July 31, 1992, letter is approved by the NRC.

i an interim The issuance of these amendments is significant to the continued operation the Haddam Neck Plant.

Long-term, continued plant operation is contingent I

upon having available safe and approved approaches to address..g PWSCC flaw which do not require SG plugging.

Without such, the Haddam Neck Plant will of significant resources.likely be forced to plug many additional tubes, resulting exposure that would be experienced to plug the additionalThese expenditu associated with calculating tubes, the costs new tube plugging limits and eventually the potential loss of megawatts from the derating of the plant due to the tube i

(1)

J.

F.

Opeka letter to U.S.

Nuclear Regulatory Commission, " Proposed Revision to lechnical dated July 31. 1992.

Specifications-Steam Generator Repair Criteria,"

(2)

J. f. Opeka letter to the U.S Regulatory Commission, to Technical Specifications Steam Generator Repair Criteria," dated

" Proposed Revision January 29, 1993.

_,mameow.

APR.2-93 ERI 10:02 Ge n. Facil. Licensing FAX NO. 203 665 5896 P.04 d.S. Nuclear Regulatory Commission B14297/Page 3 April 1, 1993 plugging.

We believe this is public health and safety.

unnecessary to ensure continued p tection of' If the proposed CYAPCO criterion is approved for the Haddam CYAPCC, during the upcoming outage, (best estimate) and 250 (upper estimate) tubes which will be able tcouid r service.

This corresponds to a dose savings of between o remain in respectively.

We anticipate that additional savings could be recognized 10 and 25 Man-Rem during subsequent outages.

The CYAPCO applications of July 31, 1992, and January 29 1993, are unique when compared to other submittals made by other licensees o,n thi should be considered on their own merits, s subject and with respect to this particular issue, lhe Haddam Neck Plant SGs' design, other situations under review ~by the NRC Staff.is inherently safer when compared to cracks in tubes that we are proposing to retain in service are located in roll expansion region, which is defined as the bottom 5 inches of the t approximately 18 inches from the secondary side of the tubesheet.

The u e, tubesheet completely surrounds the tube in the region where the cracks located.

Depending on the length of the axial crack assumed to be present are the tube can either withstand a pressure load of three times the normal cpehting pressure on its own, or will expand and come in contact with th tubesheet prior to reaching the pressure which would crack were in the free span of the tube.

cause a burst if the regardless of the length of the axial Thus, burst of the tube is precluded crack assumed region when the proposed CYAPCO criterion is applicable. to be present in the The method by which CYADC0 will identify which tubes will require repai more conservative than what the industry has identified as acceptable s

will utilize the bobbin coil, as well as rotating pancake coil or more CYAPC0 advanced NDE techniques, to detect and characterize flaws.

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The Haddam Neck Plant is also unique in its design when compared to the applicants in an additional important respect, Haddam Neck has loop isolatio l

er i

valves.

The loop isolation valves could be utilized as' part excessive primary to secondary leakage. accident mitigation strateg i

of the severe Finally, with regard to off-site doses, CYAPC0 would also like to note that order to approach 10CFR100 limits, all of the 1

4 Standard Review Plan (SRP) assumptions must exist simultaneously.

To incur simultaneous with 95 percent meteorology, high coolant activity, maximum a main steam line break secondary leakage has a combined probability of less than CYAPC0 is 4

required to use SRP assumptions per year.

If calculation in support of the proposed CYAPCO criterion,in the off site dose assessm January 29,-1993

letter, as was done in our rate and, consequ, ently, this will significantly reduce the allowable leak ~

q the number of degraded tubes which could be left in

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1 U.S. Nuclear Regulatory Commission B14?')7/P:ge 4 April 1, 1993 service.

This would reduce the benefit of the proposal without appreciable safety benefit.

any realistically manage cracksIn conclusion, application of the revised crite w CYAPCO to rnore dose consequences to plant workers in the unnecessary repairin ste of tubes.

We are providing this information issue facing the Haddam Neck Plant.to NRC Staff inanagement to advise of significant CYAPCO's applications dated Julythis letter is more detailed inform a

31, 1992, and January 29, 1993 To suppo.rt n reviewing CYAPC0 is seeking a Staff decision not later than Frid May 15, 1993,

, April 30, 1993.

Lastly, we wish to commend requirements marginal to safety.the NRC Staff for its initiative to eliminate We believe this amendment request represents an opportunity for the NRC Staff to put this philosophical intent into practice.

Very truly yours, CONNECTICUT YANKEE ATOMIC-POWER COMP h

M l-M J. F. Opeka; I

Executive Vice President

1. T. Martin, Region I Administrator cc:

W. Minners, Director, Division of Safety issue Resolution J. G. Partlow, Associate Director for Projects 1. E. Murley W. J. Raymond, Senior Resident inspector, Haddam Neck Plant W.'T. Russell Associate Diractor for Inspection andJ. E. R Technical Assessment J. H. Sniezek, Deputy Executive Director for Nuclear Reactor Regulation Regional Operations and Research A. B. Wang, NRC Project Manager, Haddam Neck Plant t

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• F M. NO. 203 665 5896 P. 07 U.S. Nuclear Regulatory Comission B14397/ Attachment 1/Page 1 April 1, 1993 Haddam Neck Plant Mnacement of Steam Ganeratordbe riaws n

Intredm non On July 31, for the Haddam Neck Plant to authorize the elimination o of steam generator tubes in the tubesheet expansion zone (EZ) roll nse necessary plugging area.

This proposed CYAPC0 criterion will ransition cracks of a well-characterized nature in the tube sheetallow certain tubes, with axi area which are caused by primary water stress corrosion cracking (PW EZ roll transition remain in service.

to the NRC Staff,CYAPCO's safety assessment, which was sub

), to amendment request listed the assumptions used to support this proposal.

meeting on October 22,CYAPC0 provided a detailed presentation to t 1992.

roposal in a certain assumptions proposed in the radiological assessmentPreviously acceptable to the NRC Staff.

CYAPC0 believes that the verbally stated area may not be.

posi, tion of the NRC Staff to apply the current day licensing c it plant which is licensed to different criteria has not been technic r eria to a justified.

with the planning required for the upcoming refueling ou

, and C'tAPCO elected to submit a second license amendment request t or Haddam Neck, CYAPCO believed this was responsive to the stated NRC concerns a d less desirable but application was approved. acceptable interim arrangement n served as a until our July 31, 1992 The second application, dated January is responsive to the NRC Staff's radiological dose consequence calcu using the Standard Review Plan (SRP) a ons The second application based upon the proposed CYAPC0 criterion ccriteri our July 31, 1992, letter,

. ontained in pressures. CYAPCO considers both amendment requests submitt

valid, with the January 29,

1993, application presenting an interim o be alternative until our July 31, 1992, letter is approved by the NRC The issuance of this amendment is significant to the continued ope the Haddam Neck Plant.

Long-term, ration of which do not require SG plugging.u;)on having available safe and Without such, Haddam Neck will likely be aws forced to plug many additional

tubes, resulting in the expenditure of (1)

J.

F.

Opeka letter to U.S.

Nuclear Regulatory Commission, " Proposed Revision to Techr.ical Specifications-Steam Generator dated July 31, 1992.

Repair Criteria,"

(2)

J. f. Opeka letter to the U.S Regulatory Commission, to Technical Specifications

" Proposed Revision January 29, 1993.

- Steam Generator Repair Criteria," dated.

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t U.S. Nuclear Regulatory Commission B14397/ Attachment }/Page 2 April },

1993 significant resources.

These expenditures include the additional man exposure that would be experienced to plug the additional associated with calculating rem tubes,'the costs new tube plugging limits and potential loss of megawatts due to the potential derating the tube plugging, which we believe is of the plant due to t

eventually the-protection of public health and safety.

unneces sary to ensure continued If the proposed CYAPCO criterion

CYAPCO, is approved for the Hadda.n Neck during the upcoming outage, could (best estimate) and 250 (upper estimate) tubes which will brealize a savin service.

This corresponds to a dose savings of between 10 and 2 100 e able to remair in respectively.

We anticipate t.h a t additional savings could be duririg subsequent outages.

recognized To date, CYAPC0 has not been led to believe that pending amendment applications is imminent.

issuance of either of the documenting from our perspective why the assumptions co t i Therefore, CYAPCO is hereby amendment requests are licensing basis of the Haddam Neck Plant.both technically defensible and con with the Staff review of the CYAPC0 proposals.

This letter ' seeks to assist NRC appropriate planning can be completed for the outage commePrompt attent

1993, ncing in mid-May lia$iam._Nec k C]}_P_CO2hhrPlant's tiniouenemf__0ni.grL andDlicat ign n

of the Propos _ed The CYAPC0 applications of July 31, when compared to submittals made by other and January 29, 1993, are unique

1992, Haddam Neck Plant steam generators' design, with respect to thi licensees on this subject.

The issue, is inherently safer when compared to other situati s particular the NRC Staff.

At the Haddam Neck Plant, ons under review by proposing to retain in service are located in the roll expansionthe tubes with is defined as the bottom 5 inches of the tube region, which the secondary side of the tube sheet approximately ' - inches from allowable crack length and circumferen(tialfigure 1).

The criterion defines an integrity

_i of the tube is extent such that the structural assured -during normal operation and postulated accident conditions as specified in Regulato y Guide 1.121 proposed allowable length and circumferential extent is the HaddThe basis for e

specific application of a generic alternate repair criterion d am Neck Plant committee of industry experts under the direction of the Electric Pow eveloped by a Research Institute.

One important assumption of ti t besh et an the crac s to f the t r ter on Ha da ec ts steam generator tubes 1

e en conservative since the st generator tubes are onl through the tubesheet Th dSarti11l t5e"\\

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three times the norinal operating pressure on its own i

in contact with the tubesheet prior to reaching the pressure, or will expand a burst if the crack were in the free span of the tube which would cause tube is precluded regardless of the length of the axialThus, burst of the present in the region when the proposed CYAPC0 criterion is ap crack assumed to be Additional failure modes were also analyzed tracks which meet the proposed criterion will, and it was found that tubes with exhibit acceptable conditions with the appropriate margins of safety. levels of leakagi and postulated accident The method by which CYAPC0 will identify which tubes will will utilize the bobbin coil, as well as rotating pancakemo require repair is a

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CYAPC0 d

acterize flaws.

The bobbin coil method will be performed on the totalcoil, t

.gth of all the

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steam generator tubes.

The rotating pancake coil examination is anticipated to be performed in the expanded roll area stean generator tubes.

This examination area is considered conservati of all the Haddam Neck Plant t

has not er crienced any deep tube sheet crevice corrosion, as other plants have.

NDE techniques and will perform future r aminations using thCYAPCO test methods.

e most appropriate pancake coil methodologies.CYAP,CO has also reviewed the support p using rotating intergranular attack or outside diameter stress corrosion cra kino cra any anticipated to be found in the future.

c ng, nor are however, continue to be sampled to verify that no cracking existThe sup found tube denting in the support plate region in two of our four_ s s.

CYAPC0 has generators.

during future outages to verify no cracking is presentThis dentin t

The Haddam Neck Plant is also unique in its design when compar d t applicants which wish to use the alternate repair criterion in an e

o the other important respect.

valves could be utilized as part of the severe accident mitig The loop isolation additional for any steam generator which may be rategy 3econdary leakage.

experiencing excessive. primary to they be maintained within the MOV qualification programThe va were utilized and did function they could reduce any off-site doses th However, if they otherwise occur.

at may-Dose Assessment-CYAPCO's proposed use of the steam generator proposed CYAPCO criterion justified based on a combination of enhanced in-service inspection i

is limit bzsed on crack length as well as crack depth, and a limit on th

, a repair of tubes with characterized cracks retained in service.

e number augmented inspections and an acceptable crack length-based repair li The combination of provides an ' alternative to the current 50 percent depth-based repair e_-

pp-2-93 RI 10 05 Gen. Fac i l. Lic"S m-cAJ NO. 203 665 5896 P.10 U.S. Nuclear Regulatory Commission B14397/ Attachment 1/Page 4 April 1, 1993 Neck Plant steam generators which have experienced evaluation of the off site doses resulting from imple

~ e Haddam rmed, including the generatcr tube proposed CYAPC0 criterion.

The assumptions used in the entation of the steam calculation of the off-site doses found in our July 31 been embraced by the Staff, and this is one motivation f, 1992, letter have no this letter.

or CYAPCO in docketing i

A main steam line break radiolo with NRC NUREG 0800 SRP criteria,gicalconsequence evaluation, in accordance the Haddam Neck Plant.

In the 1980s,' is beyond the current licensing basis for I

steam line break using SRP assumptions. Program (SEP), the se assessment for the plant was acceptably safe this SEP ef fort verified plantWhile the NRC Staff conclud explicitly impose new requ,irements on the Haddam Neck Plantsafety and d safety significance of the proposed amendment.

To evaluate the using most of the SRP criteria, with CYAPC0 performed an analysis justified.

sole exceptions were that CYAPC0 assumed a post-a The leakage rate of 100 gpm versus the 1 gpm in the SRP versus 500 in the SRP, and included an iodine decontamination fa t the, steam

, a spiking factor of 100 generators.

The spiking factor of 500 has been shown to be c or of 10 in excessively conservative by at least a factor of 15

• data for Haddam Neck show a spiking factor of approximately 25 factual trip and depressurization.

We have conservatively used a or a reactor this calculation.

The i

Any leakage would have to traverse 18 inch leakage location.

annulus between the tube and tubesheet, past all the tubes in additi steam dryers.

Significant plateout can be expected.

on to the CYAPC0 believes that these modifications to the SRP criteria and technically justified.

The relaxation in some criteria is more than e conservative compensated by the sinnificant including:

conservatism in the other SRP assur tions, e

1.

A 95 percent worst-case higher than typical meteorology, meteorology-approximately 10-100 times t

this where thermal plume rise can be expected.especially for a release such as (3)

U.S. Nuclear Regulatory Commission, "NUREG-0800, Standard Revi the Review of Safety Analysis Reports for Nuclear Plants "

ew Plan for as amended.

(4)

P. Adams and C. L. Atwood, EG&G, Idaho, Nucl 3

upture, J.

1991.

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2.

The plant is assumed to operate at its technical primary coolant limit of 1 pCi/gm DEQ 1 131 t

specification 10-1000 times less than this, Typical operation is 3.

The plant is assumed to operate at its secondary side te specification limit of 0.1 C/gm I-131.

This more than a factor of 1000 and should not even be con idis conservativei dose calculation, as the contribution will be small comp s ered in the primary activity released.

ared to the Initial secondary side activity accounts for 60 percent of the dose in the SEP NRC evaluation of this accident.

4 The plant is assumed to operate at its primary to seco technical specification leak rate limit.

. Typically, the plant operates at 10 1000 times less than this limit.

5.

tubes allowed by the 100 gpm limit and all thThe pl!

egraded conservatively calculated leak rate.

e tubes leak at their times less than this.

Expected leakage would be 100 Hence, the conservatisms in the steam line break dose offset the proposed allowable increased leak rate of 100 gpmcalcula CYAPCO would also like to note that in order to approach 10CFR10 of the $RP assumptions must exist simultaneously.

0 limits, all break simultaneous with 95 percent meteorology To incur a main steam line iodine spiking, minimum iodine decontamination facto, high coolant activity, max secondary leakage has a combined probability of less than 10* per, CYAPCO is forced to use SRP assumptions in r year,

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calculation in support of the proposed CYAPC0 criterionthe off-site dose January 29, 1993

letter, assessment the number of degraded tubes which coul as was done in our rate and, consequ,ently, service.

This would reduce the benefit of the proposal without any i

in appreciable safety benefit.

Severe Accident Considerations Subsequent to the October 22, 1992, meeting, CYAPC0 criterion letter.that severe accident consideration i

ressed in our proposed CYAPCO does not believe that consideration of s license amendment request results in because the the need for design of the Haddam Neck Plant any further conservatism critical way, from other licensees that have made similar applicati differs significantly, in a NRC Staff.

The Haddam Neck Plant ons to the j

is designed with partial depth roll steam generator tubes.

Therefore, the tubes with axial cracks proposed for r

Fa..t.

Licensiae cAX tio. 203 665 5896 P I2'-

3 APR 2-93 ERI 10:07-Gen.

ct U.S. Nuclear Regulatory Commission B14397/ Attachment 1/Page 6 April 1, 1993 retaining in-service are 18 inches down t egins to open under high differential presinside the tubesheet.

1 A crack that tubesheet.

.On a qualitative basis, one would expect a portion of a the tubesheet to burst under severe accident location within the tubesheet.

conditions before a failure occurring in the tube., we propose to leave in seThere is no chan cracked' other tubes remaining in service rvice compared to the 1

design, consideration of severe acc.

There fore, for the Haddam Neck Plant modification to the pending proposal,idents does not result in the need for any Durhsion i

Application of the proposed CYAPC0 criterion will allow C realistically manage cracks in steam generaw tubes and avoid radiological dose consecuences to plant workers in the CYAPC0 currently meets unnecessary repair of tubes, application of currently applicable repair criter represents a new i

believe that application of the current We address severe accidents is not warranted. SRP criteria or further steps to We are providing and January 29,this information to assist the Staff in the review July 31, 1992, 1993, license amendment for%ard to prompt and favorable treatment of our pendi our requests.

We look r

ng applications.

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