ML18043A783

Forwards G Hart to Jm Hendrie Re Replacement of Defective Steam Generators at Surry & Jm Hendrie 790313 Response

ML18043A783
Person / Time
Site:	Palisades
Issue date:	05/17/1979
From:	Barth C NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD)
To:	Anderson G, Bechhoefer C, Livingston M AFFILIATION NOT ASSIGNED, Atomic Safety and Licensing Board Panel, WASHINGTON, UNIV. OF, SEATTLE, WA
References
790515, NUDOCS 7907090461
Download: ML18043A783 (9)

Text

/'.~~~~~~~-:-~~~~~~~~~-:--~~~~~~~~~~~------------------------

May J 5, 1979 Charles Bechhoefer, Esq., Chairman Atomic Safety and Licensing Board Panel U.s~ Nuclear Regulatory Commission Washington, D.C.

20555 Dr. George C. Anderson D~partm~nt of Oceanography Uni vers:fty of Washington Seattle:~Hashington 98195

• Gentlemen:

Dr. M. Stanley Livingston 1005 Calle Largo Santa Fe, New Me_xico 87501 In the Matter of Consumers Power Company (Palisades Nuclear Plant)

Docket No.50-255SP At the prehearing conference held in Benton Harbor on May 9, 1979, the petitioners' to intervene referred a number of times to Senator Hart's letter to Chairman Hendrie regarding replacement of steam generators.

I am enclosing Senator Hart's letter,-dated February 15, 1979 and Chairman Hendrie's response dated March 19, 1979 for the information of the Board and parties.

EnclO:~-~,res:

As Stated cc; (w/enclosures)

Atomic Safety and Licensing Board Panel Atomic Safety and Licensing Appeal Panel Michael I. Miller, Esq.

Martha E. Gibbs, Esq.

Judd L. Bacon, Esq.

Ms. Mary Sin'clair* -

Docketing arid Service Section DELO Sincerely,

~-.s-... Jr-1 i Charles A. Barth Counsel for NRC Staff DISTRIBUTION Barth.

Hoodhead Reis R.Silver D.Ziemann P.Cota R:Ba 11 a rd H.Smith D.Vassallo W.Paton FF (2)

Reg Cen: LPDR*

Shapar/Engelhardt 79070g*oltl'(. G-Chri stenbury/Sciimto

. -'"tb CAB a rth/ dkw

~

• E\\:l*Rei*s***.,,,:.4¢ ~**************~********** ***.************************ ******* ** *** * ***** ********................................................

1 -

~

.0.5J.,.,_.'?/.:Z.9..................................,.............................................................................. ********************** '

Nie lOlll( 311 (9*76) NRQ! 0249

r J0..NING9 PU.N~'-.Ptt, W. VA., CHAIRMAN Ct>MlJ1'0 s. M._"sKJC, '"1A.u;~

JltODE:"T T. 5TA1TOa..

MIKI'!: GRA~L..ALASKA HOW.A.RO H. 8..A.K[R,~N.

LLOYD BD-ITS!'.N, Tl:X.

P'ETC V. OOMD-llCI, N. MDC.

OUE'NT1H H; BUROICK. N. OAK.

JOHN H. CJ-1..t..F"f.£. R.I.

JOHN C. CUL.VER, IOWA AJ..AN K. !i=JMr'SClf-1', WYO.

I C.~."':":"!' HA.RT, COLO.

L'1\\RY P'R~5L.£R, S. DAK.

t*:*.:~*.:::.. ::*.:*: PATRIC>( MOYNIHAN, N.Y.

f I

I

--*~

JOHN W. YAGO. JR.* f:O.\\F'V DIRECTOPl

&AIL.CY GUA.FlO, MtHUrtlTY ST/..P'f" DlftECTOR Mr. Joseph M. Hendrie Chainnan

• Nuclesr Regulatory Corrnnission Washington, D. C. 20555 *

• near Chainnan Hendrie:

COMMITTEE ON ENVIRONMENT ANO PUS,i..IC WORKS WASHINGTON. D.C. 20510 February 15, 1979 I understand that the l'bclear Regulatory *commission has authorized the replacement of defective steam generators at Virginia Electric.and Power Company's Surry Nuclear Power Plant.

Further,. I understa£1d that this is the first nuclear plant repair of its type to be perfon1ed, Therefore, I would. appreciate receiving information on the nature of the problem and the repair procedure involved.

Specifically, it would be helpful if you could supply a.nsv.*ers to the following questions:

1.

How widespread is the problem of steam generator tube denting, and what are the safety implications involved?

• 2, How has NRC dealt with the problem in the past, and what future activities (and levels of effort) are planned to resolve this safety issue?

3. Please describe the NRC envirornnental and safety review procedure which led to the authorization of this repair work.

Were these reviews subject to public hearings or cormnent?

4. Please describe the steam generator replacement procedure which is being employed.

5, What environmental. and safety precautioTI.s is N"RC requiring prior to and during replacement actiyities? To what extent

~rill NRC review and monitor this effort?

6. What will be done with the defective steaJn generator parts?

What are the associated envirornnental and safety risks involved in the storage and/or disposal of these parts?

F"'~

• 1.

i F

r*

1::,

' I Joseoh M. Hendrie Page. 2

7.

. 8, Will the steam generator supplier, Westinghouse, pay for this damage repair or are the 'costs to be passed on to the V--.t.PCO constnner?

/.

I Are other nuclear power plants seheduled to undergo

. t siniilar replacement rep9,:i.:;:_~? If so, which ones,.and when?

Mr. Chairman, *this m:fonnation will be useful to the Subcorranittee on Nuclear Regulation in its ongoing oversight of cormnercial

• nuclear regulatory activities.

As the replacement procedures at Surry have

_already recently cormnenced, your timely response to these questions would be greatly appreciated.

cc: Cbrranissioner Gilinsky Commissioner Kennedy Corrnnissioner Bradford Commissioner Ahearne Sincerely,

./;iJt*

~-

Gary rt Chai an, S bcormnittee on clear egulation

~-~

c 0 p y UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 The Honorable Gary Hart, Chairman Subcommittee on Nuclear Regulation Committee on Environment and Public United States Senate Washington, D.C.

20510

Dear Mr. Chairman:

March 19, 1979

~ "\\""*

Works.

~ "'

I *'

Your letter, dated February 15, 1979, requested information concerning repair of the steam generators at Virginia Electric and Power Company's Surry Power Station.

Our response to your specific questions is provided as *Enclosure 1.

The steam/generator repair program for Surry Unit No. l and Unit No. 2 was granted NRG approval by license amendments dated January 19, 1979 and supported by an Environmental Impact Appraisal (EIA) and a. Safety Evaluation Report (SER).

Copies of the licens~ amendments, the Notice of Issuance, the EIA and SER are also enclosed.

In order to further assist you in understanding the phenomenon of tube denting, I am also enclosing a copy of a report which has just been completed entitled, "Summary of Operating Experience with Recirculating Steam Generators, NUREG-0523, 11 dated January, 1979.

In a note of interest to your staff, the Commission has requested a staff briefing on the issues of denting, steam generator repairs and associated legal questions.

The briefing has been scheduled for Thursday, March 29, 1979 at 2:30 p.m. at the Commissioners Conference Room.

The briefing is open to the public.

Enclosures:

1.

Answers to Questions 2.. Ltr to VEPCO fm NRC w/Encls dtd 1 /20/79

3.

Ltr to VEPCO fm NRG w/Encl dtd 12/15/78

. 4.

NUREG-0523 Sincerely, Joseph M. Hendrie

5.

Ltr fm Allen, NAEC to Commissioners dtd 12/29/78

6.

Ltr fm Denton, NRR to Allen, NAEC dtd 2/1/79 cc:

Sen. Alan Simpson

1.

t.m.. LU.":>UK.t.

I e

AHSWERS TO QUESTIONS IN FEBRUARY 20, 1979 LETTER FROM SEHATOR GARY HART, CHAIRMAN, SUBCOKMITTE~ ON NUCLEAR REGULATION

/

How widespread is the problem of stea~ generator tube d1n,ting, and what are the safety implications involved?-...---..

Answer:

Denting as a fonn of steahi.,.genera tor tube degradation has only been observed in recirculating (U-tube} type steam generators designed and manufactu~ed by Westinghouse

{\\./) and Combustion Engineering (CE).

As of December*

1978, there ~ere 33 plants in the United States with

'this type of steam generator.

Sixteen of these (12 W and 4 CE) have suffered some tube denting.

A *recently pub 1 i shed report (NUREG-0523) summarizes various operating problems, including tube denting, associated with domestic operating P~R's.

As indicated in Table 1 of NUREG-0523, Surry Un its 1 and 2, Turkey Point Units 3 and 4 and San Onofre Unit 1 have exprienced the ~ost extensive tube denting.

The safety implications associated with the denting phenomenon relate to potential radioactive releases during normal and accident conditions since denting can lead to tube cracking and leaking. Hinor leaks have occurred in steam generators which have severe tiibe denting, resulting in contamination* of the-secondary sysU:m and in*

small radioactive releases to the environment.

Experience has shown that the leaks caused by tube denting have genera11y been small and are quick1y detected, pennitting orderly reactor shutdown.

lf 1 eakage through cracked steam genera tor tubes were to increase substantia11y concurrent with a postulated accident, e.g., a main steam line break* (MSLB) or a loss of coolant accident (LOCA), both the severity of those accidents and their ~ose consequences woul~ be increased.

Therefore, it is very important to maintain a high degree of assurance that there will be no substantial increase in tube leakage due to accident conditions.

This assurance is achieved by imposition of the licensing condition dfscussed in the response to Question 2.

. '*~..

-*~:**.

2.

i*

(::-.. ::::::

t*:::::::

e..

• How has NRC dealt with the problem in the past, and what future activities (and levels of effort) are planned to resolve this safety f ssue?

./

, /*

I..

An.swer:

In addition to approving ~he r-e-placement of the Surry steam genera tors with \\ol\\l'es designed to minimize the potential for tube d~nting, the NRC has also taken

.several steps to identify plants that develop denting-and to be a~sured that this denting does not become an actual safety problem.

For plants now operating with severely degraded steam generator tubes, NRC has imposed additional licensing conditions that require (1) augrnent~d steam.

generator ~ube inservice inspections (i.e., increased

• inspection frequency and expanded inspection sample), (2) preventive tube plugging, and (3) more stringent Technical Specification limits on the allowable reactor coolant leakage rate during normal operation.

In the most *severely dented steam generators, all tub~s in the innermost two' rows have been plugged even though most of them have not leaked.

This action has eliminated the potential for the occurrence -0f large, fast developing.

leaks at the top of the LI-bend region which is con~idered most vulnerable to cracking.

For detailed discussions *on other plant specific remedial actions that have been required. by *NRG, NUREG-0523, Section 4 provide_s typical preventive tube plugging criteria that must* have been implemented.

The stringent 1 eakage rate 1 imit. imposed by*

• NRC was chosen to detect 1 ea ks from cracks that are very small.

Early detectibn and plugging are a means to.

prevent a crack from propagating and weakening the tube.. -

• -such that it could suddenly rupture during postulated**.

accidents.

With regard to further resolution of this safety issue,.

the NRC staff has fonnulated Task Action Plans (TAPs) A-3 and A-4 for the Generic Technical Activiti.es which address Westinghouse and ~ombustion Engineering *steam generator tube *integrity (.Appendix B of NUREG-0523).

Results from NRC and industry research efforts will pro vi de *addi tiona 1 bases for confirming or revising current tube r:epair or plugging criteria.

For new designs, specific features.

are being incorporated to minimize the potential for tube denting.

These generic tasks have been given high priority by NRC and wi11 require.. approximately six man years of staff effort. Completion of these tasks is scheduled for FY* 1980.

f ~

J

~

I

~.

t*:.:-::::

t

., 3.

Please describe the NRC environmental and safety review procedure which led to the authorization of this repair.work.

Were these reviews subject to public hearings or c9ITTTient?

Answer:

I Fo11owing receipt of VEP,.:CO,'s l_e_-tter dated August 17, 1977' which transmi tte,d the report entitled 11Steam Generator Repair Program; Surry Power Sta ti on, Unit Nos.

1 and 2 11

, the staff detenni ned that the proposed program required its review, approval and issuance of license amendments~ A Federal Register Notice of Proposed Issuance was published on October 27, 1977 (42 Fed. Reg. 56652).

The staff's environmental review included an appraisal of occupational radiation exposure, public radiation exposure, accidents, cost, land use, noise,

• traffic and materials. Various alternatives to the repair effort (such as plant shutdown) were evaluated.

The staff's safety review included steam generator design changes, effects of repair activities, transient and accident.analyses, radiological considerations and security.

The resu1ts of the staff reyiew are presented*.

in the Environmental Impact Appraisal (EIA) and a Safety Eva 1 ua tion Report (SER).

A Federal Register Notice of-Proposed Issuance publish~d October 27, 1977, provided for a request for hearing within 30 days of publication of the notice.

No request

• for *a hearing was received.

However, -in response to that notice, the Cormionwea1th of Virginia requested that it be.

allowed until 10 days after the issuance of the staff SER to decide whether it would request a hearing.

The Commonwealth 1s request was granted.

The Corrrnonwealth stated, following issuance of the SER, that it wou111not request a hearing in the proposed licensing action.-

Jj On February l ~ 1979 a Oecemb.er 29, 1978 request for hearing on this matter under 10 CFR 2.206 of the Corrmission's Regulations from Hs.

June Allen, on behalf of the North Anna Environmental Coalition, was denied by the Director of the Office of N~clear Reactor Regulation.

A copy of that decision is enclosed for your infomation.

In accordance with the Car.mission's rules, the Corrrnission is presently considering whether or not to take review of the Oirector 1 s denial.

i "

r.

(:~:':':':":>

i

(~~(:~

4.

I -

't Please describe the steam generator replacement procedure which is being employed.

Response: Briefly, the procedure consists of defueling the reactor, draining the reactor codl~nt leaps, cutting ~ach steam generator from its rea,.c~pr coolant loop and secondary system, removing the tbp' portion from the steam generator lower assembly including the shell and tube bundle.

A new lower assembly will be installed for each removed lower assembly.

The old lower assemblies will be* stored in a specially designed faci1ity.

Further details are provided in the SER.

5.

What environmental and safety precautions is -NRC requ1r1ng prior to and during replacement activities? To what extent will NRC review and monitor this effort?

Answer:

The Surry Power Sta ti on Unit Nos. 1 and 2 1 i censes have been amended to incorporate several requirements to be met during the repair program.

Among these are that.

all fuel will be removed from the reactor pressure vessel and stored in the spent fuel pool and temporary containment and ventilation areas will be established for.cutting and grinding operations.

The EIA and SER describe additional -

environmental and safety precautions to which VEPCO is corranitted.

The repair activities will be inspected and monitored by the NRC Office of Inspection and Enforcement.

In addition to the resident inspector assigned to the Surry site, approximately eight additional inspectors have been assigned to follow this repair effort on a part-time basis.

This additional effort will be equivalent to approximately four full-time inspectors.

6.

What will be done with the defective steam generator parts? What are the associated environmental and safety risks involved in the

. storage and/or disposal of these parts?

Answer:

The removed steam generator parts will be sealed and stored on site in a separate shielded facility constructed for this purpose until the Surry.reactors are decommissioned.

A detailed account of this disposal along with the associated risks is presented in the SER and EIA.

Briefly; the risks are those of exposure.to the residual radioactive materials in the sealed parts.

Because of the sealing, shielding and periodic monitoring for any airborne or liquid pathway releases from this special storage facility, the risks are considered minimal and not environmentally significant.

~

,)...

\\-_*:::::.~

' \\.

5 -

/<

7.

~ill the stea~ generator supplier, We~tinghouse, pay. for this aa:::age repair or are the costs tp/be p~sed on the VEPC_O consur:ier-?

~

I Answer:

It is our understandJng"'that the costs for the repair will not be paid by ~estinghouse. The total costs for the repair will consist of the costs for the repair effort itself (materials and labor) plus the differential fuel costs that will be experienced while the nuclear plants are down for the repair.

We understand that the repair effort itself is being handled by VEPCO as an improvement and will be financed mainly but not entirely through stocks, bonds and other financial mechanisms.

We understand that pa~t of the ~epair effort itself and all of the differential fuel costs will be passed on to the YEPCO consumer.

8.

Are other nuclear* power plants scheduled to undergo simil~r replacement repairs? If so, which ones, and when?

Answer:

The Florida Power and Light Company has requested.

HRC approva 1 of similar repairs for its Turkey Point Nuclear Plant Unit Nos. 3 and 4 *. The NRC review, similar to that perfonned for. the repair program at the Surry Station,. is almost complete~ The Turkey Point repairs are 1 i ke ly to fo 11 ow the Surry repairs by at 1 east.

one year.

Consul'ilers Power Company is considering rep 1 acement of the steam generators in its Palisades Plant, although at this time it is not definite that it will decide that it is necessary to do so. Although over 20 percent of its steam generator tubes have been plugged, it has experienced only minor tube denting problems.

The major cause of pluggin~ has been the phenomenon of tube wastage, a problem that has generally been arrested.

We are not aware of any of the other 16 plants considering similar repairs in the near future.

iube plugging required to date (see Table 2 of NUREG 0523) at these plants has been considerably less than at the Surry and Turkey Point Plants, indicating that the i~pact on plant operation has a]so been much lower.

,