ML20236H083

Responds to Re Possibility of LOCA at Plants. Majority of LOCA Research Complete & Understanding of ECCS Performance During LOCA Greatly Improved.Conservatism of Methods Specified in Commission Rules Demonstrated

ML20236H083
Person / Time
Site:	Pilgrim, Seabrook, 05000000
Issue date:	07/30/1987
From:	Varga S Office of Nuclear Reactor Regulation
To:	Piercebjorklun AFFILIATION NOT ASSIGNED
Shared Package
ML20236H087	List: ML20236H083 ML20236H148
References
NUDOCS 8708050056
Download: ML20236H083 (12)

Text

..

JUL 3 01987 Ms. Patricia Pierce-Bjorklund 15 Spring Street Essex, Massachusetts 01929

Dear Ms. Pierce-Bjorklund:

I have been asked to respond to your letter of May 30, 1987, to Chairman Zech, which detailed your concerns about the possibility of a loss.of-coolant accident (LOCA) at the PiloHm or Seabrook nuclear power plant.

You cited a number of issues that had been raised in the early 1970s regarding reactor core dynamics under LOCA conditions, modeling, and comments by officials.

Please let me assure you that these issues were duly considered in the formu-lation of the rule that has been used as a licensing basis for nuclear power plants in the United States.

In the ten years following the Emergency Core Cooling System (ECCS) rulemaking in 1974, the responsible U.S. government agencies, the nuclear industry in the United States, and foreign researchers have obtained considerable information on ECCS performance. The majority of the LOCA research is complete and has greatly improved the understanding of ECCS performance during a LOCA. This, in turn, has demonstrated the conservatism of the methods specified in the Commission's rules.

Enclosures A through G are being issued as part of our efforts to revise the ECCS rule in light of our current knowledge.

It provides background information on your concerns related to the state-of-knowledge on the ECCS, including a summary of ECCS research. Also available in the NRC Public Document Room is a draft report (NUREG-1230), dated April 1987, that provides additional information on ECCS research.

I trust that this is a satisfactory response to your concerns.

l Sincerely, I

Cdgini Sigi10d BJ l

1 Steven A. Varga, Director Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated

• See previous concurrence

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Ms. Patricia Pierce-Bjorklund 15 Spring Street Essex, Massachusetts 01929

Dear Ms. Pierce.Bjorklund:

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which detailed your concerns about the possibility of a J,8I, to Chairman Ze I have been asked to respond to your letter of May 30,19 oss-of-coolant accident (LOCA) at the Pilgrim or Seabrook nuclear powe'r plant.

You cited a number of issues that had been raised i the early 1970s regarding reactor core dynamics under LOCA conditions, mode ng, and comments by officials.

Please let me assure you that these issues were ly considered in the formu.

lation of the rule that has been used as a lice sing basis for nuclear power plants in the United States.

In the ten years foll ng the Emergency Co e Cooling System (ECCS) rulemaking in 1974, the responsibl

.S. government a encies, the nuclear industry in the United States, and foreig esearchers h e obtained considerable information on ECCS performance. The major ty,of the i CA research is complete and has greatly improved the understanding of ECCS perf rmance during a LOCA. This, in turn, s

has demonstrated the conservatism of he methods sperified in the Commission's rules.

N The enclosed document (SECY-86-318) datedOciobet28,1986, was issued as part of our efforts to revise the ECCS ule in the lightNf our current knouledge.

It provides substantial backgroun information on your c'encerns related to the state-of-knowledge on the ECCS, i cluding a summary of ECCS 'ressanch.

Also available in the NRC Public Docu;nent Rooms is a draft report (NUREC1230),Jated_

April 1987, that provides addit onal information on ECCS research.

I trust that this is a satisfa tory response to your concerns.

l

..Sjncerely,

, f'd' iginal Sicnod Py f

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Steven A7 Virga, Direitor

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Division of Reactor Projects I/II Office of Nuclear Reactor Regulation g

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Enclosure:

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Ms. Patricia Pierce-Bjorklund 15 Spring Street Essex, Massachusetts 01929

Dear Ms. Pierce-Bjorklund:

I have b en asked to respond to your letter of May 30, 1987, to Chairman Zech, which det iled your concerns about the possibility of a loss-of-coolant accident (

CA) at the Pilgrh or Seabrook nuclear power plants.

You cited a n ber of issues that had been raised in the early 1970s regarding reactor core dy mics under LOCA conditions, modeling, and comments by officials.

Please let me ass e you that these issues were duly considered in the formu-lation of the rule at has been used as a licensing basis for nuclear power plants in the United ates.

In the ten years followi the Emergency Core Cooling System (CCCS) rulemaking in 1974, the responsible U.. government agencies, the nuclear industry in the United States, and foreign r earchers have obtained considerable information on ECCS performance. The majorit of the LOCA research is complete and has greatly improved the understanding of E S performance during a LOCA. This in turn, has demonstrated the conservatism f the methods specified in the Commissions rules.

The enclosed document (SECY.86-318), da d October 28, 1986, was issued as part of our efforts to revise the ECCS rule in he light of our current knowledge.

It provides substantial background informat n on your concerns related to the state-of-knowledge on the ECCS, including a s

.ary of ECC3 research. Also available in the NRC Public Document Rooms is a aft report (NUREG-1230), dated April 1937, that provides additional information o ECCS research.

I trust that this is a satisfactory response to your c neerns.

Sincerely, Steven A. Varga, Director Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated

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I Ms. Patricia Pierce-Bjorklund 15 Spring Street Essex, Massachusetts 01929

Dear Ms. Pierce-Bjorklund:

I ha e been asked to respond to your letter of May 30, 1987, to Chairman Zech, which detailed your concerns about the possibility of a loss-of-coolant accide (LOCA) at the Pilgrim or Seabrook nuclear power plant.

You cited number of issues that had been raised in the early 1970s regarding reactor core dynamics under LOCA conditions, modeling, and comments by officials.

Please let me sure you that these issues were duly considered in the formu-lation of the r that has been used as a licensing basis for nuclear power i

l plants in the Unit States.

l l

In the ten years follo.ng the Emergency Core Cooling System (ECCS) rulemaking in 1974, the responsible

.S. government agencies, the nuclear industry in the United States, and foreign esearchers have obtained considerable information on ECCS performance. Therujo ty of the LOCA research is complete and has greatly improved the understanding of CCS performance during a LOCA.. This, in turn, has demonstrated the conservati s of the methods specified in the Comndssions rules.

The enclosed document (SECY.86-318),

ted October 28, 1986, was issued as part of our efforts to revise the ECCS rule the light of our current knowledge.

It provides substantial background inform ion on your concerns related to the state.of-knowledge on the ECCS, including a ummary of ECCS research. Also available in the NRC Public Document Rooms i a draft report (NUREG-1230), dated April 1987, that provides additional informati on ECCS research.

I trust that this is a satisfactory response to your concerns.

Since rely, l

Steven A. Varga, Director Division of Reactor Projects I/II Office of Nuclear Reactor Regulation l

l

Enclosure:

i As stated

• See previous concurrence OFC : ACTDIR/PDI-3*: CHIEF:RSB* : AD:DRP/NRR* :0:DRP/NRR

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OFFICIAL RECORD COPY l

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1 Ms. Pa ricia Pierce-Bjorklund j

15 Spri Street i

f Essex, Ma achusetts 01929

Dear Ms. Pie e-Bjorklund:

Your letter of.

30, 1987 to Chairman Zech was referred to me for response.

Issues raised in yo r letter concerning reactor core dynamics under.LOCA conditions, modeling nd comments by officials were duly considered in the formulation of the rul that has been used as a licensing basis for nuclear power plants.

I feel c fident that if you were to explore the voluminous records that exist in the ublic Document Room, you would find the l

considerations that went in o formulating the rule. These considerations have

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been on-going over the years sually as a result of additional research completed, additional experime ts performed, and additional analysis.done.

For example, the attached documen (SECY.86-318) regarding the~ publishing of a4 notice of proposed rulemaking revis' g the rule used as a licensing basis reflects the current state-of-knowle e on emergency core cooling system (ECCS) evaluation models an area in which you letter raises concerns.

In fact a draft I

report (NUREG 1230, dated April 1987) ha been issued which documents in detail the ECCS research that has been D*rformedN nd.the current knowledge of ECCS performance, i

If I may borrow a phrase from you "there is am e evidence" in the voluminous records to demonstrate the extensive considerat ons that went into the basis of the rule that has been used in licensing nucle power plants such as Seabrook.

Sincerely, Steven A. Varga, Director I

Division of Reactor Projects I/II Office of Nuclear Reactor Regulation l

ENCLOSURE:

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1 Ms. Patricia Pierce-Bjorklund 15 Spring Street Essex,M sachusetts 01929 Dear Ms.

erce-Bjorklund:

Your letter f May 30,1987 to Chaiman Zech was referred to me for response.

Issues raised b ck in the early 1970's cited in your letter concerning reactor core dynamics un er loss-of-coolant accident (LOCA) conditions, modeling and comments by offic 1s were duly considered in the formulation of the rule that has been used as a icensing basis for nuclear power plants.

In the ten years foll ing the Emergency Core Cooling System (ECCS) rulemaking in 1974, the responsib U.S. government agencies, the U.S. nuclear industry, and foreign researchers ave obtained considerable information on ECCS perfomance. The majorit of the LOCA research is complete and has greatly improved the understanding f ECCS performance during a LOCA which, in turn, has demonstrated the conserv tisms of the methods specified in the Commissions rules.

The enclosed document (SECY-86-3 ) dated October 28, 1986 was issued as part of our efforts to revise the ECCS ule in the light of our current knowledge.

It provides substantial background 'nformation on your concerns related to the state.of-knowledge on Emergency Core ooling System (ECCS) including a summary

~ f'ECCS research. Also, this documen is available in the Public Document o

Rooms a well as a draft report (NUREG-130), dated April 1987) which provides additional information on ECCS research.

I trust that this is a satisfactory respons to your concerns.

Sincerely, Steven A. Varga, frector Division of Reacto Projects I/II Office of Nuclear Re ctor Regulation

Enclosure:

As stated

• See previous concurrence OFC : ACTDIR/PDI-3*: CHIEF:RSB* : AD:PRP/NRR :D:DRP/NRR

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07/ /87 0FFICIAL RECORD COPY

I Ms. Patrici Pierce-Bjorklund 15 Spring Str et

{

Essex, Massach etts 01929 i

i

Dear Ms. Pierce-B ' rklund:

1 Your letter of May 1987 to Chairman Zech was referred to me for response.

l Issues raised in yourN, ttter concerning reactor core dynamics under l conditions, modeling andscomments by officials were duly considered in the formulation of the rule that has been used as a licensing basis for nuclear power plants.

The enclosed document (SECY-8 318) provides substantial background information on your concerns r ated to the state-of-knowledge on Emergency

)

Core Cooling System (ECCS).

Thi was published as part of our efforts related to a proposed rulemaking on ECCS.\\ Also, this document is available in the Public Document Rooms as well as a Nraft report (NUREG-1230, dated April 1987) which provides additional information on ECCS research.

i l

I trust that this is a satisfactory res onse to your. concerns.

Sincere 1

Steven A. Var a. Director Division of Rea\\ tor Projects I/II Office of NucleaV Reactor Regulation

Enclosure:

As stated

• See previous concurrence l

1 0FC :ACIDIR/PDI-3*: CHIEF:RSB* :AD:DRP/NRR :D:DRP/NRR NAME:VNerse['d4

lm :MHodges

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SVarga DATE :07/23/87 /fQ:07/ /87

07/ /87

07/ /87 OFFICIAL RECORD COPY l

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Nerses/jb Document Comments:

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FROM:

DUE:

-EDO CONTROL.CO2931 DOC DT: 05/30/87 i

PATRICIA PIERCE-BJORKLUND FINAL REPLY:

'l ESSEX, MASSACHUSETTS l{

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CHAIRMAN ZECH l

FOR SIGNATURE OF:

OREEN SECY NO: 87-660 a

i DESC:

-ROUTING:

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CONCERNING LOSS OF COOLANT ACCIDENT-IN THE REACTOR. CORE'AT SEAB Q K'OR PILGRIM.

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DATE: 06/10/G7 l

l ASSIGNED TO: NRR CONTACT: MURLEY L

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SPECIAL INSTRUCTIONS OR REMARKS:

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FOR APPROPRIATE ACTION l

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'STAROSTECKI BLAHA FUNCHES MOSSBURG

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CORRESPONDENCE' CONTROL TICKET.

PAPER NUMBER:

CRC-87-0660 LOGGING DATE: Jun. 9',87 ACTION OFFICE:

EDO AUTHOR:/

P. '..P-Bj orklund AFFILIATION:

MA (MASSACHUSETTS)

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LETTER DATE:

'May 30 87 FILE CODE:

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SUBJECT:

-plant

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1 ACTION:

Appropriate DISTRIBUTION:

I SPECIAL HANDLING: None I

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