NUREG-1068, Responds to Constituent Inquiry Re Nuclear Reactor Containment Sys Designed by G.E.Probability of Severe Reactor Accidents Quite Low.Third Party Liability Insurance Provided Under Price-Anderson Legislation.W/O Stated Encls

Responds to Constituent Inquiry Re Nuclear Reactor Containment Sys Designed by G.E.Probability of Severe Reactor Accidents Quite Low.Third Party Liability Insurance Provided Under Price-Anderson Legislation.W/O Stated Encls

ML20206Q477
Person / Time
Site:	Peach Bottom, Limerick, 05000000
Issue date:	08/26/1986
From:	Stello V NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	Schulze R HOUSE OF REP.
Shared Package
ML20206Q484	List: ML20206Q485 NUREG-1068, Responds to Constituent Inquiry Re Nuclear Reactor Containment Sys Designed by G.E.Probability of Severe Reactor Accidents Quite Low.Third Party Liability Insurance Provided Under Price-Anderson Legislation.W/O Stated Encls
References
RTR-NUREG-0974, RTR-NUREG-1068, RTR-NUREG-1968, RTR-NUREG-974 NUDOCS 8609040423
Download: ML20206Q477 (4)

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JTaylor Denton/Vollmer TMurley PFAS GCunningham Mossburg (2023)

AUG 2 61986 0CA Brandenberg (2023)

SECY E00 R/F VStello RBernero PDR RHouston The Honorable Richard T. Schulze Central Files RHouston R/F Member, United States House of Representatives 2 East Lancaster Avenue Paoli, Pennsylvania 19301

Dear Congressman Schulze:

By your letter to Mr. Harold Denton dated August 5,1986 you requested comments on concerns expressed by some of your constituents regarding nuclear reactor containment systems designed by the General Electric Co. These concerns derived from a newspaper article that dealt with the Mark I containment design (The Philadelphia Electric Ca. Peach Bottom Units 2 and 3 are two of 24 licensed units in the United States that have this particular design). The Limerick facility near Pottstown has a Mark II containment design, which is a different configuration frc'n the Mark I but is similar in the sense that it employs a pressure suppression principle that forces steam, that would be released from the largest possiole pipe break in the primary reactor coolant system, to be condensed in a large pool of water inside containment. This limits the internal pressure that the containment would experience during such a postulated serious accident and establishes the minimum acceptable design basis pressure specification. All of the General Electric containment designs have substantial safety margin over and above this design pressure before actual structural failure would be expected to occur, and meet the Commission's requirements for assurance of containment integrity.

Nevertheless the Commission has long recognized the possibility of even more serious but very low probability accidents that can result from a multiplicity of failures in a nuclear power plant and lead to total and extended loss of cooling water to the reactor and substantial or total melting of the reactor core. The Commission currently refers to such events as severe accidents to distinguish them from postulated design basis accidents. Some of these events have the potential for leading to stresses which could cause containment failure, particularly if operating personnel do not take actions that may be available to them.

The NRC staff is currently in the process of implementing activities called for by the Commission in its " Policy Statement on Severe Reactor Accidents Regarding Future Designs and Existing Plants" that was published in the Federal Register on August 8, 1985 (copy enclosed). A reading of the relevant portions of this statement will provide inforrrative background on both NRC and nuclear industry activities on this issue, as well as the general nature of ,; ,

policy implementation specific to operating plants. It is in this context g,V that the NRC staff has recently taken initiatives to identify specific - 0 objectives and potential modifications of BWR containments to improve the {'

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It should be of particular interest to you, however, that the Limerick plant is one that has had a detailed severe accident risk assessment study performed.

This study was requested by the staff in May 1980 due to a combination of factors which included the high population densities in the vicinity of the Limerick facility. The study was submitted in two complementary parts by the

Philadelphia Electric Company, titled a Probabilistic Risk Assessment and a Severe Accident Risk Assessment. The study was evaluated during the operating license review of the Limerick Unit 1 facility and the results were published in the staff's Final Environmental Statement (NUREG-0974, April 1984) with respect to the potential environmental impacts of accidents and in the staff report " Review Insights on the Probabilistic Risk Assessments for the Limerick Generating Station" (NUREG 1068, August 1984) (copy enclosed). Both of these documents may be found in the Local Public Document Room in the Pottstown a Public Library. As pointed out in the NUREG-1968 report, this study prompted the plant owner to make some changes that improved the margin of safety, but also affirms that the risk to the public from the operation of the plant is quite low.

The Commission recognizes that it is not possible to achieve absolute zero risk but is dedicated to taking appropriate steps to achieve reasonable assurance that the likelihood of occurrence of severe core melt accidents is very low and that containments have substantial capability to mitigate their consequences if one should occur. The complexity of the phenomena of severe accidents requires careful and extensive analysis to identify potential severe accident vulnerabilities, and care to assure that conceptual improve-ments do not in themselves create new safety problems before they are implemented.

With respect to the matter of the property insurance question raised by your constituents, as I am sure you are aware, third party liability insurance coverage has been provided under the terms of Price-Anderson legislation which r is currently before the Congress for renewal.

Sincerely, (siemed) T. A.hha hVictorStello,Jr.

Executive Director for Operations

Enclosures:

1. Federal Register, dated 8/8/85

2. NUREG-1068, dated 8/84 SEE ATTACHED PAGE FOR PREVIOUS CONCURRENCES, 0FC : DDIR/BWR  : DIR/BWR  : DDIR/NRR : DIR/NRR  : ED0 OCA  :

.____:.___________:..._________:____..___.__:__..._____._:..____7______:: ____________:___________

NAME : RWHouston:no RBernero : RVollmer : HRDenton : VSt'eIlo  :  : :

j DATE : 8/ 19 /86  : 8/ 20 /86 : 8/ 21 /86 : 8/ 21 /86 : 8/ : i /86 : 8/ /86 :

0FFICIAL RECORD COPY i

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It should be of particular interest to you, however, that .the Limerick plant

/

j is one that has had\a detailed severe accident risk assessment study performed.

I This study was requested by the staff in May 1980 due to'a combination of

factors which included'the high population densities ip'the vicinity of the

Limerick facility. The study was submitted in two complementary parts by the l Philadelphia Electric Company, titled a Probabilistic Risk Assessment and a 1 Severe Accident Risk Assessment. The study was evaluated during the operating

! license review of the Limerick Unit 1 facility and the results were published 1 in the staff's Final Environme'ntal Statement (NUREG-0974, April 1984) with respect to the potential environmental impacts,0f accidents and in the staff i

' report " Review Insights on the Pr'obabilistic Jtisk Assessments for the Limerick Generating Station" (NUREG 1068, August 1984) (copy enclosed). Both of these

, documents may be found in the Local Public, Document Room in the Pottstown Public Library. As pointed out in the NUREG-1968 x report, this study prompted j the plant owner to make some changes that' improved the margin of safety, but l also affirms that the risk to the public'from the operation of the plant is quite low. \

j The Commission recognizes that it is not possible to achieve absolute zero

risk but is dedicated to taking appropriate st'eps to achieve substantial assurance that the likelihood of, occurrence of severe core melt accidents is very low and that containments have substantial capability to mitigate their consequences if one should occur. The complexity of the phenomena of  !

severe accidents requires care'ful and extensive analysis to identify potential severe accident vulnerabilities, and care to assure that conceptual improve-l

mentsdonotinthemselves/createnewsafetyproblems\beforetheyare implemented. \

With respect to the matter of the property insurance question raised by your i constituents, as I am sure you are aware, third party liability insurance i coverage has been provided under the terms of Price-Anderson' legislation which i is currently before the Congress for renewal.

Sincerely, i \

! Victor Stello, Jr.

Executive Director i for Operations l

Enclosures:

i 1. Federal Register, dated 8/8/85

2. NUREG-1068, dated 8/84 '

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v J G EDO PRINCIPAL CORRESPONDENCE CONTROL FROM: DUE: 08/22/86 EDO CONTROL: 002023 DOC DT: 08/05/86 REP. DICK SCHULZE FINAL REPLY:

TO:

DENTON FOR SIONATURE OF: ** OREEN ** SECY NO:

EXECUTIVE DIRECTOR DESC: ROUTING:

ENCLOSES LEITER FROM WELLS, WELLS, LOEBEN, TAYLOR HOFFMAN & HOLLOWAY RE ARTICLE IN WALL STREET MURLEY JOURNAL REGARDING THE GE MARK I CONTAINMENT OCUNNINGHAM SYSTEM OCA SECY DATE: 08/08/86 ASSIGNED TO: NRR CONTACT: DENTON SPE IAL INSTRUCTIONS OR REMARKS:

, REPLY TO PAOLI, PENNSYLVANIA OFFICC.

NRR RECElVED: AUGUST 8, 1986 ACTION: , . 'DSL::BERNER0-a

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NRR ROUTING: DENTON/VOLLMER PPAS MOSSBURG -

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