ML20153G865

Forwards Responses to Five Questions from Monroe City-County Ofc of Civil Preparedness Re Facility.Chances of Meltdown & Severe Accidents Discussed.Comments Requested by 880506

ML20153G865
Person / Time
Site:	Fermi
Issue date:	04/29/1988
From:	Muller D Office of Nuclear Reactor Regulation
To:	Gillespie F, Thadani A Office of Nuclear Reactor Regulation
References
TAC-67894, NUDOCS 8805120040
Download: ML20153G865 (6)

Text

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April 29, 1988

. s Docket No. 50-341 Frank P. Gillespie, Director

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MEMORANDUM FOR:

Program Management, Policy Development & Analysis Staff Ashok Thadani, Assistant Director for Systems Division of Engineering and System Technology FROM: Daniel R. Muller, Acting Director Project Directorate III-1 Division of Reactor Projects - III, IV, V

& Special Projects

SUBJECT:

REGION III TIA ON QU:STIONS FROM MONROE CITY-COUNTY REGARDING FERMI-2 (TAC NO. 67894)

An April 12, 1988 TIA from Region III requested NRR assistance in responding to five questions from the Monroe City-County Office of Civil Preparedness. The responses to the first four questions have been prepared by utilizing the information supplied in a draft letter to the The Honorable Lloyd Bentsen forwarded by NRR to the E00 on March 28, 1988 (EDO Green Ticket Number 3530 copy enclosed). Please provide your comments / corrections to these responses no later than May 6,1988 0tiginal signed by Daniel R. Muller, Acting Director ProjectDirectorateIII-1 Division of Reactor Projects III, IV, V

& Special Projects

Enclosure:

As stated PD3 SP /0 0 DRSP D$ GH AN DCR T IELD 4/d/8 4 4/ 8

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DISTRIBUTION

DOCKETFILE NRC~& LOCAL POR PD31 MEMO FILE DMULLER TQUAY RINGRAM 880512004o 900429 yDR ADOCK 05000341 PDR

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ENCLOSURE Monroe City-County Question:

1. What are the chances of a meltdown at Fermi 2?

Response

The most recent thorough study of severe accidents has been published in Draft NUREG-1150 (February,1987) "Reactor Risk Reference Document." This study included analyses of different reactor designs; one of those studied was a BWR Mark I reactor, namely the Peach Bottom nuclear plant. The Peach Bottom plant as a Mark I design is similar to Fermi-2 in reactor and containment design.

The results of this study indicated an estimated mean frequency of core damage (i.e., core melt) to be approximately one chance in 100,000 per year of

- operations. These results are consistent with NRC's belief that core melt accidents are very unlikely.

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.g-Monroe City-County Question:

2. What are the chances of a severe accident?

Draft NUREG-1150 also investigated the probability of early containment failure following a core melt. It is this issue which has attracted considerable attention to Mark I reactors since the study concluded that there is large uncertainty regarding the probability of early containment failure for these extremely unlikely accidents. As a result of the study documented in Draft NUREG-1150, it was concluded that the containment failure probability for Peach Bottom, a Mark I reactor, could range from 10 to 90 percent, albeit for highly improbable accidents.

Even allowing the large uncertainties which result in a higher upper value for containment failure, the Draft NUREG-1150 study estimated that the probability of a large reactor accident that results in one or more early fatalities ranged from one in one million to one in one billion. Given a severe accider,t, the probabilities of very high radiation exposure and the distances over which they would occur were also estimated to be reasonably small. :he risk levels for Fermi-2 or other Mark I reactors would of course, depend on its actual core melt probability, containment behavior, the local demography, and could vary somewhat from the results presented in Draft NUREG-1150. The results of this and related studies do, however, support the overall conclusion of low severe accident risk of nuclear reactors.

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Monroe City-County Question:

3. The NRC recently released NUREG 1150, in which the steel lining [of] Mark I reactors are reported to melt in a few minutes in an accident. Why is Fermi 2 allowed to continue to operate with this new information?

Response

See the response to question number 2.

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Monroe. City-County Question:

4. In addition to the melting of the steel lining the NRC has. stated Fermi 2's containment has a 90% chance of failure in an accident. Why has this plant been given an operating license to operate with this type of peril?

Response

See the response to question 2.

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Monroe City-County Question:

5. What are the exemptions that Detroit Edison has received in regard to complying with license conditions and safety regulations required by the NRC's standards and laws?

Response

The following exemptions have been granted for Fermi:

DATE DESCRIPTION April 15, 1988 - Exemption form Paragraph III.D.3 of Appendix J to 10 CFR Part 50. This allows for a one-time exemption to the testing of the interior containment isolation valves for the RHR system (three valves).

November 13, 1987 Exemption to GDC 56, Appendix A of 10 CFR Part 50, for Primary Containment Radiation Monitor Isolation Valves.

July 31, 1986 Exemption to GDC 56, Appendix A of 10 CFR Part 50. This exemption permits postponement of full compliance with GDC 56 for the traversing in-core probe (TIP) nitrogen purge line until the first scheduled refueling outage.

July 30, 1986 Exemption to 10 CFR 50.44. Permits postponement of the inerting of the Fermi-2 primary containment from December 21, 1985, until either completion of the startup test program or until the reactor has operated for 120 effective full power days.

July 24, 1986 Exemption to GDC 56, Appendix A of 10 CFR Part 50.

Limited period to allow a single penetration to have two '

isolation valves outside containment rather than one valve inside and one valve outside containment. Exemption would extend until the first scheduled refueling outage.

July 11, 1985 Exemption to 10 CFR Part 50, Appendix E. This exemption would delay the conduct of a full participation offsite emergency planning exercise. (Section IV.F of Appendix E requires that this exercise be conducted within one year before the issuance of the first operating license at the site for full power and prior to operation above 5% of rated power. The exercise was scheduled for October.

April 11, 1985 Partial exemptions from Appendix J of 10 CFR Part 50. The exemptions would (1) allow Type C testing of the main steam isolation valves to be conducted at a differential pressure less than that required by Paragraph III.C.2 of Appendix J, and (2) eliminate the full pressure test required by Paragraph III.D.2(b)(ii) of Appendix J for normal air lock opening and substitute a seal leakage test to be conducted at a pressure specified in the Technical Specifications.

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