ML20236D150

Advises That Encl Draft Memo to Ja Calvo Summarizing 871014 Meeting W/Util Re Application of Severe Accident Policy to Plant Provided to Util

ML20236D150
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/23/1987
From:	Heitner K NRC
To:	NRC
References
NUDOCS 8710280043
Download: ML20236D150 (3)

Text

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UJ E WASHINGTON. D. C. 20555 F

Jnse A..Calvo, Director

< 'j MEMORANDUM FOR: '

Pr6 ject Directorate .IV ,. '4 .

Division of Reactor Projects - III, U 'f._.

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• IV, V and Special Rrojects

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d FROM:

^' Kenneth'L. Heitner, Project Manager; ,

"' .l Project-Directorate-IV 4 Division of~ Reactor Projects LIII, IV, V and Special Projects

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SUMMARY

OF MEETING TO DISCUSS APPLICATI0H:

OF SEVERE ACCIDENT POLICY TO FORT ST. VRAIN

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ON OCTOBER 14, 1987  ; ~

1 This meeting was requested by Public Service Company of Colorado (PSC), the licensee for Fort St. Vrain (FSV). The meeting was requested as a foMow-up

't.o the meeting conducted by the staff on June 29, 1987, during which the staff

' discussed the implementation of the Commission's Severe Accident Policy. The >

attendees at this meeting are listed in Enclosure 1.

The staff noted that the Generic Letter (GL) concerning Severe, Accident Policy implementation was still in preparation, The GL would contain guidance for .

all licensees in responding to the policy. The initial focus of the individual plant examinations (IPEs) would be' internal events. The licensees would be, encouraged to use one of thr9e methods for the Ife ~These are:

P[obabilidtic Risk Assessmerrt P W b

1) X ID' CORE Methodology,'or . -

2)

3) Otlier systematic odiuation methods i . V nt ,

The licensees would be asked to identify dominant accipg/(/sequenceos.for th (Dominant sequences have a probability of 2x10 plant.

The utility would be asked to evaluate cost effective methods of reducing the .

probability of that accident sequence. ]

The staff would then review the IPE, and either accept the licensees analys'i X External events would be l

[ or request additional-risk reduction measures.In addition to the IPE's the licensees us l l

treated separately /'on a longer schedule. j L

would also be requested to respond on their programs for accident management

' and training for severe accidents. The staff requested PSC to make specific proposals to respond to the policy for FSV. i i

PSC responded by noting that FSV's behavipa in severe accident sequences was  :

different than for light water reactors. Although the FSV core will be damaged l (release fission geometrychanges) products)athightemperatures,actualcoreme x is not expec ted to occur. PSC has examined both the frequency However, PSC noted and consequences of a numoer of severe accident sequences.

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'certain shortcomings with this approach. Specifically,.PSC expressed concern i about the validity of the frequency estimates, given the limited f ailure data I on'some FSV systems. PSC also noted that the consequences of these events are j

all .within 10 CFR Part 100 limits. l The staff emphasized the accurate frequency data was not essential to the i IPE. FSV experience could potentially be supplemented by experience from l j

European gas cooled reactors g

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%The staff also ~ observed that it was possible to start with identified i

" vulnerabilities" and examine ways of correcting those vulnerabilities. Also, since the IPE's would be developed on a best estimate basis, examination of uncertainties in the estimates could be deferred. The staff emphasized that the need for a systematic approach was important. For a unique plant such as l' FSV this was important, because the plant could have unique vulnerabilities.

The staff and PSC agreed to hold additional meetings as PSC developed its t approach to the Severe Accident Policy.

Note: A previous PRA developed for FSV was submitted in a PSC letter dated ,

March 28, 1983 (P-83124),. Docket No. 50-267. l l

i Kenneth L. Heitner, Project Manager i

Project Directorate - IV l Division of Reactor Projects - III, i IV, V and Special Projects

Enclosure:

As stated cc w/ enclosure: '

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