ML20127C025

Forwards Request for Addl Info Re Hydrogen Control for Mark III Containment Plants During Postulated Degraded Core Accidents.Questions Should Be Transmitted to Grand Gulf, Perry,River Bend & Clinton Applicants

ML20127C025
Person / Time
Site:	Perry, Grand Gulf, River Bend, Clinton, 05000000
Issue date:	08/24/1984
From:	Butler W Office of Nuclear Reactor Regulation
To:	Schwencer A, Youngblood B Office of Nuclear Reactor Regulation
Shared Package
ML18041A119	List: ML20126E685 ML20127A380 ML20127C025
References
FOIA-85-76 NUDOCS 8409050617
Download: ML20127C025 (3)

Text

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f*gsh *1C*g ' UNITED STATES y

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g NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C.,20555 c . g, j August 24, 1984 MEMORANDUM FOR: B. J. Youngblood, Chief Licensing Branch No. 1. DL

' A. Schwencer, Chief Licensing Branch No. 2, DL FROM: W. R. Butler, Chief j Containment Systems Branch, DSI

SUBJECT:

REQUEST FOR INFORMATION REGARDING HYDROGEN CONTROL FOR MARK III CONTAINMENTS As part of our continuing review of hydrogen control for Mark III containment plants during postulated degraded core accidents, we have identified the need for additional infonnation on several matters. The .

items pertain to the CLASIX-3 code, which has been used by HCOG to l support the determining, the licensing activities environmental as.sociated conditions againstwith Mark which III plants; e.g.,

equipment survivability is to be evaluated. _ _

The CSB requests that the ciselosed questions be transmitted to

.the Grand Gulf, Perry, River Bend and Clinton applicants.

N W. R. Butler, Chief Containment Systems Branch, DSI

Enclosure:

As stated cc: R. W. Houston

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E. J. Weink~am B. Siegel ,

D. Houston CONTACT: A. Notafrancesco, CSB: DSI x29487 e

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. REQUEST FOR ADDITIONAL INFORMATION RELATED TO DEGRADED CORE HYDROGEN CONTROL 4

1. It is the intent of the Mark III owners to use the HC06 quarter-scale

. . tests',(whichfocusesondiffusion-typeburningwithinthewetwell i

region)andplantspecific/HCOGCLASIX-3 analyses (whichfocuseson discrete-type burning within the containment), to determine the most severe thermal environment within the containment and drywell for purposes of demonstrating equipment survivability. Since the present passive heat sink modeling in CLASIX-3 tends to underestimate the compartment atmosphere temperatures and since CLASIX-3 appears to be in non-conformance with the provisions of NUREG-0588, the CLASIXs3 containment response sensitivity studies (correspondence

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No. HGW-001) shsaid not be used as the baefs for determining the-I

most severe compartment temperature conditions. In view of this j concern, the present version of CLASIX-3 is inappropriate.  ;

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f Since the methodology described in NUREG-0588 is generally recognized as an acceptable approach for addressing equipment qualification, describe and justify if there are deviations from the provisions of NUREG-0588 with regard to the passive heat-sink and heat-transf.er

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assumptions that will be used for plant specific analyses in the .

4 following areas:

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1) the temperature difference used with the heat-transfer film coefficients for both saturated and super-heated atmospheres;- 1 S

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2) "the inalytical.model and assumptions used to account for condensate removal'from the heat sink surface; and

3) the energy removal associated with condensed mass.

2. For each postulated degraded core sequence, (i.e., SORV and drywell break initiated events), provide an evaluation of the impact on the drywell atmosphere environment when considering heat losses from the reactor vessel and its associated piping (e.g., SRV lines). Provide and justify assumptions used in your evaluation, e.g., convective and radiatiye heat transfer parameters. ,__ _

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3. According to the BWR/6 Standard Technical Specifications, periodic low pressure leak testing of the drywell is required. The .

acceptance criterion is that the leakage shall be less than or equal to 10% of~ the maximum allowable A/fii (i.e., approximately 1 ft* ).

_Thus, the maximum allowable leak rate is equivalent to roughly 4000 SCFM at 3 psi pressure differential. Provide an evaluation of the l

consequences within the drywell and the containment by the combustion of hyd[ ogen when considering the drywell bypass le'akage (include mechanistically the effects of upper pool dump and pool drawdown). l x

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