ML20137X481

Forwards Research Results Utilization Form for Ril 144, Effect of Hydrogen Gas on Downcomer Fluid Temps During TMI Accident

ML20137X481
Person / Time
Site:	Three Mile Island
Issue date:	11/25/1985
From:	Rosztoczy Z Office of Nuclear Reactor Regulation
To:	Burda A NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
CON-FIN-G-1047 NUDOCS 8512100532
Download: ML20137X481 (2)

Text

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• k$W/263 NEMORANDUM FOR: Alois Burda, Chief Program Planning and Control Branch Policy Planning and Control Staff, RES FROM: Zoltan Rosztoczy, Chief Research & Standards Coordination Branch Division of Safety Technology, NRR

SUBJECT:

RESEARCH RESULTS UTILIZATION FORM FOR RIL #144 I am forwarding herewith the Research Results Utilization Form for RIL #144, "The Ettect of Hydrogen Gas on Downcomer Fluid Temperatures During the TMI Accident."

4 .//x _ ' @k. Q .]La u~m Zoltan Rosztoczy, Chief /

Research & Standards Coordination Branch Division of Safety Technology Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: H. Denton T. Speis R. Bernero H. Thompson J. P. Knight W. Russell F. Schroeder 8512100532 851125 0 DR ADOCK 0500

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. .s

, OFFICIAL PROGRAM OFFICE COMMENTS ON UTILIZATION OR VALUE OF RIL TO Tile REGULATORY PROCESS

. . (Research Results Utilization Form)

RIL f: 144 ~ Date Issued:10/9/85 RRG:

Generic Issues Branch / DST l .

RIL

Title:

The Effect of Hydrogen Gas on Downcomer Fluid Temperatures During the TMI Accident

! Program Office: RES Contact Name: R. Woods /J. Reyes Date: 11/22/85 j Application to Regulatory Process: ,

Performed under a Grant to Purdue University (G-1047) dScaling of Mixing in Thermally Stratified Flow", this

. work was in support of the NRR's pressurized thermal shock (PTS) study. Reported therein is a specific study by Professor T. G. Theofanous of phenomena in the cold legs and downcomer starting 200 minutes into the TMI

accident. The TMI accident was one of the actual operating events considered in development of the PTS rule, and this re-analysis by Prof. Theofanous contains a more detailed model to account"for the effects of hydrogen gas than previous analyses. ,.

Impact of Results: .

The new analyses describe phenomena whereby the accumulation of hydrogen in the cold legs would inhibit the mixing of steain and the cold HPI water resulting in less heating of the water impiriging locally on the reactor vessel. Parametric studies indicate the potential for wall temperatures lower than those considered .

in establishing the PTS screening criteria. The NRR review agrees that for the conditions considered, there.

would be a potential for lower wall temperatures, however, when considering the uniqueness of the failures, the actions, the timing and-consequences of the TMI accident relative to the other events considered in the PTS study, no change in sereening criteria is justified * ,

~.

Comments / Remarks:

The analyses have been provided to the groups who are studying severe accidept consequences for consideration in developing guidance and procedures for recovery from severe accidents. An October 2, 1985 memorandum from the EDO to the Commissioners acknowledges this research and relates it to the PTS studies.

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