ML19341B357
| ML19341B357 | |
| Person / Time | |
|---|---|
| Issue date: | 12/05/1980 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-1795, NUDOCS 8101300790 | |
| Download: ML19341B357 (3) | |
Text
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.a Y/ MINUTES OF THE NOV 13, 1980 FLUID DYNAMI N
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SUBCOMMITTEE MEETING BURLINGAME, CA G
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PURPOSE: The Subcomittee met to discuss the NucleDyne Engineering Corp
' M,N. s Passive Containment System.
, a. s '.o ATTENDEES:
ACRS OTHER M. Plesset J. Sprung - DOE W. Mathis
- 0. B. Falls - NucleDyne I. Catton - Consultant F. Klemila - NucleDyne
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Z. Zudans - Consultant J. Leininger - Gilbert /
A. Bates - Staff
- Comonwealth K. Vashi - Westinghouse MEETING REVIEW:
1.
Mr. O. B. Falls reviewed the design concept for the Passive Containment System (PCS). PCS uses a high pressure (75 psia), small volume (250,000 ft3) primary system containment with a number of water filled quench and deluge tanks to cope with loss of fluid accidents. Each of the major primary system cor@o-nents is housed in its own steel shell and connected together by steel lined cells containing the primary system piping. During a LOCA, steam from the primary system is quenched in the deluge tanks and the quench tanks. When the primary syste:n reaches 1000 psia check valves open and water enters the primary system from the refill tanks. The system contains adequate water to absorb the stored energy in the primary system as well as decay heat for a number of hours (approx four). Relief and safety valves on the primary side as well as the secondary side safety valves discharge to the quench tanks. A heat removal system for decay heat rejection would be driven by natural circu'tation.
The primary containment system is surrounded by and supported by a reinforced concrete structure which serves as the reactor building and a secondary contain-i ment structure. Layout of these structures, with a low center of gravity and embedment in the ground is designed to reduce seismic amplification up through structures.
NucleDyne believes that the PCS system could provide considerable improvements in the safety of nuclear power plants.
- Designated Federal Employee 8101300'7 9
2-November 13, 1980 Fluid D:mamics 2.
Mr. J. Sprung, Sandia, indicated that 00E had sponsored a program to review several aspects of the PCS. Through contracts with Gilbert / Commonwealth Associates and W a number of questions dealing with the question of whether the cencept would work were addressed.
3.
Mr. J. Leininger, Gilbert /Cocnonwealth Associates, indicated that they believed that the PCS concept does not have any clearly unworkable aspects; how-ever, certain modifications would be necessary to the design to accomodate difficulties in construction and structural aspects. ECCS calculations indicate that peak containment pressures might be closer to 300 psia than 75 and that transfer of component support forces through the free standing primary containment to the concrete structures would be difficult.
In addition the primary system would have to be modified in order to accommodate the containment design. The Gilbert / Commonwealth Report also indicated that the construction cost could be higher than for conventional containments.
4.
Dr. K. Vashi, W, reviewed their-response to two questions posed by Sandia.
He indicated that a qualitative evaluation indicated that the primary system pipe whip restraints could not be eliminated in the PCS and that it would be necessary
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to modify (without too much difficulty) the ccrnponent supports and the PCS structures to accommodate the primary cystem. The PCS component cells would have to be enlarged for the RCP and Steam Generator. This would require that the center-to-center distance from the vessel to the RCPs and SG be increased, and would probably require the addition of seismic restraints on primary system piping which are not now needed.
S.
Dr. I. Catton sumarized his review of the PCS for the Subcommittee. He expressed a number of concerns with regard to connection of a number of systems with check valves which are prone to leakage, steam condensation loads and the design of the quench systts, inadequacies in the ECCS modeling (not enough _
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information was available to clearly understand what assumptions were made or EM or other), inadequate analysis of small breaks (particularly for those whose pressure does not fall below 1000 psia), and a lack of backup support to verify or allow evaluation of all of the safety gains from the PCS.
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Nohember 20, 1980 Fluid Dynamics..
Dr. Z. Zudans sumarized his rehiew indicating that the function of the PCS 6.
would depend on the cooling of the primary containment steel walls so as to ahoid unacceptable thermal stresses. He indicated that one could not accomodate the thennal-stress that would occur without the cooling. It would also be exceedingly difficult to construct the containment structures. The proper opera-tion of the system and isolation of secondary systems from the primary system also relies on check valves which will leak. This was one of the principle risk areas in WASH-1400 for Surry and it is not clear that the PCS is any less risky in this respect.
Mr. O. B. Falls indicated that he beliehed that the concerns expressed could 7.
be adequately addressed by NucleDyne and that they would do so.
Dr. Plesset indicated that it was not clear that ehen if the PCS could be 8.
built and operated that the cherall risk would be better than standard contain-Some risk analysis and comparison would be needed to make this chaluation.
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