ML19294C156
| ML19294C156 | |
| Person / Time | |
|---|---|
| Issue date: | 12/06/1979 |
| From: | Stampelos J Advisory Committee on Reactor Safeguards |
| To: | Bender M Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-SM-0163, ACRS-SM-163, NUDOCS 8003070230 | |
| Download: ML19294C156 (2) | |
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p December 6, 1979 Meyer Bender POSSIBLE SUGGESTICNS FOR '1EE INCORPORATION OF GERMAN EWR IDEAS IN U.S. PWRs h is report summarizes some possible design advantages found in the Mulhein-Karlich (MK) PWR which were included in my report to you of October 30, 1979 (German Variations in PWR Design).
1.
We MK containment is a steel sphere designed for an. internal pressure of 84 psia. We steel sphere is located within a concrete building. A large, strong, leakproof building should be the first step in designing a reactor plant. If the additional space affored by the choice of a large containment is properly utilized, a considerable savings in dollars an3 man-rem will occur during maintenance operations. We idea of space for maintenance may apply to auxiliary buildings as well. We degree of space utilization for different containments (eg. Cherokee, Perkins, and Oconee Plants of Duke Power) can be studied to determine whether the large containment really aids maintenance and surveillance.
2.
We MK contairment has diverse isolation signals. %e Germans believe that the contaiment spray system cx>mplicates the ECCS and is ineffective.
We spray system is operator actuated at MK and is not required for licens-ing. P aping of the containment sm p must be deliberately performed by the operator in the MK design.
3.
We MK plant has multiple dedicated auxiliary (emergency) feedwater systems.
We closed-loop system bleeds steam from the steam generators into auxiliary condensers. Potentially radioactive steam is not bled to the atmospiere.
We effects of a loss of power may not be as pronounced in the smaller auxiliary condensers as does occur in the large main turbine condenser.
Steam condensed in these auxiliary condensers flows by gravity to the feedpump suction.
4.
We MK plant has multiple dedicated ECCSS. We accmulator (core flood tank) capacity in the MK plant is over 3 times as large as in the correspondire U.S. plant.
5.
We MK PORV has a " pressure tap" direct valte position indication system.
Details of the system are unknown. We MK plant includes 2 A'IWS safety valves.
6.
%e MK fuel element storage pit is included within the contaiment.
80080702 30 w
o Meyer Bender
-2.
December 6, 1979 7.
%e MK off-gas treatment system employs a decontamination vessel and holdups throur3h activated charcoal filters (details unknown).
8.
W e emergency feedwater system for MK is classified and designed as a Consequently, all valves in the MK system which can safety system.
significantly affect the ability of the emergency FW system to fulfill its function and which may be repositioned either for operation or testing have notor operators which will be properly positioned by a
% is signal has priority E
RPS signal in the event of a system actuation.
so that even in the presence of a contradicting operational or test comm nd the action will take place. W ese valves, if improperly closed,.
would cause a safety grade alarm in the MK control room when anved from the operhtional readiness position. In the MK design a status indication lamp is provided for each active safety component as a further aid in recognizing improperly positioned valves. In the absence of a protection system cogrrard, the lamp is out. In the presence of a commard when the component is not in the commanded condition, the lamp blinks. We lamp burns steadily when the component has achieved the com mnded condition.
In order to better control small break IDCAs the MK emergency feedwater 9.
system is programed to increase the steam generator secondary inventory.
his Pressure in the steam generator is controlled at about 700 psia.
provides the possibility for a rapid temperature and pressure decrease We for the primary side through heat transfer to the steam generator.
saturation temperature for 700 psia is 503 F.
We MK plant has a flux rate of change trip which I asstrae is used when 10.
W e comparative U.S. plant employs operating below the power range.
excore detectorn to sense L nuclear power imbalance which will occur for a rod withdrawl typc accident. This diverse method of providirg protection for the same transient should be investigated.
John G. Sts.apelos ACRS Fellow cc: ACRS Members ACRS Technical Staff
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