ML20031D706
| ML20031D706 | |
| Person / Time | |
|---|---|
| Site: | Allens Creek File:Houston Lighting and Power Company icon.png |
| Issue date: | 05/01/1975 |
| From: | US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML20031D662 | List: |
| References | |
| NUDOCS 8110140032 | |
| Download: ML20031D706 (3) | |
Text
,
ENCLOSURE TOPICAL REPORT EVALUATION Report and Date:
WCAP-7709-L (Proprietary), " Electrical Hydrogen Recombiner for Water Reactor Containments" (July 1971)
WCAP-7820 (Non-proprietary), " Electrical Hydrogen Recombiner
f.or Water Reactor Containments" (December 1971)
WCAP-7709-L Supplement 1 (Proprietary), " Electric Hydrogen P,ecombinerforPWRContainments"(April 1972)
WCAP-7820 Supplement 1 (Non-proprietary), " Electric Hydrogen Recombiner for PWR Containments" (May 1972)
WCAP-7709-L Supplement 2 (Proprietary), " Electric Hydrogen Recombiner for PWR Containments Equipment Qualification Report" (September 1973)
WCAP-7820 Supplement 2 (Non-proprietary), " Electric Hydrogen Recombiner for PWR Containments F^flipment Qualification Report" (October 1973)
WCAP-7709-L Supplement 3 (Proprietary), " Electric Hydrogen Recombiner for PWR Containments Long Term Tests" (January 1974)
WCAP-7820 Supplement 3 (Non-proprietary), " Electric Hydrogen Recombiner for PWR Containments Long Term Tests" (February 1974)
WCAP-7709-1 Supplement 4 (Proprietary), " Electric Hydrogen RecombinerforPWRContainments"(April 1974)
WCAP-7820 Supplement 4 (Non-Proprietary), " Electric Hydrogen RecombinerforPWRContainments"(May1974)
Originating Organization: Westinghouse Electric Corporation Reviewed By: Electrical, Instrumentation and Controls Systems Branch, Mechanical Engineering Branch and Containment Systems Branch, Office of Nuclear Reactor Regulation MAY 011975 8110140032 011009 PDR ADOCK 05000 6
m W
. Sumary of Topical Recort Westinghouse Electric Corporation has developed an electric hydrogen recombiner as part of the combustible gas control system to control hydrogen concentration within a pressurized water reactor containment following a loss-of-coolant accident. The re, combiner consists essentially of a themally insulated vertical metal duct with a metal sheathed electric resistance heater provided to heat a continuous flow of containment gas mixture up to a temperatJre (ll50'F) which is sufficiently high to react the hydrogen and oxygen. The gas mixture enters the recombiner and flows up through the heater section and out the top by natural convection. No circulation fans are required and the air flow rate is established by an orifice plate at the bottom o the recombiner. The reccmbiner is designed to circulate 100 standard ft{/ min of air and has a power rating of 75 kilowatts.
Reoort WCAp-7709-L describes (1) the initial deve'lopment of the electric hydrogen recombiner (2) testing on the prototype recombiner (3) qualification testing on the production recombiner (4) long term tests on the production recombiner and (5) confirmatory tests on the production recombiner.
Staff Evaluation The results of the tests perfomed demonstrated that the Westinghouse electric hydrogen recombiner should perfom satisfactorily for the intended service condi ti ons.
One exceptien taken by the staff to the test results was the seismic test described in Section 3.3 of WCAp-7709-L Supplement 2.
Section 3.2.2 of IEEE Std 344-1971
" Trial-Use Guide for Seismic Qualification of Class I Electric Equipment for Nuclear Power Generating Stations" states "The device bair.g tested should demonstrate its ability to perfom its intended function... before, during, and following the test".
The hydrogen recombiner was not energized during the vibration test.
It was our concern that the heater eler.ents are nore likely to be subject to failure from vibraticn when they are energized because of potential tnertal stresses than when not energized.
It was not dea.onstrated that the hydrogen recombiner had the capability to perform its intended function following a seismic event, given that it had been l
energized during the event.
In response to this concern, Westinghouse provided additional infor: ation which included a seismic analysis to demonstrate the adequacy of the ele:tric hydrogen recombiner heater '
elements for seismic conditions when the recombiner is operating.
This analysis has been found to be acceptable. However, it should be noted, that acceptance of these reports does not provide generic acceptance of the ',lestinghouse vibration testing philosophy.
Whereas j
the use of the sine beat - single axis vibration testing is adequate i
for the particular items of eqaipment described in the referenced reports, other itt:ms may require different techniques.
NAY 011975
t' Neither IEEE Std 344-1971 ne-'ioned above nor IEEE Std 323-1971 " General Trial-Use Guide for Qualifyint Class i Electric Equipment for Nuclear Power Generating Stations" were referenced in WCAP-7709-L for qualifying i
the recombiner for service ir. side the containcent following a LOCA.
Ho.vever, the repdft.dces contain sufficient information to conclude its acceptability on the basis of the requirements of the above standards.
The recombiner cutlet tecperature ranges from about il50*F, a temperature sufficient for recombination, to 1450*F associated with rated sheath temperature of 1600'F.
The test temperature exceeded the recommended maximum sheath temperature for the heater elements. The maximum allowable power that resulted in a sheath temperature of 1600*F was not noted.
Westinghouse subsequently provided this power level as approximately 66Kw.
This is the uppe,r operating limit of the power suppl.y.
The power supply for the recombiner consists of a 3 phase 75 KVA trans-former, silicon-controlled rectifiers and control circuitry. The instrumentation for the recombiner is contained in a control panel and like the power supply is located outside the containment. The panel is used to control the power supply and to read out temperature from the three thermoccuples located in the recombiner. The instru-j ments counted on the panel include a power meter, thermocouple readout.
i' potentioreter, off-on switch, and power available light. The environmental limits for the control pan 21 and power supply were not stated in the original submittal.
The environmental conditions for which the power supply and control panel have been Gc,igned;were subsequently provided.
Staff Position We find that WCAP-7709-L and its. supplements provide an acceptable design and environmental and seismic qualification for the prototype and production models of the electric hydrogen recembiner.
For plants that are required to perform environmental qualification in accordance with IEEE Std. 323-1974, we shall require that the electric hydrogen recombiner also be qualified to this standard. These plants will require more documentation, than is supplied in WCAP-7709-L and its supplements, in their applications.
l We find WCAP-7820 an acceptable non-proprietary version of WCAP-7709-L.
l MAY 011975 i
I l
_ _ -