ML20012F160
| ML20012F160 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/29/1990 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-68524, ULNRC-2182, NUDOCS 9004100237 | |
| Download: ML20012F160 (7) | |
Text
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U.S. Nuclear Regulatory Commission Attn Document Control Desk
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Mail Stop P1-137 l
Washington, D.C. 20555 Gentlemen ULNRC-2182 a
DOCKET NUMBER 50-483 CALLAWAY PLANT STATION BLACKOUT
_NRC T&C Ho._ 6812_4_,..
References:
- 1) ULNRC-1973, dated April 12, 1989
- 2) NUMARC 87-00 Supplemental Questions / Answers, dated December 27, 1989 i
- 3) NUMARC 87-00 Major Assumptions, i
i dated December 27, 1989 This letter supplemente the referenced Union Electric response to the Station Blackout Rule, i
10CFR50.63, and is being provided in accordance with recent NUMARC guidance intended to assure consistent implementation of NUMARC 87-00,
" Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout At Light Water Reactors".
NUMARC has requested that each utility review its SB0 response and supporting documentation in light of concerns identified by the NRC during the initial audits of utility responses.
Specifically, utilities have been asked to verify that:
1.
Implementation is consistent with the supplemental guidance provided by
(
References 2 and 3, 2.
The applicability of NUMARC 87-00 assumptions is documented in utility files, and 3.
Departures from the accepted NUMARC 87-00 methodology are identified.
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NUMARC has additionally requested that each utility supplement its previous SBO submittal to the NRC with a letter which provides the results of the above review and which affirms that the selected diesel generator target reliability will be maintained.
J Accordingly, Union Electric hab reviewed our original submittal and supporting documentation I
against the guidance of NUMARC 87-00, including l
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the clarifications in References 2 and 3..
We have i
l concluded that the validity of NUMARC 87-00 assumptions are adequately documented and that the l
evaluation performed is consistent with the intent of the NUMARC 87-00 guidance.
Departures from 6
l specific NUMARC 87-00 methodology are summarized as follows:
I 1.
Reference 1 states that an inventory of 158,000 gallons of condensate is required for decay heat removal during an SBO of four-hour duration.
This i
value was determined using a Callaway-specific analysis which incorporates the methodology for calculating decay l
heat originally employed by callaway a NSSS supplier.
Calculations have been performed to demonstrate that the l
Callaway-specific methodology produces a E
more conservative value for required condensate inventory than does the NUMARC 87-00 methodology.
l 2.
References 2 and 3 state that only poured concrete walls may be used as l
heat sinks in room heat-up calculations using the NUMARC 87-00 methodology.
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Walls constructed of fully grouted, ASTM C90, concrete masonry unite were used as i
heat sinks in room heat-up calculations for Callaway's Battery and DC i
Switchboard rooms.
The acceptability of using these walls as heat sinks has been conservatively demonstrated in I-calculations and is consistent with the 1989 ASHRAE Fundamentals Handbook which i
states that thermal properties for fully l
grcuted block may be approximated using values for poured concrete.
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3.
The NUMARC 87-00 room heat-up methodology is not applicable to the l
configuration of the Callaway control room and was therefore not used to j
calculate its steady state temperature.
l The control room temperature was determined using an alternate method which is based on heat transfer due to temperature gradients across the ceiling, walls, and floor and which L
considers the thermal resistance values for the building materials involved.
Use of this alternate method precludes l
the concerns noted in References 2 and 3 regarding misapplication of the NUMARC room heat-up methodology, l
4.
Rather than estimating heat generation rates for steam-driven equipment using l
NUMARC 87-00 methodology, Callaway-t specific data was used for the turbine and piping in the turbine driven auxiliary feedwater pump room.
The heat
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gain from the turbine was determined using heat rejection values provided by i
the turbine manufacturer and the heat gain from piping was determined using the design-maximum heat transfer rate at i
the insulation's outer surface.
l 5.
Valves ENHV0001, ENHV0007, EJHV8811A, and EJHV8811B are containment recirculation sump isolation valves i
i contained within encapsulations which i
are an extension of the containment boundary.
Because plant operation at power with these valves in the open i
position is a violation of Technical Specifications, these valves are excluded from consideration as containment isolation valves requiring f
i manual closure capability during an SBO.
6.
The NUMARC 87-00 operating procedure L
guidelines recommend opening doors to h
control room cabinets containing safe
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shutdown instrumentation within 30 r
minutes from the onset of an SBO.
Callaway Plant Procedure OTO-GK-00001, l
Loss of Control Room HVAC with High I
Control Room Temperature, requires that cabinet doors be opened when Control Room temperatures approach 90 degrees l
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ff[ 3, Fahrenheit.
This approach is consistent f
with the NUMARC 87-00 basis for this recommendation, which states that i
actions necessary to ensure that equipment failure does not occur as a result of a loss of ventilation should
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be tied to either the actual loss of AC l
power or upon reaching certain temperatures in the plant, j
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With regard to the issue of Emergency Diesel
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Generator (EDG) target reliability, Callaway will j
comply with NUMARC SB0 Initiative 5A, which ham
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L been revised to address EDG performance, including l
maintenance of the selected target reliability.
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l Very truly yours, t.
4xht Donald F. Schnell
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Alan C. Passwater, of lawful age, being first duly sworn upon oath says that he is Manager, Licensing and Fuels (Nuclear) for Union Electric Company; that he has read the foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and that the facts therein stated are true and correct to the best of his i
l knowledge, information and belief.
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j Alan C. Passwater Manager, Licensing and Fuels Nuclear 2N SUBSCRIBED and sworn to before me this day of
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l' cci Gerald Charnoff, Esq.
Shaw, Pittman, Potts & Trowbridge 2300 N. Street, N.W.
Washington, D.C. 20037 Dr. J. O. Cermak CFA, Inc.
l 4 Professional Drive (suite 110)
Gaithersburg, MD 20879 R. C. Knop chief, Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region !!!
799 Roosevelt Road i
Olen Ellyn, Illinois 60137 Bruce Little callaway Resident Office U.S. Nuclear Regulatory Commission RR#1 Stoodman, Missouri 65077 S. V. Athavale (2)
Office of Nuclear Reactor Regulation f
U.S. Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 Manager, Electric Department Missouri Public Service Commission P.O. Box 360 l
Jefferson City, MO 65102 I
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