ML20033G513
| ML20033G513 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 03/30/1990 |
| From: | Rhodes F WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ET-90-0057, ET-90-57, TAC-68628, NUDOCS 9004100149 | |
| Download: ML20033G513 (2) | |
Text
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W4) NUCLEAR OPERATING C LF CREEK P on.ei t smose.
I.,@weemew March 30, 1990 RT 90 0057 U. S. Nuclear Regulatory Coeur.ission ATTH: Document Cor, trol Desk Mail Station Pl.137 Washington, D. C. 20555
Reference:
- 1) Letter dated April 17, 1989 from J. As Bailey, WCNOC to the NRC
- 2) Letter dated January 4, 1990 from B. Lee, Jr.,
NUMARC to the NUMARC Board of Directors subject:
Docket No. 50 482:
Supplemental Response to Station Blackout Rule (NRC TAC No. 68628)
Gentlemen Attached is Volf Creek Nuclear Operating Corporation's (WCN00) supplemental response to the Station Blackout Rule as required by Reference 2.
Reference 2 requested that utilities review their responses (Reference 1) ta the Station Blackout Rule to address NRC concerns regarding $50 rule responses and implementation of guidance contained in NUMARC 87 00,
' Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout in Light Water Reactors'.
WCN00 has reviewed keference 1 and supporting documentation.
This review has detennined that Reference 1 was based on utilisation of the NUMARC 87 00 guidance including the clarifications in Reference 2.
accepted NUMARC 87 00 guidance was indicated in Reference 1.A deviation from the During this review additional deviations from the NUMARC 67 00 guidance were identified, these items are discussed in the attachment to this letter.
As stipulated in Reference 1 WCNOC has chosen 0.95 as its emergency diesel generator target reliability.
value.
WCNOC intends to maintain this target reliability If you have any questions concerning this matter, please contact me or Mr. O. L. Maynard of my staff Very truly yours, b[ 'h).h NbhK t
FN Forrest T. Rhodes Vice President Engineering & Technical Services Attachment cca R. D. Martin (NRC), w/a D. Persinko (NRC), w/a I
D. V. Pickett (NRC), w/a I
M. E. Skow (NRC), w/a
(
PO. Ikm 411 I Bu*ngeorg, KS 6643s / Phone: (316) 364 sB31 M fW Oppatey Drv*yer tuMT
_j
Attachment to ET 90 0057 Page 1 cf 1 l
Suppleasental Response to Station Blackout Rule l
Identified below are additional deviations from the accepted NtMARC 87-00 methodology.
The detailed analyses and related information are maintained at i
the Wolf Creek Generating Station and are available for NRC review.
The items are numbered consistent with the generic response format utilised in Reference 1.
I 4.
Effects of Loss of Voytilation (section 7.2.4)
I a.
Auxiliary Feedwater Pump Room The calculation for heat transmission into the room from the three high energy pipes was based on the restriction of heat flow due to j
insulation.
A value was used of twice the maximum heat loss allowed by i
j the insulation design specification.
This method provides a more realistic result (lower temperature) than the NtMARC 87 00 methodology, 1
but is still conservative as it predicts a temperature buildup higher than actually experienced during preoperational testing, b.
Control Room Complex The methodology explained in Appendix E of NIMARC 87 00 assumed that the temperature of the room in question is equal to or higher than the surrounding area temperatures.
Ths heat transfer through the ceiling, floor and walls due to increasing temperature gradients across these barriers is conservatively neglected.
As the Control Room is normally I
kept significantly cooler than the surrounding areas, the heat transfer due to temperature gradients during the early portion of the station blackout event cannot be conservatively neglected.
As a result, the heat transmission was determined using a methodology I
similar to that of Chapter 23 of the 1981 American Society of Heating, l
Refrigerating and Air. Conditioning Engineers Inc. (ASHRAE) Fundamentals Handbook.
The calculation essentially modeled the Control Room Complex i
as a box.
The outcome is conservative as conduits and other i
penetrations transfer heat out of the room.
The heat up of air, valls, floor, ceiling, as well as the upper and lower cable spreading rooms was modeled with respect to time. The steady state control room temperature was determined using design maximum summer conditions.
This led to additional conservatism in the analysis.
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