ML20132C379
Text
....,.
[
i
['
hvcloSuqG-DISTRIBUTION:
Docket File 50-412 AUG 21 g METB Docket File S.
METB Reading File WPGa. rnill Docket No. 50-412 MEMORANDUM FOR: George W. Knighton, Chief Licensing Branch No. 3, DL FROM:
William P. Gamill, Chief Meteorology and Effluent Treatment Branch, DSI
SUBJECT:
APPLICANT'S RESPONSE TO DRAFT SER OPEN ITEMS FOR BEAVER VALLEY POWER STATION, UNIT NO. 2 c-N We have reviewed the applicant's July 30, 1984 response to Outstanding Issue 115 of the subject draft SER.
This issue pertains to the adequacy of Category I structures to withstand a snow and ice load of 100 psf.
The applicant's response is a justification for using a design roof load, based on the 48-hour Probable Maximum Winter Precipitation of 72 psf, rather than addressing the ability of Category I structures to withstand a snow and ice load of 100 psf. This response is not' responsive to the issue set forth in the draft SER. Therefore, we request that the applicant be notified that their response does not resolve Outstanding Issue 115.
fitdiarilyn Ley was notified of our problem with this response during the week o FAugust 6, 1984.
Questions regarding this review should be i
directedtoE.Markee(x27635).
f-w.ter. M m sat 4 'vy
(
giinam y, twr < n William P. Gamill, Chief Meteorology and Effluent Treatment Branch Division of Systems Integration
~
cc:
D. Muller T. Novak M. Ley
, I. Spickler
- - 'E. Markee 1
l l
l
\\
6 san d XA
.n
,D,hP),T,B,,,,,DS,g,: ET,B,,,
~
ma>.9.S,1,;,RP
=>.E,$,9,r,,,,e,;,q,,,,I, Sp,1,c,k,1,e,r,,,,,,,WP,G,,, i,1,1,,,,
=>. 0. 8./.2.1./. 8.4....
.. 0. 8./.. )../.8. 4.....
.. 0. 8
../. 84.....
- ec:= sie no,eoinc ono OFFICIAL RECORD COPY
- u s a o i. n..,,,a
PLEASE NOTE: THIS 1.ETTER WAS 1551'lli 0:4 j
JULY 27, 1984 VITHOUT A LETTER Nt'.':bl'k OH o
DATE. A LETTER NUMBER AND T):l~ DAll. AKL N0k' BEING ASSIGNED TO THIS CORRESPON!W.NCl.
- /
e.
1412 s7 51 g g,,,l" f Nuclear Constreet.on D vision Robinson Pieta Building 2. svete 21o PittsDv'gh. P A 15205 July 30, 1984 United States Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Mr. George W. Knighton, Chie f Licensing Branch 3 Of fice df Nuclear Reactor Regulation
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Response to DSER Open Items Gentlemen:
This letter forwards responses to the issues listed below.
The following items are attached:
I Response to 0utstanding Issue 65 of the Beaver Valley Power Station Unit No. '2 Draf t Safety Evaluation Report.
Response to Outstanding Issue 72 of the Beaver Valley Power Station Unit No. 2 Draf t Safety Evaluation Report.
J :
Response to Outstanding Issue 115 of the Beaver valley Power Station Unit No. 2 Draft Safety Evaluation Report.
Attr.chment 4:
Response to Outstanding Issue 120 of the Beaver Valley Power j
Station Unit No. 2 Draf t Safety Evaluation Report.
DUQUESNE LIGHT COMPANY
'9 By E.(/J. Woolever Vice President KAT/wjs Attachments
.(
g4cggpogg9 840730 h p.
SUBSCRIBED AND SWOHN,TO,BEFORE ME THIS PDR ADOCK 05000412 f"// DAY OP
- t..O 1984.
A PDR
! o hod /A- $,U e L *' bQ(L 1
e n r.
Notary Public ed 0 'l S ANITA ELAINC RCITth. NOTARY PUUllC
.t f. ' 8 i8, I >,
[*I~^
f ROBINSON TOWNSHIP, ALLECHINy CCONTY dN b), I
If MY COMMIS$;ON EXPlRES OC10Btn 20,1966 I
r &
Ji4
i
.O ATTACHMENT 3 l
Response,to Outstanding Issue 115 of the Beaver Valley' Power Station Unit No. 2 Draft Safety Evaluation Report Draft SER Section 2.3.1:
Regional Climatology (excerpt)
The staff's estimate of the snowpack based on ANSI 58.1-1982, extrapo-lated fr om the 50 year return period in the standard to a 100 year return period, produces a weight of near 30 psf.
This snowpack weight,
~
when added to the weight produced by the 48-hour probable maximum vinter precipitation (about 70 psf) produces a design snowload of 100 psf.
open issue only if the design of the Category I struc-This will be an tures cannot accom:nodate a snowload of 100 ps f.
Response
The info rma t ion used to arrive at the design roof load for BVPS-2 is based on the direction given in Regulatory Guide 1.70 (R.G.
1.70),
" Standard Format and Content of Safety Analysis Reports fo r Nuclear Power Plants," Section 2.3.1.2, which states the following:
J-
" Provide estimates of the weight
- of the 100 year return period snow-pack and the weight of the 48-hour Probable Maximum Winter Precipi-tation for the site vicinity.
Using the above estimates, provide
-the weight of snow and ice on the roof of each safety-related structures."
BVPS-2 FSAR Section 2.3. 2.1 presents the weight of the 100-year return period snowpack for the site area as 19.5 lbs/f t2, developed from ANSI A58.1-1972.
'th e we igh t of the 48-hour Probable Maximum Winter Precipi-
-tetion (PMWP) is presented therein as 71.2 lbs/ft2, developed fr om
-Hydrooeteorological Report No. 33.
A design roof load of 72 lbs/f t2 was
,l chosen for safety-related structures to reflect the 48-hour PMWP as the larger of the two load estimates.
'l l
In addition to R. G.1.70, published Nuclear Regulatory Commission (NRC) guidance on the selection of snow and ic e loads for the design of roofs of safety-related structures consists of the following:
1.
10CFR50, Appendix A, General Design Criterion 2.
2.
NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," Section 2.3.1, July 1981.
3.
"American National Standard Minimum Design Loads fo r Buildings and
.i Other. Structures," ANSI A58.1-1972 (referenced in NUREG-0800).
The NRC review of this information is described in NUREG-0800, Section 2.3.1, Part III:
" Snow cnd ice locd cdaquacy is checked for reesoncbleness agains t
~
ANSI A58.1-1972 (Ref. 9) and regional data in available References 5,}6and7."
References 5, 6, and 7 are National Oceanic and Atmospheric Administra-tion. publications containing climatological data from National Weather Service stations.
The water equivalent of the 71.2 lbs/ft2, 48-hour PMWP is 13.7 inches.
Since this is far gr e at er than twice the record 24-hour pr ecipit ation tot al for any time of the year at Pittsburgh (8 inches), the use of this
. information meets the intent of the guidelines.
1 In addition, NUREU,-0800, Section 2.3.1, Part II, indicates that meteoro-logical design information is acceptable if it meets the requirements of 10CFR50, Appendix A, General Design Criterion (GDC) 2, which includes:
" Appropriate consideration of the most severe of the natural phe-nomena that have been historically reported for the site and sur-rounding area, with sufficient margin for the limited accuracy, qua nt ity, and period of time in which the historical data have been accumulated."
l The de sign snow load ofd Ibs / f t 2 based on the 48-hour PMWP is more f
l than 3.5 times the weight of the snowpack which is expected to occur l
once in 100 years based on historical data in the site area.
This load o
clearly provides "suf ficient margin for the limited accuracy, quantity.
l and period of time in which the historical data have been accumulated:
as stated in 10CFR50, Appendix A, GDC #2.
Likewise, the 48-hour PMWP i
itself meets the intent of GDC #2 by being more than 1.5 times larger than the record monthly precipitation total for any time of the year at Pittsburgh (8.2 inches).
If the more recent snow load information given in ANSI A58.1-1982 is used for..the BVPS-2 design, there is no ch ange in tne maximum load.
Based on ANSI A56.1-1982, the weight of the 100 year return period snow-pack at BVPS-2 should be approximately 30 lbs/f t2 The design value of
.72 lbs/ft2 is,still larger than this updated snowpack load (by a factor of 2.4).
Even if rain on top of the 100 year snowpack is considered,
'{
ANSI A58.1-1982 recommends adding only 5 lbs/ f t2, resulting in a tot al 1
weight of 35 lbs/ft2 The design snow load would be equalled only if l
the record monthly precipitation total for Pittsburgh for any time of the year (8.2 inches) were assumed to be completely absorbed by the 100-year return period snowpack -(30 lbs/ft2 or approximately 6 inch es of water) without melting or runof f.
Therefore, the BVPS-2 design snow load clearly meets the intent of NRC regulations.
-C t
l 6
-