ML20140D779
| ML20140D779 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/14/1997 |
| From: | Duffy J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-97-48, NUDOCS 9704240110 | |
| Download: ML20140D779 (3) | |
Text
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VERMONT YANKEE NUCLEAR POWER CORPORATION Ferry Road, Brattleboro, VT 05301-7002 ENGINE R N OFFICE 580 MAIN STREET BOLTON. MA 01740 (508) 77H711 April 14,1997 BVY 97-48 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
References:
Attached in Enclosure A
Subject:
10CFR50.46(a)(3)(ii) Report for Vermont Yankee The purpose of this letter is to report, in accordance with 10CFR50.46(a)(3)(ii), changes in peak cladding temperature (PCT) for Vermont Yankee's Emergency Core Cooling System (ECCS)
Loss of Coolant Accident (LOCA) analysis. This analysis was performed using Yankee Atomic Electric Company's (YAEC) FROSSTEY-2/HUXY/RELAP5YA (BWR version) model, described in References (b) through (f) and approved by the NRC in References (g) through (j).
In Reference (k) Vermont Yankee reported a maximum PCT of 1801.7 F for Operating Cycle 19, our current operating cycle. Vermont Yankee has continued to refine the Cycle 19 LOCA evaluations as follows:
corrections to the unchocking logic for the critical flow calculation in RELAP5YA resulted in e
a maximum PCT of 1785.2 F, a 16.5 F decrease.
corrections to the Moody critical flow table in RELAP5YA resulted in an estimated PCT of e
i 1764.8 F, a 20.4 F decrease from 1785.2 F.
correction of the fuel performance analyses resulted in an estimated PCT of 1784.8 F, a e
20.0 F increase from 1764.8 F.
The estimated effect of these changes, taken in the aggregate, constitutes a "significant change" as defined in 10CFR50.46(a)(3)(i) and therefore is being reported in accordance with 10CFR50.46(a)(3)(ii).
We trust this information is satisfactory; however, should you have any questions, please contact this office.
y L
Sincerely, c
VERMONT YANKEE NUCLEAR POWER CORPORATION 9704240110 #70414
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VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission April 14,1997 Page 2 of 3 o
4 Enclosure A: References
't 4-c: USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS '
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VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission j
April 44.1997 Page 3 of 3
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1 ENCLOSURE A 1
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f REFERENCES
.i (a) License No. DPR-28 (Docket No. 50-271)
.(b) K. E. St. John, S. P. Schultz and R. P. Smith; Methods for the Analvsis of Oxide Fuel Rod 1
Steadv-State Thermal Effects: YAEC-1912P-A (January 1995).
(c) Report," Vermont Yankee BWR Loss-of-Coolant Accident Licensing Analysis Method, ll "YAEC-1547P-A, Revision 0, June 1986; Revision 1, July 1993.
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- (d) Report, "RELAP5YA, A Computer Program for Light-Water Reactor System Thermal-j Hydraulic Analysis," YAEC-1300P-A, Revision 0, October 1982 Revision 1, July 1993.
lf (e)' Letter, VYNPC to USNRC, "HUXY Computer Code Information for the Vermont Yankee BWR LOCA Licensing Analysis Method," FVY 87-63, dated June 4,1987.
(f) Report,;" Vermont Yankee Loss-of-Coolant Accident Analysis," YAEC-1772, June 1993..
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, (g) Letter, USNRC to VYNPC, " Approval of Use of Thermal Hydraulic Code RELAP5YA,"
NVY 87-136, dated August 25,1987.
.(h) Letter, USNRC to VYNPC, " Safety Evaluation for Vermont Yankee Nuclear Power Station, RELAP5YA LOCA Analysis Methodology," NVY 92-192, dated October 21,1992.-
(i) Letter, USNRC to VYNPC, " Vermont Yankee Nuclear Power Station, Safety Evaluation of FROSSTEY-2 Computer Code," NVY 92-178, dated September 24,1992.
-(j) Letter, USNRC to VYNPC, "HUXY Code Use," NVY 91-26, dated February 27,1991.
(k) Letter, VYNPC to USNRC, "1996 Report in Accordance with 10CFR50.46(a)(3)(ii) for Vermont Yankee," BVY 96-157, dated December 11,1996.
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