BVY-96-157, Submits Changes in Peak Cladding Temp for Plant ECCS LOCA Analysis
| ML20132B998 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 12/11/1996 |
| From: | Duffy J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-96-157, NUDOCS 9612180062 | |
| Download: ML20132B998 (3) | |
Text
oVi!iRMONT. YANKEE NUCLEAR POWER CORPORATION Ferry Road, Brattleboro, VT 05301-7002 s
~
ENGINE R N OFFICE N'
580 MAIN STREET BOLTON. MA 01740 (508) 77H711 December 11,1996 BVY 96-157 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-
References:
Attached in Enclosure A
Subject:
199610CFR50.46(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 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 1778.1 F for Operating Cycle
- 18. During Cycle 18, LOCA evaluations were performed to assess the effect of each of the following changes:
Revised instrument uncertainty on the ECCS low pressure permissive setpoint which resulted in a maximum PCT of 1780.5 F, a 2.4 F increase.
Revised Recirculation pump discharge bypass valves position modelling which resulted in a maximum PCT of 1764.5 F, a 13.6 F reduction.
Revised RHR minimum flow bypass valves modelling which resulted in a maximum PCT of
/
1793.9 F, a 15.8 F increase (Reference (l)].
/
,+ 0 o j These changes, taken singly or in the aggregate, did not constitute a "significant change" as defined in 10CFR50.46(a)(3)(i) and therefore were not previously reported.
The Cycle 19 calculations are described in YAEC-1935, " Vermont Yankee Cycle 19 Core Performance Analysis Report," which was provided to the NRC in Reference (m). For Cycle 19, the three changes described above, as well as a reduction in Core Spray system flow rate and cycle-specific changes in stored energy, scram reactivity and fuel conductivity for the higher-enriched GE-98 bundle type, were incorporated into the reload analysis evaluation model.
These changes resulted in a maximum Cycle 19 PCT of 1801.7 F,23.6 F higher than the Cycle 18 PCT reported in Reference (k).
9612180062 961211 PDR ADOCK 05000271 P
P
+.
e VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission l
December 11,1996 Page 2 of 2
.i i
t F
We trust this information is satisfactory; however, should you have any questions, please do not hesitate to contact us.
k Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION fllIlf4 2
James J. Duffy l
Licensing Engineer Enclosure A: References 1
7 n
I c:
USNRC Region 1 Administrator l
USNRC Resident inspector -VYNPS USNRC Project Manager - VYNPS i
o 4
P l
i i
I d' '
- VERMONT YANKEE NUCLEAR POWER CORPORATION.
e ENCLOSURE A REFERENCES (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 j
. Steadv-State Thermal Effects; YAEC-1912P-A (January 1995).
l.
(c) Report, " Vermont Yankee BWR Loss-of-Coolant Accident Licensing Analysis Method, "YAEC-1547P-A, Revision 0, June 1986; Revision 1, July 1993.
]
l (d) Report, "RELAP5YA, A Computer Program for Light-Water Reactor System Thermal-l Hydraulic Analysis," YAEC-1300P-A, Revision 0, October 1982 Revision 1, July 1993.
(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, i
(f) Report, " Vermont Yankee Loss-of-Coolant Accident Analysis," YAEC-1772, June 1993.
j (g) Letter, USNRC to VYNPC, " Approval of Use of Thermal Hydraulic Code RELAP5YA,"
NVY 87-136, dated August 25,1987.
l (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 j
FROSSTEY-2 Computer Code," NVY 92-178, dated September 24,1992.
i (j) Letter, USNRC to VYNPC, "HUXY Code Use," NVY 91-26, dated February 27,1991.
-(k) Letter, VYNPC to USNRC, "1995 Report in Accordance with 10CFR50.46(a)(3)(ii) for Vermont Yankee," BVY 95-141, dated December 29,1995.
1 (1) Letter, USNRC to VYNPC, " Vermont Yankee Special inspection Report 50-271/96-07," NVY 96-118, dated July 2,1996 i
i (m) Letter, VYNPC to USNRC, " Vermont Yankee Cycle 19 Core Operating Limits Report," BVY 96-129, dated October 21,1996 i
l I
l-4 L
4
.