ML20056C453
| ML20056C453 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/18/1993 |
| From: | Feigenbaum T TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-93090, NUDOCS 9306240144 | |
| Download: ML20056C453 (5) | |
Text
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.e-s Seab k NH 03874 Telephone (603)474 9521 i
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Facsimile (603)474-2987 Energy Service Corporation Ted C. Feigenbaum Senior Vice President and -
Chief NuclearOfficer NYN-93090 -
June 18,1993 United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Document Control Desk
Reference:
Facility Operating License No. NPF-86, Docket No. 50-443
Subject:
10CFR50.46 Annual Report Gentlemen:
North Atlantic Energy Service Corporation (North Atlantic) has enclosed herein, pursuant to 10CFR50.46(a)(3), the 1993 Annual Report of Emergency Core Cooling System (ECCS) Evaluation Model Revisions. The enclosure includes a tabulation of the limiting Large Break LOCA and limiting Small Break LOCA Peak Cladding Temperature (PCT) margin allocations applicable to Seabrook Station. The PCT margin allocations reported in the enclosure represent permanent PCT margin allocations attributable to ECCS evaluation model revisions and plant specific input assumption revisions through the period of January 21, 1993 as reported to North Atlantic by Westinghouse on January 25, 1993.
North Atlantic notes that the PCT margin allocations reported herein include'the PCT increases associated with the elimination of the RTD Bypass System which was proposed in License Amendment Request 92-01 and Supplement I thereto on June 19,1992 and approved by the NRC on August 10,1992 (Ref. Amendment 12 to Facility Operating License NPF 86).
The modified Reactor Coolant System (RCS) temperature measurement system design yields-an increase in the uncertainty value for RCS average temperature from 4 'F t o.
5 *F.
The attendant PCT increases are 4 *F for the large break LOCA and 8 *F for the small break L O C A~.
. The PCT margin allocations. reported herein also ' include the ' PCT increases -
associated with the relaxation in the Pressurizer Safety Valve and Main Steam Safety Valve setpoints tolerances to 3% which was proposed in License Amendment ' Request 92-11 g
dated May 5,1992 and approved by the NRC on September 3,1992 (Ref. Amendment 15 to
' Facility Operating License. NPF 86).' The attendant PCT increase reported herein is 5 *F for the small break LOCA only. The large break LOCA analysis r'esults were not affected by the setpoint tolerance relaxation. The current PCT values reported herein are 2054.2 *F for the large break LOCA and 1986.2 *F for the small break LOCA.
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9306240144 930618 3, member of the Northeast Utilities system DR-ADOCK 0500 3
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United States Nuclear Regulatory Commission June 18,1993 Attention:'
Document Control Desk
. Page two The' enclosure demonstrates North Atlantic's compliance with the requirements of 10CFR50.46 and thus no additional analyses or further actions are required. Should you have any questions regarding this letter, please contact Mr. James M. Peschel, Regulatory Compliance Manager at (603) 474 9521 extension 3772.
Very truly yours, Ted C. Feigenbaum-TCF:.A LL/act/t ad Enclosure cc:
Mr. Thomas T. Martin Regional Administrator U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Mr. Albert W. De Agazio, Sr. Project Manager Project Directorate I-4 Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, DC. 20555 Mr. Noel Dudley NRC Senior Resident Inspector P.O. Box 1149 Seabrook, NII 03874 c
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North Atlantic June 18,1993 ENCLOSURE TO NYN-93090 f~
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ECCS EVALUATION MODEL REVISIONS 10CFR50.46 ANNUAL REPORT 1993 PEAK CLAD TEMPERATURE (PCT) MARGIN ALLOCATION LARGE BREAK LOCA A.
Analysis of Record PCT =
- 1965.2 'F -
(Updated Final Safety Analysis Report,
'l Rev.1, May 1992, Sec.15.6*)
J B.
ECCS Evaluation Model Revisions
]
(thru 1/93 as reported in Westinghouse letters dated 6/20/91,6/23/92 and 1/25/93) a.
Fuel Rod Initial Conditions A PCT =
+ 25.0 *F Inconsistency b.
Steam Generator A PCT =
+ 40.0 'F ~
Seismic /LOCA Assumption c.
Containment Purge A PCT =
+ 1.0
- F d.
Containment Ili-1 Pressure A PCT -
+ 1.0 'F Setpoint Increase C.
Plant Specific Input Assumption Revisions a.
Chamfered Pellet A PCT =
+ 10.0
- F b.
Tube Plugging A PCT =
+ 8.0 'F *
- c.
RTD Bypass Elimination A PCT =
+ 4.0 'F' "
Analysis of Record PCT + A PCT Marcin Allocation = 2054.2 'F The Large Break LOCA analysis was performed utilizing the February 1978 version l
of the Westinghouse Large Break Evaluation'Model, t
The 1991 10CFR50.46 Annual' Report specified a 1 'F PCT margin allocation for-steam generator tube - plugging based - on. the number of tubes plugged in' the -
as shipped steam generators for Unit 1. Currently, less than.25% of the tubes are plugged.in the steam generator with maximum plugging. Westinghouse allocated 8 'F for each 1% of steam generator tubes plugged. For conservatism,- 8 *F is reported herein.
License Amendment Request 92 01' and Supplement 1 thereto. dated: June 19,1992 l proposed Seabrook Station Technical Specification changes relating to.the proposed climination of the RTD. Bypass System. The changes were approved by the NRC on August 10,1992 (Ref. Amendment 12.to Facility Operating License NPF-86). The Reactor Coolant System temperature measurement system uncertainty value for Reactor Coolant System average temperature increases from 4 'F to i 5 'F.
The-attendant increase in PCT is reported herein.
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1 ECCS EVALUATION MODEL REVISIONS -
10CFR50.46 ANNUAL REPORT 1993 PEAK CLAD TEMPERATURE (PCT) MARGIN ALLOCATION SMALL BREAK LOCA A.
Analysis of Record
. PCT =
1790.0 'F (Updated Final Safety Analysis Report, Rev.1, May 1992, Sec.15.6*)
B.
ECCS Evaluation Model Revisions (thru 1/93 as reported in. Westinghouse letters dated 6/20/91,6/23/92 and 1/25/93) a.
Fuel Rod Initial Conditions A PCT =
+ 37.0 'F -
Inconsistency C.
Plant Specific Input Assumption Revisions a.
Chamfered Pellet A PCT =
+ 10.0 'F b.
+ 136.2 *F Enthalpy Switchover c.
RTD Bypass Elimination A PCT =
+ 8.0 *F*
- d.
PSV/MSSV Setpoint Tolerance A PCT =
+ 5.0. *F"
The Small Break LOCA analysis was performed utilizing the October 1975 version of the Westinghouse ECCS Small Break Evaluation Model.
License Amendment Request 92-01 and Supplement 1 thereto dated June 19, 1992.
proposed Seabrook Station Technical Specification changes relating to the proposed climination of the RTD Bypass System. The changes were approved by the NRC on -
August 10,1992 (Ref. Amendment 12 to Facility Operating License NPF-86). The proposed Reactor Coolant System temperature measurement system uncertainty value y for Reactor Coolant System' average temperature increases from 4 'F to
-5 *F.
The attendant increase in PCT is reported herein.
License. Amendment Request 92-11 dated May 5,1992 proposed Seabrook Station -
Technical Specification changes relating to the proposed relaxation in the Pressurizer Safety Valve and Main Steam Safety Valve setpoints tolerances to. t 3E The changes were approved by the NRC on September -3,1992 (Ref. Amendment 15 to Facility Operating License NPF-86). The attendant FCT increase reported herein is 5 'F for the small break LOCA only The large break LOCA analysis results were not '
affected by the setpoint tolerance relaxation.
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