ML20196F511
| ML20196F511 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 12/01/1998 |
| From: | Alexion T NRC (Affiliation Not Assigned) |
| To: | Cottle W HOUSTON LIGHTING & POWER CO. |
| References | |
| TAC-MA3763, TAC-MA3764, NUDOCS 9812070055 | |
| Download: ML20196F511 (5) | |
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UNITED STATES g
j NUCLEAR REGULATORY COMMISSION i
I WASHINGTON, D.C. Samaa "I
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l December 1, 1998 l
Mr. William T. Cottle President and Chief Executive Officer i
STP Nuclear Operating Company South Texas Project Electric Generating Station i
P. O. Box 289 Wadsworth,TX 77483 l
SUBJECT:
UPDATE TO TECHNICAL SPECIFICATION BASES SECTION 3/4.9.10 AND 3/4.9.11, SOUTH TEXAS PROJECT (STP), UNITS 1 AND 2 (TAC NOS.
MA3763 AND MA3764)
Dear Mr. Cottle:
The purpose of the letter is to respond to South Texas Project's (STP) September 30 and November 3,1998, letters which provided an update to Technical Specification (TS) Bases Section 3/4.9.10 and 3/4.9.11, " Water Level-Refueling Cavity and Storage Pools." The specific change removes the 10% value for clad gap iodine isotopics. The letter did not request any approval or response from the Nuclear Regulatory Commission (NRC). However, this letter is provided to confirm that NRC agrees with the proposed change.
The bases section states that the restrictions on the minimum water level is to ensure that sufficient water depth is available to remove 99% of the iodine gap activity released from the rupture of an irradiated fuel assembly. Stating the percentage of iodine present in the gap has no impact on the basis for the specification.
l The amount of iodine present in the gap is captured in the accident analysis source term. This information is part of the STP Upated Final Safety Analysis Report, Chapter 15.7.4.2.2, Assumptions for the Fuel Handling Accident in the Reactor Containment Building. Based on a previous change in fuel enrichment, the gas gap consists of 10% of the fuel assembly inventory of iodides, except 1-131 which is 12%.
The NRC staf' agrees with the proposed change to remove the 10% value for the clad gap iodine isotopas since it does not provide a basis for this specification and the information is contained in the UFSAR where any past or future changes are controlled under 10 CFR 50.59.
Enclosed for your information, is revised TS Bases page B 3/4 9-3 that the NRC staff will use to i
update NRC's copy of the Bases. The revised page contains marginallines indicating the areas l
1 0812070055 981201
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l Mr. William T. Cottle 2
of change. The corresponding overleaf page is also provided to maintain document completeness. If you have any additional questions regarding this issue, please contact me at (301) 415-1326.
Sincerely, uN Thomas W. Alexion, Project Manager Project Directorate IV-1 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
Bases Page B 3/4 9-3 cc w/ encl: See next page
1 Mr. William T. Cottle 2
of change. The corresponding overleaf page is also provided to maintain document completeness. If you have any additional questions regarding this issue, please contact me at (301)415-1326.
Sincerely, ORICINAL SIGNED BY:-
Thomas W. Alexion, Project Manager Project Directorate IV-1 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
Bases Page B 3/4 9-3 cc w/encls: See next page DjSTRIBUTION:
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PD/PD4-1 NAME MGambi/vw TA e)
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Mr. William T. Cottle STP Nuclear Operating Company South Texas, Units 1 & 2 cc:
l Mr. Cornelius F. O'Keefe Jack R. Newman, Esq.
Senior Resident inspector Morgan, Lewis & Bockius U.S. Nuclear Regulatory Commission 1800 M Street, N.W.
P. O. Box 910 Washington, DC 20036-5869 l
Bay City, TX 77414 Mr. Lawrence E. Martin A. Ramirez/C. M. Canady Vice President, Nuc. Assurance & Licensing j
City of Austin STP Nuclear Operating Company Electric Utility Department P. O. Box 289 i
721 Barton Springs Road Wadsworth,TX 77483 Austin, TX 78704 Office of the Governor Mr. M. T. Hardt ATTN: John Howard, Director Mr. W. C. Gunst Environmental and Natural City Public Service Board Resources Policy P. O. Box 1771 P. O. Box 12428 i
San Antonio,TX 78296 Austin, TX 78711 Mr. G. E. Vaughn/C. A. Johnson Jon C. Wood Central Power and Light Company Matthews & Branscomb P. O. Box 289 One Alamo Center Mail Code: N5012 106 S. St. Mary's Street, Suite 700 Wadsworth,TX 74483 San Antonio, TX 78205-3692 l
INPO Arthur C. Tate, Director Records Center Division of Compliance & Inspection l
700 Galleria Parkway Bureau of Radiation Control Atlanta, GA 30339-3064 Texas Department of Health 1100 West 49th Street Regional Administrator, Region IV Austin,TX 78756 i
l U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Jim Calloway Arlington, TX 76011 Public Utility Commission of Texas Electric Industry Analysis l
D. G. Tees /R. L. Balcom P. O. Box 13326 Houston Lighting & Power Co.
Austin, TX 78711-3326 P. O. Box 1700 Houston,TX 77251 l
l Judge, Matagorda County Matagorda County Courthouse 1700 Seventh Street Bay City, TX 77414 4
REFUELING OPERATIONS BASES 3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLAffr CIRCULATION ne requirement that at least one residual heat removal (RHR) loop be in operation ensures that: (1) sufficient cooling capacity is available to remove decay heat and maintain the l
water in the reactor vessel below 140'F as required during the REFUELING MODE, and (2) l sufficient coolant circulation is maintained thmy;h the core to minimim the effect of a boron dilution incident and prevent boron stratification.
He requirement to have two RHR loops OPERABLE when there is less than 23 feet of water above the reactor vessel flange ensures that a single failure of the operating RHR loop will not result in a complete loss of residual heat removal capability. With the reactor vessel head removed and at least 23 feet of water above the reactor pressure vessel flange, a large heat sink is available for core cooling. Thus, in the event of a failure of the operating RHR loop, adequate time is provided to initiate emergency procedures to cool the core.
3/4.9.9 CONTATNMENT VENTILATION ISOLATION SYSTEM The OPERABILITY of this system ensures that the containment purge and exhaust penetrations will be automatically isolated upon detection of high radiation levels in the purge
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exhaust. The OPERABILITY of this system is required to restrict the release of radioactive material from the containment atmosphere to the environment.
3/4.9.10 and 3/4.9.11 WATER LEVEL-REFUELING CAVITY AND STORAGE POOLS The restrictions on minimum water level ensure that sufficient water depth is available to remove 99% of the assumed iodine gap activity released from the rupture of an irradiated fuel l
assembly. The minimum water depth is consistent with the assumptions of the safety analysis.
3/4.9.12 FUEL HANDLING BUILDING EXHAUST AIR SYSTEM e
ne limitations on the Fuel Handling Building Exhaust Air System ensure that all radioactive material released from an irradiated fuel assembly will be filtered through the HEPA filters and charcoal adsorber prior to discharge to the atmosphere. Operation of the system with the heaters operating for at least 10 continuous hours in a 31-day period is sufficient to reduce the buildup of moisture on the adsorbers and HEPA filters. The OPERABILITY of this system and the resulting iodine removal capacity are consistent with the assumptions of the safety analyses.
ANSI N510-1980 will be used as a procedural guide for surveillance testing. This Specification has been modified by a note that states, at least one FHB exhaust air filter train, one FHB exhaust booster fan, and one FHB main exhaust fan are capable of being powered from an Onsite emergency power source. His note ensures that required FHB exhaust train components will have an emergency power source available, even if the limiting conditions for operation can be satisfied.
SOUTH'IEXAS - UNITS 1 & 2 B 3/4 9-3 Unit 1 - Ama== No. 69rH Unit 2 - A=wht No. 68r60 Revised by letter dated: 12/01/98
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