ML20064E526
| ML20064E526 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/29/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20064E525 | List: |
| References | |
| NUDOCS 8301060042 | |
| Download: ML20064E526 (2) | |
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Q SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 24 TO FACILITY OPERATING LICENSE OPR-77 TENNESSEE VALLEY AUTHORITY INTRODUCTION The operating license of Sequoyah Unit 1 contains a condition requiring that prior to startup, following the first refueling outage, the Commission must confirm that an adequate hydrogen control system for the plant is installed and will perfom its intended function in a manner that provides adequate safety nargins.
The Commis-sion met on December 15, 1932, and affirmed that the system now being installed in Unit 1 meets the license condition, subject to the satisfactory resolution of two items as proposed by the staff.
These two items are the subject of this amendment.
Also, TVA proposed in their letter of September 17, 1982, a Technical Sg-ification revision for the hydrogen systen being installed in Unit 1.
Further revisions were provided in a TVA letter of December 23, 1982.
DISCUSSIOQ Supplement No. 6 to the SER provides the basis for the staff's conclusion and the Cmmission affirming that the TVA Permanent Hydrogen Hitigation System now being installed in Unit 1 is adequate, subject to meeting two new license conditions.
Specifically, these conditions concern the capability of the Tayco igniter to main-tain (1) a surface temperature sufficient to initiate combustion in a spray environ-ment and (2) the density of the igniters in the upper containment to ensure favor-able consequences of the hydrogen burns in the upper compartment.
Recent tests conducted by TVA indicate that the igniters will function as intended.
- However, the temperature margin provided by the igniters as shown in the TVA tests, appears to be small under spray conditions.
The staff initially proposed a set of tests directed toward assuring adequate surface temperature under spray conditions.
However, on subsequent consideration the staff proposed that such tests not be limited to igniter temperature but should demonstrate capability to initiate com-l bustion under spray conditions.
The staff will require that TVA complete cer-tain additional ignition tests to verify that the Tayco igniter will function prop-erly in a spray environment such as that expected in the upper compartment of the ice condenser containment.
Also, the staff is requiring the installation of four additional igniters in the upper capartment at locations satisfactory to the staff.
The instal'3 tion of additional igniters in the upper compartment will provide a greater margin of safety.
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. 4 Also, TVA proposed some changes to the Technical Specifications to reflect the changes associated with the new hydrogen nitigation systen.
The new system is com-posed of 32 igniters in each of two trains.
At a later date each train will be increased by 2 igniters. Surveillance requirenent 4.6.4.3(a) is acceptable to the staff, since the procedures require energizing the igniters once per 92 days.
A train is inoperable if more than one igniter fails to energize.
Surveillance re 'uirement 4.6.4.3(b), however, was not acceptable as proposed by TVA, since vr ifying that the igniter were clean every 18-months would not ensure operability.
In discussions with the licensee, the staff indicated its belief that at least one per 18 nonths the tenperature of each igniter should be verified to be at a minimua of 1700 F.
TVA letter of December 23, 1932, accepted the staff's position until each time as the additional igniter tests results may change the operational temper-ature.
The Technical Specification was modified to reflect the staff's position and the agreement of the licensee.
ENVIR0tiMENTAL CONSIDERATION We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any signif-icant environmental impact.
Itaving made this determination, we have further con-cluded that the amendment involves an action which is insignificant from the stand-point of environmental impact and, pursuant to 10 CFR SSI.5(d)(4), that an environ-mental impact statement or negative declaration and envirstmental impact appraisal need not be prepared in connection with the issuance of this amendment.
CONCLllSION We have concluded, based on the considerations discussed above, that: (1) because the amendment does not involve a significant increase in the probability or con-sequences of accidents previously considered, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant hazards consideration (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Comnission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
i Date:
December 29, 1982 Principal Contributor: Carl Stable, Licensing Branch No. 4, DL i
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