ML20076K225
| ML20076K225 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/17/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20076K221 | List: |
| References | |
| NUDOCS 9410270325 | |
| Download: ML20076K225 (3) | |
Text
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d UNITED STATES l,
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NUCLEAR REGULATORY COMMISSION g
WASHINGTON, D.C. 20555-0001 f~
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.188 TO FACILITY OPERATING LICENSE NO. DPR-77 AND AMENDMENT NO.180 TO FACILITY OPERATING LICENSE NO. DPR-79 TENNESSEE VALLEY AUTHORITY SE000YAH NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328
1.0 INTRODUCTION
By application dated August 19, 1994, the Tennessee Valley Authority (TVA or the licensee) proposed amendments to delay the implementation dates specified in Amendment Nos. 182 and 174 for Units 1 and 2 respectively, to fiscal year 1995.
The amendments issued on May 24, 1994, were in response to the licensee's aoplication dated October 1, 1993 which required that the changes for each unit be implemented during the Unit 2 Cycle 6 refueling outage.
The licensee has since determined that implementation should be delayed.
No changes to the Technical Specification pages that were issued with Amendment Nos. 182 and 174 are involved with this change.
The pu pose of Amendment Nos.182 " r " nit 1) and 174 (for Unit 2) is to revise th-setpoints and time del y; f.
- t. 3 auxiliary feeowat - (AFW) loss of power and 6.9 kv shutdown board loss-of-voitage and degraded-voltage instrumentation.
These changes would also revise the description, tot _.
number of channels, channels to trip, minimum channels operable, actions, trip setpoints, allowable values, channel checks, and channel functional test requirements for loss-of-power instrumentation.
The loss-of-voltage and degraded-voltage protection are provided to the 6900-volt shutdown boards to ensure that adequate voltage is available to the i
safety-related loads.
A loss-of-voltage or a sustained degraded-voltage condition will start the emergency diesel generator (EDG) that will be connected to the shutdown board after tripping the normal and alternate feeders and shedding the major loads.
After the EDG has been tied to the shutdown board, the loss-of-voltage relays continue to provide the load-shed i
l functions and subsequent resequencing of the loads onto the EDG if necessary.
I l
After the EDG has connected to the shutdown board and the load sequencing interval has been achie md, the loss-of-voltage load-shed feature of the i
1 6.9 kv shutdown board initiates a motor-driven AFW pump start.
In addition, ENCLOSURE 3 9410270325 941017 ADOCK0500g7 PDR P
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- the load-shed actuation immediately activates a turbine-driven AFW pump start.
The reactor coolant pumps would not be available to provide forced coolant flow in the event of loss of voltage, but the turbine-driven AFW pumps start 1
to initiate natural circulation and heat removal in the reactor coolant system via the steam generators.
The AFW pumps provide sufficient heat-removal capability to prevent the pressurizer from filling during design-basis accidents.
In its application for the amendments to implement this design change, the licensee indicated that the modifications to both Units 1 and 2 are necessary to implement the design change and the TS amendments would be accomplished i
during the Unit 2 Cycle 6 refueling outage.
This schedule was reflected in Amendment Nos. 182 and 174 when they were approved by the Commission on May 24, 1994.
Subsequently, by letter dated August 19, 1994, the licensee submitted an amendment requesting that implementation of these amendments be delayed until the related plant modifications are executed during fiscal year 1995.
The exact timing will depend on the preparation of appropriate staging and completion of detailed evaluations related to the modification.
The licensee explained that during the present Unit 2 Cycle 6 refueling outage, which started on July 4,1994, the plant modifications were to be performed in two stages so they could be completed within the action limits of TS 3.8.1.1 for Unit I that is in power operation.
This led to the determination that the additional number of temporary wire terminations and jumpers required for the staged process would increase the risk of exceeding the TS action limit of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
This concern, along with additional testing and partial modification configurations that the operators would have to contend with while 'he plant changes are being m le, aused the licensee to reevaluate the best condi;ic 3 for implementation cf t _
unges.
The result was a decision to move the mudification outside the re ueling outage, and into the period when both units would be in power operation in fiscal year 1995.
TVA considers performance of the modifications during power operation acceptable because it will minimize coordination of activities associated with a refueling outage.
It will also allow additional time for planning the staged modificath,n approach to meet TS action times and address any related issues.
l TVA has determined that performance of the modification during power operation will not initiate reactor trips.
There is a potential for inadvertent diesel generator start signals or 6.9 kv shutdown board load shedding, which would be considered an engineered safety feature actuation.
The consequences of such conditions, should they occur, do not generate a reactor trip or significant safety concerns.
1 The staff has evaluated the licensee's analysis and determined that sufficient justification has been provided to allow delaying implementation of TS Amendment Nos. 182 and 174 for SQN Units 1 and 2, respectively, until desired conditions, plant procedures, modification plans, and modification schedules can Le processed and established in fiscal year 1995.
Therefore, the proposed change is acceptable.
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3.0 STATE CONSULTATION
l In accordance with the Commission's regulations, the Tennessee State official was notified of the proposed issuance of the amendments.
The State official l
had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission previously issued a proposed finding that the amendments involve no significant hazards consideration related to the original amendments, and there has been no public comment on such finding (59 FR 4947).
The Commission repeated the proposed finding that the amendments involve no significant hazards consideration in rela + ion to the request to change the implementation date, and there has been no public comment on such finding (59 FR 47182).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The Co misrion has concluded, based on '
a n,siderations discu ed above, that:
'l) there is reasonable assuri :ct thn the health and saiaty of the public will not be endangered by oper ation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulatio. 3, I
and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
David E. LaBarge Dated: October 17, 1994 l
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