ML20204H845
| ML20204H845 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/14/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20204H803 | List: |
| References | |
| NUDOCS 8810240485 | |
| Download: ML20204H845 (3) | |
Text
e e g3 UNITED STATES NUCLEAR REGULATORY COMMISSION a
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SAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS SUPPORTING AMEN 0 MENT f:0. 89 TO FACILITY OPERATING LICENSE NO. DPR-77 AND AMENDMENT NO. 78 TO FACil.ITY OPERATING LICENSE NO. DPR-79 TENNESSEE VALLEY AUTHODITY SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET N05. 50-327 AND 50-328
1.0 INTRODUCTION
(TVA) requested the Tennessee Valley Authority (TS).
By the letter dated May 29, 1987, a change to the Sequoyah Units 1 and 2 Technical Specifications The change is to TS 3.6.5.2 involving the Action Statements for the limiting condition for operation (LCO) of the ice bed temperature monitoring system.
TVA proposes to delete the Action Statement "b" for LCO 3.6.5.2.
This Statement allows continued power operation for up to 30 days when the ice bed monitoring system is inoperable, and personnel are unable to determine the ice bed temperature at the local panel, provided that the ice condenser cooling system is operable, the ice condenser doors are closed and the last recorded mean ice bed temperature was less then or equal to 20*F.
With the deletion of Action Statement "b", Action Statement "c" would apply.
This Statement allows power operation to continue for only up to six days provided the ice condenser doors are closed and the last recorded mean ice bed temperature was less than or equal to 15'F.
2.0 EVALUATION The ice condenser system is described in Sections 6.2.3 and 6.5 of the Sequoyah Final Safety Analysis Report (FSAR).
The function of tie ice condenser system is to provide pressure suppression capability to the primary containment in the event of a Design The system consists of a completely enclosed annular c, Basis Accident (DBA).ompartment formed between the crane which contains a large inventory of borated ice maintained at 15 to 20'F throughout o 300* arc of the containment. The compartrent walls are lined with thermal insulation and cooling ducts which are supplied with refrigerated air from 30 pairs of air handling units (AHus) located in the corpartment above the ice inventory.
The ice condenser fl1or is also insulated and cooled. A circulating system of 50 percent ethylene q:ycol solution carries heat from the AHUs and embedded floor cooling coils to a number of glycol chillers located in the auxiliary building.
The TS 3.6.5.1 requires that a mMrun ice bec tenperature o' less than or equal to 27'F be raintained for the ice bed to be considered operable.
The ice 8810240485 881014 ADOCK0500py7 DR
2-bed temperature monitoring system provides assurance of meeting this temperature limit by verification that the monitoring system is operable at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
In the event the monitoring system is inoperable and the ice bed temperature can not be determined, the Action Statements for LC0 3.6.5.2 must be followed and they provide assurance that the ice bed heat removal capacity is retained for the specified time limits that plant operation is allowed to continue. Action Statement "b" allows continued power operation for 30 days provided the ice condenser cooling system is operable (with 21 AHUs, two glycol pumps and three refrigerant units operable), the ice condenser doors are closed and the last mean ice bed temperature is not above 20*F.
Action Statement "c" allows continued operation for six days provided the ice condenser doors are closed and the last recorded mean ice bed temperature is not above 15'F.
TVA stated in its submittal that the pre-operational test data for the AHUs showed deficiencies in meeting the performance reouirements.
Specifically, TVA explained that the design calculations do not support the requirements of Action Statement "b" for the number of operating AHUs required to ensure that a mean ice bed temperature of less than or equal to 27'F is maintained for 30 days.
However, TVA states that the ice condenser cooling system adequately performs to meet Action Statement "c" as revised.
The phrase proposed to be deleted from Action Statement "c" states that the ice condenser cooling system does not satisfy the mininum component operability requirements listed in Actinn Statement "b".
These are the requirements on the AHUs that TVA states do not support Action Statement "b" and an acceptable mean ice bed temperature below 27'F for 30 days.
Therefore, TVA is proposing to delete both the phrase and Action Statement "b".
Keeping the phrase in Action Statement "c" and deleting Action Statement "b" would be inconsistent and Action Statement "c" is based on the ice condenser cooling system being inoperable.
Based on the above, the staff has determined that deleting Action Statement "b" and relying on Action Statement "c" for the LCO of the ice bed temperature monitoring system is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The 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 has previously issued a proposed findino that these amendments involve.30 significant hazards consideration and there has been no public criteria for catecorical exclusion set forth in 10 CFR 51.??(c)(9)gibility cc.rment on such finding. Accordingly, the amendments meet the eli Pursuant to 10 CFR 51.?2(b), no envirnnmental impact Statement nor environmental i ssuance of these assessment need be prepared in connection with the arendments.
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4.0 CONCLUSION
The Commission made a proposed determination that the amendment involves no significant hazards consideration which was published in the Federal Register (52 FR 39308) on October 21, 1987 and consulted with the State of Tennessee on October 12, 1988.
No public comments were received and the State of Tennessee did not have any comments.
The staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comraission's regulations, and the issuance of the amendments will not be inimical to the common defense and security nor to the health and safety of the public.
Principal Contributors:
P. Hearn, J. Donohew nated:
October 14, 1988 t
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