ML20045C615
| ML20045C615 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/16/1993 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20045C607 | List: |
| References | |
| NUDOCS 9306240073 | |
| Download: ML20045C615 (9) | |
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.' ENCLOSURE 1 i
PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND.2 DOCKET NOS.'50-327 AND 50-328 (TVA-SQN-TS-93-05)
LIST OF AFFECTED PAGES i
Unit._1 3/4 6-30 Unit 2 3/4 6-31 9306240073 930616 7-[-
- DR. ADDCK.'OSOO
r CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4.
Verifying that the torque required to keep each door from closing R135l is greater than 78 inch pounds when the door is 40 degrees open.
This torque is defined as the " door closing torque" and is equal to the nominal door torque minus a frictional torque component.
R135 5.
Calculation of the frictional torque of each door tested in accordance with 3 and 4, abo've.
The calculated frictional torque shall be less than or equal to 40 inch pounds.
4.6.5.3.2 Intermediate Deck Doors - Each ice condenser intermediate deck door shall be:
Verified closed and free of frcst accumulation by a visual inspection a.
at least once per 7 days, and b.
Demonstrated OPERABLE at least once per 18 months by visually verifying R135 no structural deterioration, by verifying free movement of the vent assemblies, and by ascertaining free movement when lifted with the applicable force shown below:
Door Lifting Force 37.+
0-1, 0-5 Less than or equal to)([lbs.y,"7 0-2, 0-6 Less than or equal to) TEs~
0-3, 0-7 Less than or equal to.2 M J^ #
0-4, 0-8 Less than or equal to J,8 W 3/ 0 4.6.5.3.3 Top Deck Doors - Each ice condenser top deck door shall be determined closed and OPERABLE at least once per 92 days by visually verifying:
That the doors are in place, and a.
b.
That no condensation, frost, or ice has formed on the doors or blankets which would rest:ict their lifting and opening if required.
SEQUOYAH - UNIT 1 3/4 6-30 Amendment No. 25, 131 March 2, 1990 t_.
1 CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4.
Verifying that the toraue required to keep each door from closing Rll8 l is greater than 78 inch pounds when the door is 40 degrees open.
This torque is defined as the " door closing torque" and is equal to the nominal door torque minus a frictional torque component.
R118 5.
Calculation of the frictional torque of each door tested in accordance with 3 and 4, above.
The calculated frictional torque shall be less than or equal to 40 inch pounds.
4.6.5.3.2 Intermediate Deck Doors - Each ice condenser intermediate deck door shall be:
Verified closed and free of frost accumulation by a visual inspection a.
at least once per 7 days, and Ril8 b.
Demonstrated OPERABLE at least once per 18 months by visually verifying no structural deterioration, by verifying free movement of the vent assemblies, and by ascertaining free movement when lifted with the' applicable force shown below:
Door Lifting Force 7-1.
0-1, 0-5
< 7f 1bs.
- 33. !
2.
0-2. 0-6
$)(lbs.31. 8 3.
0-3, 0-7 5, # 1bs.
- 31. 0 4.
0-4, 0-8 5,28'1bs.
4.6.5.3.3 Top Deck Doors - Each ice condenser top deck door shall'be determined closed and OPERABLE at least once per 92 days by visually verifying:
a.
That the doors are in place, and b.
That no condensation, frost, or ice has formed on the doors or blankets which would restrict their lifting and opening if required, i
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SEQUOYAH - UNIT 2 3/4 6-31 Amendment No. 13, 118 March 2, 1990
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ENCLOSURE 2-PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH-NUCLEAR-PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-93-05)
DESCRIPTION AND JUSTIFICATION FOR ICE CONDENSER INTERMEDIATE DECK DOOR LIFTING FORCE REQUIREMENT REVISION l
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Rescriplinn_of_ Change TVA proposes to modify the Sequoyah Nuclear Plant (SQN) Units 1 and 2 technical specifications (TSs) to include the ice condenser intermediate deck door lifting forces assumed in the current Westinghouse Electric Corporation subcompartment analysis. This change applies to TS Surveillance Requirement (SR) 4.6.5.3.2.b for ice condenser intermediate deck door operability. The result of this change is an increase in the maximum TS lifting force requirement as follows:
Door __
Ergient Lifting Force Proposed Lifting F ICg Q
0-1, 0-5 1 33 lbs.
1 37.4 lbs.
0-2, 0-6 1 30 lbs.
I 33.8 lbs.
0-3, 0-7 1 28 lbs.
I 31.8 lbs.
0-4, 0-8 1 28 lbs.
1 31.0 lbs.
t Renaan for Change SQN presently has requirements for ice condenser intermediate deck door lifting forces that are more conservative than those for other ice condenser nuclear plants and the current Westinghouse analysis assumptions. Westinghouse researched the source of these overly conservative lifting force values and could not determine their origin.
The original lifting forces specified by the Westinghouse Engineering Operating Procedure (EOP), TVA-EOP-6, " Inspection of Intermediate. Deck Doors," were developed from factory testing of production doors and are not as conservative as the requirements contained in the SQN TSs.. SQN has experienced some difficulties in meeting the present TS requirements for intermediate deck door lifting force, necessitating additional maintenance and retesting. The proposed change.would provide additional' operational margin and minimize the potential for introducing unwarranted operability concerns.
Jugilficallon for Change The ice condenser intermediate deck doors provide a barrier between the ice beds and the upper plenum of the ice condenser. This feature minimizes the sublimatior of ice resulting from warm-air intrusion during normal operation and provides an upper-plenum entry and maintenance platform. During accident conditions that result in pressurization of lower containment, these doors, along with the inlet and top deck doors, provide a flow path to upper containment through the ice beds to provide containment pressure control. The intermediate doors also provide a check valve function to prevent reverse flow of air from the upper compartment to the lower compartment.
SRs are included in TSs to ensure the intermediate deck doors are normally closed and capable of prompt opening in the event of an accident requiring air flow through the ice beds for pressure control.
Intermediate deck door operability is required by TSs for Modes 1 through 4.
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Westinghouse has evaluated the subcompartment analysis for their ice-condenser nuclear plant design. For SQN, this analysis is reflected in TVA-COP-6 and Westinghouse Letter TVA-92-195, dated October 23, 1992.
These documents verify that the increased lifting forces requested in this TS change are consistent with the E0P values and are consistent'with the SQN design basis subcompartment analysis assumptions. This change has no impact on the SQN design basis and will remove unnecessary conservatism that could result in unwarranted declaration of door inoperability.
EnYhnDplental Impact Evaluation The proposed change request does not involve an unreviewed environmental question because operation of SQN Units 1 and 2 in accordance with this change would not:
1.
Result in a significant increase in any adverse environmental impact previously evaluated in the Final Environmental Statement (FES) as modified by the staff's testimony to the Atomic Safety and Licensing Board, supplements to the FES, environmental impact appraisals, or decisions of the Atomic Safety and Licensing Board.
2.
Result in a significant change in effluents or power levels.
3.
Result in matters not previously reviewed in the licensing basis for SQN that may have a significant environmental impact.
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PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PIANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-93-05)
DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION I
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e Significant Hazards Evaluation y
TVA has evaluated the proposed technical specification (TS) change and has determined that it does not represent a significant hazards consideration based on criteria established in 10 CFR 50.92(c).
Operation of Sequoyah Nuclear Plant (SQN) in accordance with the proposed amendment will not:
1.
Involve a significant increase in the probability or consequences of an accident previously evaluated.
This change replaces the overly conservative ice condenser intermediate deck door lifting force surveillance requirement (SR) values presently in the SQN TS with the values assumed in the current Westinghouse Electric Corporation subcompartment analysis for SQN.
There is no change to the functions of the intermediate deck doors by the proposed change. This revision will not change any accident-analysis assumptions or results for SQN's design.
The intermediate deck doors provide a barrier for maintaining ice bed temperature and ice mass and provide a flow path through the beds for design basis loss of coolant accidents. These doors are not considered to be the source of any accident. Therefore, this change will not increase the probability of an accident.
Since this change in lifting force is consistent with current SQN accident analysis assumptions, containment response for design basis events is not changed. Therefore, no change in the mitigation of accidents will result from the proposed revision and the consequences of an accident will remain unaffected in comparison with~ current SQN.
accident analyses.
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Create the possibility of a new or different kind of accident from any previously analyzed.
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The intermediate deck doors are passive devices that are not considered to be the source of an accident. Changing the lifting
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force requirements for these doors to be consistent with the current Westinghouse subcompartment analysis will not affect their design functions or their potential to create an accident. Therefore, the-possibility of a new or different kind of accident is not created.
3.
Involve a significant reduction in a margin of safety.
The proposed change is consistent with the current SQN accident analysis assumptions and only removes unnecessary conservatisms associated with intermediate deck door lifting force SRs in the TS.
The effect of this revision will result in no change to the containment response associated with a design basis accident.
l Therefore, the margin of safety assumed in the accident analysis is maintained without change.
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ENCLOSURE 4' PROPOSED TECHNICAL SPECIFICATION' CHANGE SEQUOYAH NUCLEAR PLANT' UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328-(TVA-SQN-TS-93-05)'
WESTINGHOUSE ELECTRIC COP.P0 RATION OPERATING PROCEDURE TVA-EOP-6 f
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