ML20217G725
| ML20217G725 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/30/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217G722 | List: |
| References | |
| NUDOCS 9710140173 | |
| Download: ML20217G725 (4) | |
Text
03Meu
/t UNITED STATES y*
3 NUCLEAR REGULATORY COMMISSION WASHINGTON D.C. 3026-0001 k.,.. +
SAFETY EVALVATION BY THE OFFICE OF NUGLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 208 TO FACillTY OPERATING LICENSE NO. DPR-65 NORTHEAST NUCLEAR ENERGY COMPANY THE CONNECTICUT LIGHT AND POWER COMPANY THE WESIIRN MASSACHUSETTS ELECTRIC COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 2 DOCKET NO. 50-336
1.0 INTRODUCTION
By letter dated A)ril 10, 1997, the Northeast Nuclear Energy Company, et al.
(the licensee) su>mitted a request for changes to the Millstone Nuclear Power Station, Unit No. 2, Technical Specifications (TSs).
The proposed changes would modify the TSs for the enclosure building.
Specifically, the proposed changes would relocate the surveillance requirement for attaining a negative pressure in the enclosure building from TS 3.6.5.1
" Enclosure Building Filtration System," to TS 3.6.5.2, " Enclosure Building Integrity." TS 3.6.5.2 would also be changed to address operability, which includes integrity requirements, and Definition 1.25, " Enclosure Building Integrity," would be deleted.
TS 4.6.5.2, ' Surveillance Requirements," would be modified to require each access opening in the enclosure building to be closed instead of the current requirement to close each door (some access openings have two doors in series) in each access opening.
This TS would also be renumbered as 4.6.5.2.1.
Editorial changes are proposed for clarification and consistency. The TS Bases and index pages would also be updated to reflect the proposed changes including the need to maintain the integrity of the enclosure building and to support previously approved laboratory testing requirements for charcoal filter sample testing.
2,0 BACKGROUND The enclosure building is a limited-leakage, steel-framed structure that completely surrounds the containment.
It is designed and constructed to ensure that any leakage of radioactive materials to the environment would not exceed an acceptable upper limit in the event of a design basis loss-of-coolant accident (LOCA) or movement of loads over the spent fuel pool. A slight negative pressure is maintained by the enclosure building filtration system (EBFS) and the system exhausts the air through charcoal and high-
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-2 efficiency particulate air (HEPA) filters prior to discharging to the atmosphere.
The enclosure building filtration region (EBFR) encompasses an area between the containment and enclosure building, the penetration rooms, and the engineered safety feature room.
The BFS maintains a slightly negative pressure of.25 inch water gauge within 60 seconds of receiving an actuation signal following a LOCA. Thus, air being discharged from the EBFR would be arocessed through the charcoal and HEPA filters located in the EBFS prior to seing released to the atmosphere during a LOCA as previously noted.
- However, the EBFS can also be pow: red by the emergency diesel generators (EDGs) if the normal source of power is lost concurrent with a LOCA.
To account for this situation, the safety analysis for Millstone Unit 2 conservatively assumes that the release of radioactivity from the primary containment will continue for 110 seconds until the EDGs are started, the EBFS is powered and the required negative pressure is established, it is necessary to maintain the integrity of the enclosure building, above and beyond the normal everyday personnel passage through the doorways, to maintain the required negative pressure.
3.0 EVALUATION In relation to the first portion of the request, the licensee has proposed to relocate the surveillance requirement for attaining a negative pressure in the enclosure building from TS 3.6.5.1 " Enclosure Building Filtration System " to TS 3.6.5.2, " Enclosure Building Integrity." The word " Integrity" would be removed from the title of TS 3.6.5.2 and replaced in the TS limiting condition for operation by addressing operability which supports the deletion of Definition 1.25. " Enclosure Building Integrity," and the addition of Surveillance Requirement 4.6.5.2.2.
The licensee also proposes changes to the Bases section to support the requested change.
TS 3.6.5.2 allows 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore the integrity of the enclosure building if it has been breached. However, the licensee notes that the current surveillance requirement in TS 3.6.5.1 to achieve a negative pressure of-
.25 inch water gauge in 60 seconds would likely not be possible. Although the EBFS would still be effective in reducing the levels of radionuclides that could be released to the atmosphere in the advent of a LOCA, the required negative pressure could not be met in accordance with Surveillance Requirement, 4.6.5.1.d 3, currently located in the EBFS TS 3.6.5.1.
As a result, TS ?.0.3 requiring an immediate shutdown, would have to be entered since TS 3.6.5.1 does not address the enclosure building integrity and both trains of the EBFS would be assumed inoperable.
This cascading of TSs has been recognized and corrections have been made in the improved Standard Technical Specifications for Combustion Engineering Plants, NUREG-1432, Sections 3.6.11 and 3.6.13.
The proposed changes to TSs 3.6.5.1 and 3.6.5.2, the relocation of Surveillance Requirement 4.6.5.1.d.3 to TS 3.6.5.2 and renumbered as 4.6.5.2.2, changes to Bases "ections 3/4.6.5.1 and 3/4.6,5.2, the use of operability instead of int -
.y in TS 3,6.5.2, and the deletion of Definition 1.25 will reso' the conflict that currently exists between
-3 TSs 3.6.5.1 and 3.6.5.2.
Specifically, the requirement to establish and maintain a negative pressure in the enclosure building boundary included in TS 3.6.5.1 belongs in TS 3.6.5.2.
In the event enclosure building operability is not maintained in Modes 1 through 4, the action statement for the limiting condition for operation TS 3.6.5.2, requires that enclosure building operability must be restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Twenty-four hours is a reasonable completion time considering the limited leakage design of containment and the low probability of a design-basis accident occurring during this time period.
Therefore, the NRC staff has determined that the proposed changes are acceptable.
l The second portion of the request would modify TS 4.6.5.2, "Surveillence Requirements," to require each access opening in the enclosure building to be closed instead of the current requirement to close each door (some access openings have two doors in series) in each access opening, " integrity" would be revised to address operability, and would also be renumbered as Surveillance Requirement 4.6.5.2.1.
All access doors are considered operable when they are capable of automatically closing and latching.
The current design of the enclosure building incorporates double doors in some of the enclosure building access openings.
The licensee notes that there is no credit given for the redundant doors in the radiological dose calculations performed for the design-basis accidents. All single doors are currently required to be shut and latched except for normal 3assage.
The current TS requirement in the double door design requires bot 1 doors be closed and latched even though credit is not given for the redundant design.
1he NRC issued Amendment No. 45 to Facility Operating License No. DPR-65 for Millstone Nuclear Power Station, Unit 2 on December 8,1978.
The NRC staff indicated in its supporting Safety Evaluation that several of the access openings in the enclosure building only had a single door and approved celeting the requirement to have at least one door closed in an opening during normal passage.
The original TS requirement incorrectly assumed double doors in all of the access openings, thus, a single door closure is acceptable to assure the integrity of the enclosure building considering normal passage.
Therefore, the preposed change that requires only one door in the redundant door de ign be shut and latched, except for normal passage, is acceptable.
The thi gortion of the request involves proposed changes to provide consistu.y within the existing TSs and to support the proposed changes discussed above. The inuex pages will be updated, consistency in the use of capital letters and the interchangeable use of " system" and " train" will be changsd to use " train" where appropriate.
TS 3.9.5, " Storage Pool Area Ventilation System - Fuel Storage," currently requires that at least one
" system" However, the required a(uill be changed to " train") of the EBFS be operable.
ction statement refers to the spent fuel pool ventilation system instead of the EBFS.
This inconsistency would be corrected by changing the action statement to refer to the EBFS.
TS Bases Sections 3/4.6.5.1, 3/4.6.5.2, and 3/4.9.15 would be modified to reflect the proposed changes.
In addition, TS Bases Sections 3/4.6.5.1 and 3/4.9.15 would se updated to clarify the laboratory testing requirements that have been previously approved by the NRC staff. The testing requirements were approved in Amendment No. 175 to
-4 I
Facility Operating License No. DPR-65 for the Millstone Nuclear Power Station, i
Unit 2, dated May 23, 1994.
The proposed changes provide' clarification and needed consistency with respect to requirements, the containment enclosure building and to clarify laboratory testing requirements previously apprwed by amendment; therefore, these changes are acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations the Connecticut State official wu notified of the proposed issuance o,f the amendment.
The State official had no comments.
l
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements.
The amendment also relates to changes in record keeping, re wrting, or administrative procedures or-requirements.
The NRC staff las determined that the amendment involves 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 finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 24987 dated May 7, 1997).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR Sl.22(b no environmental impact statement or environmental assessment need be prep)ared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safet public will not be endangered by operation in the proposed manner,y of the (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
D. Mcdonald Date:
September 30, 1997
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