ML20217C849
| ML20217C849 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 10/05/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217C845 | List: |
| References | |
| NUDOCS 9910140074 | |
| Download: ML20217C849 (4) | |
Text
q k
gpW909 3
UNITED STATES f1.
f
,,j NUCLEAR REGULATORY COMMISSION l
- f WASHINGTON. D.C. 20555-0001 9.....,g i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO' AMENDMENT NO. 64 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION. UNIT NO.1 DOCKET NO. 50-443
1.0 INTRODUCTION
By letter dated March 27,1998, as supplemented June 17,1998, the North Atlantic Energy Service Corporation (the licensee) submitted a request for changes to the Seabrook Station Technical Specifications (TSs). The requested changes would revise TS 3.7.6.1, Control Room Emergency Makeup Air and Filtration Subsystem (CREMAFS), and TS 3.7.6.2, Control Room Air Conditioning Subsystem (CRACS) to delete the restriction to suspend all operations involving positive reactivity changes during the plant conditions specified. The June 17,1998.
letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
2.0 BACKGROUND
Per section 9.4.1.2 of Seabrook's Updated Final Safety Analysis Report (UFSAR), CREMAFS is a subsystem of the control room heating, ventilation, and air conditioning system. Section 6.5.1.1.c of the UFSAR states that CREMAFS is designed to supply makeup air to the control room following an accident or a release of radiological contaminants or smoke, to maintain a positive pressure within the control room complex, and to remove and retain airborno particulates and radioactive iodines from all makeup air and a portion of the recirculated air.
i Per section 9.4.1.3 of the UFSAR, the location of the air ' intakes, in conjunction with the system's particulate and iodine filtration efficiency, satisfies the control room dose criteria j
specified in General Design Criteria (GDC) 19 of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A, General Design Criteria for Nuclear Power Plants. Section 9.4.1.3 of the UFSAR also states that the filtration systems and associated fans and dampers
. are designed as Engineered Safety Features in accordance with Regulatory Guide 1.52, as clarified in Subsection 6.5.1 of the UFSAR.
Per section 9.4.1.2 of the UFSAR, CRACS is also a subsystem of the cor trr' e ccmcl..
heating, ventilation, and air conditioning system. Section 9.4.1.1 of the UFSAR states that the 9910140074 991005 pDR ADOCK 05000443 PDR
t ;-
j J
t
)
. cooling system is designed to maintain the control room temperature at or below design maximum temperatures when the outside air temperature is 88 *F or lower. Seabrook's CRACS provides cooling of the control room complex in accordance with GDC 4 and 19 of 10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants.
TS 3.7.6.1 requires that Seabrook's CREMAFS is operable during all modes of operation. If the plant is operating in Modes 1 through 4, and both trains of CREMAFS become inoperable, TS 3.0.3 requires a shutdown which necessitates reducing the average Reactor Coolant System (RCS) temperature to s 200 *F. However, upon reaching 200 *F, ACTION statement b. of TS 3.7.6.1 becomes applicable and includes the requirement to suspend all operations i
involving positive reactivity changes. Consequently, TS 3.7.6.1 prevents reducing the RCS l
temperature to any value less than exactly 200 "F since a cooldown below 200 F is considered a positive reactivity change. Therefore, TS 3.7.6.1 imposes impractical operational restrictions under these circumstances.
Similarly, TS 3.7.6.2 requires that CRACS is operable during all modes of operation and imposes the same impractical operational restrictions if both trains of CRACS become inoperable in Modes 1 through 4 and the plant is required to enter Mode 5.
j This restriction caused an operational problem at Seabrook that was reported to the NRC in Licensee Event Report (LER) 97-18 " Control Room Emergency Makeup Air and Filtration Subsystem Inoperability." On December 16,1997, the plant was in Mode 4 and commenced a plant shutdown per TS 3.0.3 as a result of both trains of the CREMAFS being inoperable per TS 3.7.6.1. TS 3.0.3, which is applicable only during Modes 1 through 4, was exited upon reaching Mode 5, where TS 3.7.6.1 became applicable and required the suspension of all operations involving positive reactivity.
According to the LER, during the cooldown into Mode 5, control room operators reduced the RCS temperature from 200 *F to approximately 180-190 F to ensure the that plant was maintained in a stable condition. To offset the positive reactivity change as a result of the cooldown, the operators borated the RCS which resulted in a net negative reactivity. However, regardless of the boration, the cooldown action was still a positive reactivity change and was determined to be reportable pursuant to 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the plant's TSs.
Therefore, the purpose of this amendment request is to delete the restriction to suspend all operations involving positive reactivity changes in TS 3.7.6.1 and 3.7.6.2 which cannot practically be avoided during specific plant conditions.
3.0 EVALUATION TS 3.7.6.1 requires that tv6 :..'q cndr ! CiCMAFS trains be operable during all modes of operation. For operational modes 5 and 6, the TS states:
"With one Control Room Emergency Makeup Air and Filtration Subsystem inoperable, restore the inoperable system to OPERABLE status within 7 days or initiate and 4
j N
(
l4 f
L !.
l' maintain operation of the remaining OPERABLE Control Room Emergency Makeup Air and Filtration Subsystem in the filtration / recirculation mode."
or "With both Control Room Emergency Makeup Air and Filtration Subsystem inoperable, l
or with the OPERABLE Control Room Emergency Makeup Air and Filtration Subsystem, required to be in the filtration / recirculation mode by ACTION a., not capable of being -
' powered by an OPERABLE emergency power source, suspend all operations l
Involvina CORE ALTERATIONS or positive reactivity chances." (Emphasis added.)
j.
TS 3.7.6.2 requires that two independent CRACS trains be operable during all modes of
~
l operation. - For operational modes 5 and 6, the TS states:
"With one Control Room Air Conditioning Subsystem inoperable, restore the inoperable i
system to OPERABLE status within 30 days or initiate and maintain operation of the remaining OPERABLE Control Room Air Conditioning Subsystem or immediately l-suspend all operations involvina CORE ALTERATIONS or positive reactivity chances." (Emphasis added.)
or "With both Control Room Air Conditioning Subsystems inoperable, or with the OPERABLE Control Room Air Conditioning Subsystem unable to maintain temperature l
below the limiting equipment qualification temperature in the control room area, suspend all operations involvina CORE ALTERATIONS or positive reactivity chances." (Emphasis added.)
l.
. The restriction to suspend all operations involving positive reactivity changes in Modes 5 and 6
- inappropriately prevents cooling the RCS temperature below 200 *F when Mode 5 is entered as a result of both trains of CREMAFS, or both trains of CRACS, being inoperable. The restriction j
also inappropriately prevents minor variations of the RCS temperature while in Modes 5 and 6.
In addition, the restriction is redundant to TS 3.1.1.2, " Reactivity Control Systems Shutdown
. Margin -T,y Less Than Or Eque.! rc 200 *F"in Mode 5 and TS 3.9.1 " Refueling Operations
- Boron Concentration"in Mode 6. TSs 3.1.1.2 and 3.9.1 provide the necessary protection for postulated reactivity addition accident conditions and maintaining shutdown margin within acceptable limits which allows for deliberate evolutions (such as smail changes in temperature j
and bo' on concentration), without adversely affecting the net core reactivity.
r Furthermore, the proposed change to delete the restriction to suspend all operations involving positive reactivity changes in Modes 5 and 6 with both trains of CREMAFS inoperable or both trains of CRACS inoperable is consistent with similar actions in NUREG-1431 " Standard Technical Specifications Westinghouse Plants."
' Therefore, based on the information contained in the application, Seabrook's TSs, UFSAR,
. NUREG-1431, and LER 97-018-00, the staff finds that the proposed change to delete the 2
l m
q to
!. restriction to suspend all positive reactivity changes from TS 3.7.6.1 and TS 3.7.6.2 is J acceptable.
4.0 STATE CONSULTATION
. In accordance with the Commission's regulations, the New Hampshire and Massachusetts State officials were notified of the proposed issuance of the amendment. The State officials had no comments.
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 definod in 10 CFR Part 20. The NRC staff has 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 (63 FR 19973). Accordingly, the amendment meets 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 amendment.
6.0 CONCLUSION
The Commission 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, (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: John Harrison Date:
0ctober 5, 1999 a