ML20212J326
| ML20212J326 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 10/01/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20212J322 | List: |
| References | |
| NUDOCS 9910050116 | |
| Download: ML20212J326 (4) | |
Text
pn40 p
.4 UNITED STATES g
,j NUCLEAR REGULATORY COMMISSION WASHINGYoN, D.C. 2055M001
,o
- SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.177 TO FACILITY OPERATING LICENSE NO. DPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-27,1 1,0 INTRODUCTION By letter dated July 20,1999, as supplemented by letter dated August 17,1999, the Vermont Yankee Nuclear Power Corporation (the licensee) submitted a request to amend the Vermont Yankee Nuclear Power Station (Vermont Yankee) Technical Specifications (TSs). The proposed amendment would revise and clarify the operability and surveillance requirements of the high pressure core cooling systems TSs.
2.0 BACKGROUND
The proposed changes involve the high pressure coolant injection (HPCI) system, reactor core i
isolation cooling (RCIC) system, and automatic depressurization (AD) system. The HPCI system ensures that the reactor core is adequately cooled in the event of a postulated small break loss-of-coolant accident (LOCA). The RCIC system provides makeup water to the
{
reactor vessel following a reactor vesselisolation when normal sources of feedwater are not available. While not designed or credited as an emergency core cooling system (ECCS), RCIC functions similarly to the HPCI system. Both the HPCI and RCIC systems use a steam-driven turbine-pump to provide water to the reactor vessel. The steam supply for these pumps is the i
reactor.
The AD system serves as a backup to the HPCI system in the event of a small break LOCA.
The AD system can reduce the reactor system pressure to allow the low pressure cooling systems to provide water to cool the core.
Since the HPCI, RCIC, and AD systems are high pressure systems, certain tests on these systems require high pressure steam. The current TSs state that these systems must be operable before exceeding certain pressures; however, all required testing cannot be performed before these pressures are exceeded. The proposed TSs correct this condition.
3.0 EVALUATION 3.1 Clarification of Reactor Steam Pressure The licensee proposed revising TSs 3.5.E.1,3.5.F.1, and 3.5.G.1 by changing " reactor pressure" to " reactor steam pressure" to indicate that these TSs that are associated with HPCI, RCIC, and AD systems apply when reactor steam pressure is above the specified values. The 9910050116 991001 PDR ADOCK 05000271 P
c.
c
. licensee stated that this was necessary to clarify ine applicability since hydrostatic or leakage testing could result in reactor prassure exceeding the specified limits; however, these systems chnnot operate without adequato steam flow and steam pressure. The staff agrees with this clarification since these systems cannot operate, and are not necessary without steam.
Therefore, the proposed change is acceptable.
In addition, the licensee proposed changing the HPCI TS 3.5.E.1 which currently reads "Except as specified in Specification 3.5.E.2, whenever irradiated fuel is in the reactor vessel and reactor pressure is greater than 150 psig and prior to reactor startup from a cold condition:" by deleting the statement "and prior to reactor startup from a cold condition:." The effect of this change i:a to remove the requirements that HPCI be operable and the condensate storage tank (CST) shall contain at least 75,000 gallons of condensate water prior to reactor startup. The licensee stated that MPCI is not needed below 150 psig reactor steam pressure. The CST has a reserve volume of 75,000 gallons for HPCI and RCIC purposes only and these two systems are not needed below 150 psig reactor steam pressure. Therefore, the dicensee stated that it is not necessary to require these items prior to reactor startup from a cold condition. At and below 150 psig reactor steam pressure the low pressure ECCS are adequate to maintain core
. cooling. The staff finds the proposed change in be acceptable because requiring these items when reactor steam pressure is above 150 psig is adequate to ensure adequate core cooling during design basis events.
3.2 HPCI and RCIC Testing Requirements The licensee proposed replacing the HPCI testing requirement of TS 4.5.E.1 with the following:
1.
Testing a.
A simulated automatic actuation test of the HPCI System shall be performed during each refueling outage, b.
Operability testing of the pump and valves shall be in accordance with Specification 4.0.E.
c.
Upon reactor startup, HPCI operability testing shall be pe;1ormed as required by Specification '. 6.E within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding 150 psig reactor steam pressure.
d.
1 he HPCI System shall deliver at least 4250 gpm at normal reactor operating pressure when recirculating to the Condensate Storage Tank.
Similarly, the licensee proposed replacing the RCIC testing requirement of TS 4.5.G.1 with the following:
1.
Testing a.
A simulated automatic actuation test (testing valve opo ability) of the RCIC System shall be performed during each refueling outage.
h
- .. b.
Operability testing of the pump and valves shall be in accordance with Specification 4.6.E.
'Upon reactor startup, RCIC operability testing shall be performed as c.
required by Specification 4.6.E wiutin 24 h >urs after exceeding 150 psig reactor steam pressure.
d.
The RCIC System shall deliver at least 400 gpm at normal reactor operating pressure when recirculating to the Condensate Storage Tank.
Items a, b, and d above are equivalent to the current TS fw testing of HPCI and RCIC. These changes are administrative since only the formaQg has changed from the current TS.
Because these changes do not constitute a change in technical meaning of the TS, proposed changes a, b, and d above for testing HPCI and RCIC are acceptable to the staff.
}
Proposed TSs 4.5.E.1.c and 4.5.G.1.c for testing of HPCI and RCIC do not exist in the current j
TS. At and below 150 psig reactor steam pressure the low pressure ECCSs are adequate to maintain core cooling; HPCI and RCIC are not necessary. Adequate steam pressure and flow are not available to perform the specified sunmillance testing of HPCI and RCIC when reactor steam pressure is less than 150 psig. The staff considers that reactor startup is allowable prior to performing the surveillance tests because the time allowed to satisfactorily perform the oirveillance test is short (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) and the systems should be functional even though the surveillance test has not been completed. The 24-hour limit is consistent with the actions required by TSs to reduca reactor steam pressure below 150 psig if HPCI or RCIC are inoperable and certain other conditions are not met. The Staff considers the proposed changes to be acceptable because the tet.cng cannot be performed below 150 psig, the systems should be functional before the surveillance test is performed, and the time to perfoirr, the surveillance after exceeding 150 psig is short and consistent with the action statements for system
- noperablity.
I 3.3 Additional Allowance in HPCI and RCIC Action Statements The licensee proposed changing HPCI TS 3.5.E.3 to add the following italicized items:
"If the requirements of either Specification 3.5.E or Specification 4.5.E.f.c cannot be met, an orderly shutdown shall be initiated....."
5.cnilar!y, the licensee proposed changing RCIC TS 3.5.G.3 to add the following italicized items:
"If the requirements of either Specification 3.5.G or Specification 4.5.G.f.c cannot be met, an orderly shutdown shall be initiated....."
These char.ges incorp; rete into the TS required actions the allowance of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, after exceeding 150 psig reactor steam pressure, to perform HPCI and RCIC operability testing as discussed in section 3.2 of this evaluation. The staff considers these changes to be acceptable because it is nc+ necessary to perforni the actions specified (re&ctor shutdown and reactor pressure reduction) provided the operability testing of the HPCI and RCIC systems is performed as specified in the TS and discussed in sectior 3.2 of this evaluation.
7 n
3 l
' j 3.4 Specification of 150 psig Reactor Pressure for HPCI, RCIC, and AD systemr, Requirements The licensee proposed changes to TS sections 3.5.E,3.5.F,3.5.G, and 3.6.D to reflect that the appropriate reactor pressure associated with HPCI, RCIC, and AD systems requirements is 150 psig. The current TS was inconsistent and specified pressures of 100 psig,120 psig, and 150 psig. As previously stated, at and below 150 psig reactor steam pressure the low pressure ECCSs are adequate to maintain core cooling. HPCI, RCIC, and AD systems are not necessary to meet the Vermont Yankee licensing basis or satisfy emergency core cooling needs at and below 150 psig reactor steam pressure. Therefore, the proposed changes are acceptable.
3.5 Basis Changes The licensee proposed TS bases changes to reflect the TS changes discussed in this evaluation. The staff has reviewed these changes and has no objection to the proposed TS bases changes.
4.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Vermont State official was notified of the proposed issuance of the amendment. The State official 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 defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in amounts, and no significant change in the types of any effluents that may l
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 (64 FR 47537). 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 irnpact statement or environmental assessrnent 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 an'1 vafety of the public will not be endangered by operation in the p ro,+ menw, Q) such activities will be conducted in compliance with the Commission's regu'ations, and (3) the issuance of the amendment will not be inimical to the common defense yd security or to the health and safety of the public.
Principal Contributor: R. Croteau Date: October 1, 1999