ML20217Q734
| ML20217Q734 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/27/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217Q730 | List: |
| References | |
| NUDOCS 9709030338 | |
| Download: ML20217Q734 (4) | |
Text
'
p0 ~%
p t
UNITED STATES g
P; NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 30W6 4001
- .+
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.203 TO FAClllTY OPERATING LICENSE NO. DPR 50 METROPOLITAN EDIS0N COMPANY JERSEY CENTRAL POWER & LIGHT COMPANY P[NNSYLVANIAELECTRICCOMPANY GPU NUCLEAR CORPORATION THREE MILE ISLAND NUCLEAR STATION. UNIT NO. 1 DOCKET NO. 50-282
1.0 INTRODUCTION
By letter dated April 21, 1997, assupplementedbyletterdatedJuly 17, 1997 GPU, the licensee for Three Mile Island. Unit 1 (TM1-1), submitted Technical S>ecification Change Request (TSCR) No. 263." requesting three changes to t1eir Technical Specifications (TS).
Specifically, the proposed TS changes include TS 3.3.1.2 to decrease the Core Flood Tank borated water volume to 940 3
3 ft from 1040 ft : TS 4.5.2.1.b to decrease the surveillance acceptance criteria of the high pressure injection (HPI) flow rate from 500 gallons per minute (gpm) to 431 gam: and TS 3.3.1.1.f to assume credit only for remote manual operation of tie decay heat valves instead of local or remote manual operation.
The first two changes are being requested to maintain the acceptance criteria with the impending power uprate to 2620 megawatts thermal (MWt) at mid cycle, during Cycle 12 (the power uprate will be requested separately).
Several editorial changes to the TS have also been proposed.
The July 17. 1997, submittal provided clarifying information that did not affect the initial no significant hazards determination.
2.0 EVALUATION 2.1 Valves DH-V 6A/B Operability During a recent inspection at TMI (Inspection Report 50 289/96 201), the NRC staff noted that the use of the current TS 3.3.1.1.f could result in operation of the plant outside of the design basis. While this TS has existed since the original operating license was granted, it was determincd that design basis operation would be exceeded with respect to the dose consequences and the time allowance for op/B) were operated by local controls,erator actions if the two reactor b valves (DH-V 6A c
h
2 As stated. 'the TS cllows for either local manual or remote manual operation of DH V 6A/B valves.
The operator response time for opening these valves, as assumed by the calculations for borated water storage tank (BWST) drawdown and swapover to the reactor building sump, was based on opening the valves by remote manual operation. Also, the manual operation of these valves during plant operation may not be possible in the decay heat removal system pump room because of the high radiation conditions.
Therefore, the licensee pro wording"eithermanually0;posestocorrectTS3.3.1.1.fbydeletingthethus allowing only rem these valves. As the TS is currently stated. the licensee is able to remain in compliance with only local-manual operation capability and diverts to TS 3.0.1 when both local and remote manual operation are unavailable. With the proposed TS change, the licensee is diverted to TS 3.0.1 when the remote-manual operation is unavailable.
The staff finds this TS change is more restrictive and it is, therefore, acceptable.
2.2 Core Flood Tank The purpose of the core flood tank (CFT) is to provide borated water to the reactor vessel during the blowdown phase of a loss of-coolant accident (LOCA).
to provide a portion of the inventory for the refill phase that follows, and to 3rovide Reactor Coolant System (RCS) makeup for a small break LOCA (SB.0CA)
The CFT is partially full of borated water, pressurized by nitrogen and connected by a single injection line to the reactor vessel downcomer.
This. passive system is activated when the RCS pressure drops below the CFT pressure and the borated water is injected in to the vessel downcomer. - The-CFT provides the initial injection of borated water following a LOCA before the active systems, high pressure and low pressure injection, are activated.
The current CFT inventory and pressure of 1040 fta and 600 psig, respectively, are based on the analyses to evaluate the effects of pre-accident CFT level and pressure on the LOCA linear heat rate (LHR) limits and were performed _by-Framatome (FTI) for the B&W Owners Group Analysis Commictee.
The-sensitivity studies performed by the licensee for the impending power uprate indicated that the )ower uprate could increase the peak cladding temperature. (PCT) beyond tie limits of 10 CFR 50.46, following a LOCA.
The CFT injecticn occurs at a critical time during the reflood phase of the transient, when the core is experiencing an adiabatic heatup with very little liquid inventory remaining in the reactor vessel. The increase in power will cause an increase in LHR and therefore require more inventory or higher injection rate to maintain the limits of 10 CFR 50.46.
Since the CFT pressure of 600 psig is a)proaching the pressure limit of the
-CFT. the licensee decided to decrease tie. inventory to 940 30 ft. wnile 8
maintaining the same nitrogen pressure. As proposed, this change would allow
.the CFT inventory to fill the reactor vessel at a higher flow rate because of the increased pressure ratio to inventory.
-Thelicensee'sanalys1stosugportthisTSchangewasincludedinthepecent LOCA analyses performed at 27 2 MWt with pre accident values of 905 ft
=
igg
____..:._..___a.
. inventpryand580psiapressure.
These values bound the TS values in that:
985 ft is the greatest volume of inventory that can be delivered to the reactor vessel. at a rate that will prevent exceeding the limits of 10 CFR 50.46: and the pressure of 580 psia is the lowest pressure that will activate the CFT in a timely manner to prevent exceeding the acceptance criteria.
Currently nitrogen is released to the RCS once the liquid inventory is depleted. With the proposed TS. there will be an increased amount of nitrogen released to the RCS because of the reduced volume and increased 3ressure.
The licensee has evaluated this change and determined that during a
_BLOCA. the core-flow is so turbulent that adequate core heat transfer will exist even with entrained nitrogen.
The nitrogen may collect in the once-through steam generators (OTSGs) or reactor coolant loops but the OTSGs are not used for heat-removal.
The licensee stated that this change results in the reduction of the post LOCA-reactor building sump inventory reduction of 4" or 1500 gallons and a reduction of the total sum) recirculation volume of 0.375%.
The licensee also concluded that, based on t1e small change in these two volumes, the net positive suction head of the emergency core cooling system pump when taking suction from the reactor building sum). the boron concentration, the dose consequences and changes in the post 0CA reactor building pressure and temperature are all within the acceptance criteria.
The resultant LBLOCA PCT of 2041'F is also with % the acceptance criteria of 2200*F.
2.3 High Pressure Injection Flow Rate Change Credit for the HPI pumps are included in the SBLOCA analyses only. The pumps are actuated either automatically by low RCS pressure or manually on loss of subcooling margin.
The licensee is requesting to reduce the HPI flow from 500 g>m to 431 gpm. The reduction could result in reduced core cooling and extend t1e time it takes to refill the RCS following initiation.
The licensee's new LOCA analyses include the HPl flow rate of 431 gpm at 2772 MWt. With the resultant SBLOCA PCT of 1444.4*F. remained below the acceptance criteria of 2200'F and the maximum amount of core wide oxidation and calculated local cladding were within the acceptance criteria.
3.0
SUMMARY
The staff has reviewed the licensee's request to change the operation of decay heat valves to remote manual operation only in TS 3.3.1.1.f.
The licensee indicated that this change is consistent with the calculations for BWST drawdown and swapover to the reactor building sump and since this change results in a more restrictive TS. the staff finds this TS change acceptable.
The Raff also reviewed the request to reduce the inventory in the CFT from 1040 ft to 940 fta in TS 3.3.1.2 and reduce the high pressure injection flow rate from 500 gpm to 431 gpm in TS 4.5.2.1.
Since both analyses were based on a> proved methodologies and all acceptance criteria remained within the limits.
tie staff finds these TS changes acce) table.
The 3roposed editorial changes revise TS 4.5.2.1.a and b so that "M. J." reads "ma ceup": in TS 4.5.2.1.c.(1) l
y e.
q 4-f the word "the" was changed to "than"; and in TS 4.5.2.2.b. the words " equal or greater than" were changed to " equal to or greater than." These editorial changes clarify the TS and are acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations the Pennsylvania State
- official was notified of the proposed issuance of the amendment.
The State official had no coments.
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-a surveillance requirement.
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 si occupational radiation exposure.gnificant increase in individual or cumulative The Comission 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 27795). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9),
l'ursuant 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 safet public will not be endangered by operation in the proposed manner,y of the e
(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:
S. Brewer Date:.-August 27. 1997
. + _ _.
-______._m-_--