ML20043B441
| ML20043B441 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/18/1990 |
| From: | Mroczka E NORTHEAST NUCLEAR ENERGY CO. |
| To: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20043B439 | List: |
| References | |
| B3532, NUDOCS 9005300038 | |
| Download: ML20043B441 (6) | |
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May 18, 1994 Docket No. ':-245 J llill.
Re:- Technic 11= Specification 3.5.C.1 Mr. T.:T. Martin h
Region I Administrator
'l U.S. Nuclear. Regulatory Comission
~ 475 Allendale Road.
King of Prussia, PA 19406-Dear Mr. Martin i
MillstoneNuclearPowerStation,.Unith.1 Temporary Waiver of Compliance frosh Feedwater Coolant Injection System 1 Limitina condition for onaration 0 k
Northeast ~ Nuclear' Energy Company (NNECO) Technical Spec 1 ll cation 3.5.C,3.
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hereby requests i temporary waiver of compliance from M;11 stone Unit No. 1 A
temporary waiver of compliance is necessary to permit rea i tor operation for up to an additional three days with the Feedwater Coolant In FWCI) system ection (hly evaluate
. inoperable. The waiver would extend-the available time i s thoroug and safely implement plant modifications to the Gas Turbi1e Generator and FWCI' systems..
.NNECO-is diligently working to compleli the-design and implementation.of the modifications prior to the expira ion of the existing seven day Limiting Condition for Operation (LCO) - for, an inoperable FWCI system.
Current Technical Specification requirements will necess ate a plant shutdown at 2030 on _ May.19, 1990, therefore, NNEC0 respectfull r requests that the waiver of compliance be issued. prior to that time.
Prompt; action is appropriate because failure to act in t timely manner-will impose ~an unnecessary plant shutdown for a-condition 4 iat involves ' minimal safety reduction and, as discussed - below, does not it volve a significant hazards consideration.
Further, the need to request the waiver on an emergency basis could not have been reasonably avoided b4 :ause the problem was uniy;ivuonlly identlPl J nd Aquently the seven day
- 0 uns entapod.-
Backaroynd l
-On May 11, 1990, Northeast Utilities Service Companj (NUSCO) Generatisa Electrical Engineering notified Millstone Unit No. 1 personnel that the preliminary results of a Gas Turbine Generator load sti ly showed that post-9005300038 900521 PDR ADOCK 05000245 P
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U.Si Nuclear Regdlatory CCamission 1
813532/Page-2 h]
May 18, 1990 g
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thar, previously assumed and' ma)/ Loss of Normal Power (LN Loss of Coolant Accident (LOCA
) loading was greater y be beyond the capabiliiy of the Gas Turbine Gererator.
The completion of the load study had bet 'i accelerated at the request of Millstone Unit No. I personnel following the recent Licensee Event Report No. 90 03, regarding the Gas Turbine Generator ld ding and surveillance requirements.
l The increase in postulated load requirements was conser i ntively based on FWCl operation at pump runout conditions with cold water sup ; lied from the Conden-sate Storage Tank.
Follow up preliminary data supplied showed the calculated load requiremen,,to Millstone Unit No.
I on May 12, 1990 to be 11.463 MW. The rating of the Gas Turbine Generator as specified in th Updated Final Safety Analysis Report (UFSAR) is 11.1 MW at 100 degrees F a intake temperature.
General Electric was contacted to obtain an independent : heck througl perfor.
mance of similar load calculations.
Their results wer) provided on May 12, 1990, and were in close agreement with the preliminary h SCO values.
The Millstone Unit No.1 Plant Operctions Review Commit[re(PORC convened on May 12,1990 at 1850 hours0.0214 days <br />0.514 hours <br />0.00306 weeks <br />7.03925e-4 months <br /> to discuss a conservative o urse of) action.The
.PORC agreed that the removal of the fuses that enable J
> hat the Gas Turbine-st-LOCA/LNP start of the FWCI System would be a prudent action to ensure Generator would be available to automatically assume
- ads required for the operation of low pressure Emergency Core Cooling Syst is (ECCS) and support systems.
In accordance with instructions and guidance provided in Operating Procedures and Emergency Operating Procedures, operah ons personnel would retain the flexibility for manually starting FWCl equiplint, while monitoring the Gas Turbine Generator laading.
Operations personU 1 were instructed to limit Gas Turbine Generator loading to approximately 1( MW, the value corre-sponding to the most recently demonstrated loading fci reliable operation.
The present surveillance requires the Gas Turbine Gener ator to be loaded to greater than 10 MW, thereby ensuring operability bahd on exceeding the previous post-LOCA/LNP calculated load of 9.9 MW.
The PORC concluded that this action would not create a iifetyconcerninview of the fact that, although FWCI operation is a part if the Millstone Unit No. I design basis, it is not needed to acceptably a j tigate any accident.
Further, continued plant operation for up to seven daya is presently allowed by Technical Specifications with FWCI inoperable. NRC lls sident Inspectors and Region I personnel were notified of the situation.
SincetherehadbeennoGasTurbineGeneratoroperabilithdemonstrationatthe new load requirement and the Gas Turbine Generator may,iot have been capable of meeting this load at elevated ambient temperatures, c ' May 12, 1990 at 2030 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.72415e-4 months <br />, the Gas Turbine Generator was declared incl irable with its LCO exceeded.
An orderly shutdawn was initiated in acco
' dance with Technical Specifications.
An Unusual Event was also declared, ay I immediate notifica-
. tion in accordance with 10CFR50.72 was made.
Durin the course of plant shutdown, the automatic post-LOCA/LNP start of the FWCI ystem was disabled by removal of the logic system fuses.
This action resul' ed in making the Gas Turbine Generator operable by reducing the post-accidenfloadrequirementsto i
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U.S. Nuclear Regulatory Commission 813532/Page 3 l
May 18, 1990 much less than the capability of the machine.
In supp rt of this end, how-ever, the FWCI System was made inoperable with a seven dj y LCO.
Discussion s
The proposed waiver of compliance is for one-time appre 'al of reactor opera-tion for up to-ten days with FWCI inoperable.
Continue I operation is contin-gent on all active components of the low pressure cooh,nt injection (LPOI)f core spray (CS), isolation condenser (10), and autol iitic pressure relie systems > being operable.
It should be noted that B lt Standard Technical Specifications allow the high pressure injection systen ; to be inonerable for up to 14 days, provided the low pressure systems are ay tilable.
thecurrent Millstone Unit No.1 Technical Specifications allow ret ctor operation for 7 days with FWCI inoperable.
The proposed change will allow up to an additional thf te days to implement I
the following plant modifications ~ to restore FWCI to op i able status.
First the setpoint for switching the feedwater control syst i m from level control (normal configuration) to flow control with one feedi ;ter pump running is gpm) to approximately/
pump being decreased from 115% (9200 4000 -gpm (minimum).
Second, modifications will be made to trip the feed on Gas Turbine Generator high exhaust tem)erature (only when the Gas / Turbine is supplying emergency power to the feec purp), thus preventing the. las Turbine Generator from tripping in the event of a feedwater line break. " n addition, NNECO is pursuing changes to the Gas Turbine Generator solid sh ate governor control logic to allow testing at higher than 10 MW output.
i basis accidents at Notwithstanding the above mentioned changes, all desi Millstone Unit No.1 can be acceptably mitigated assum'}ig no credit for FWCl operation.
With FWCI unavailable for an additional tFI ee days, an accid (nt could still be acceptably mitigated with no significa it increase in conse-quences beyond those already considered.
In addition, io irreversible envi-ronmental consequences will be realized.
The followinf transients and acci-dents were evaluated and are discussed below:
large lid small break LOCA:
inside drywell, high energy line breaks (HELB) outside dt ywell and LNP.
A.
LOCA Inside Drywell 1.
Laroe Break l
During a large break LOCA in the recirculati line, all FWCI flow would spill out through the break.
In fact, ' he design basis LOCA analysis assumes no FWCI flow for the large bf eak.
(Note that this is not the assumed single failure; the limi1 ng single failure is d
the LPCI injection valve).
Therefore, unava ability of FWCI will have no impact on the results of the large bru k analysis, i
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d U.Si Nuclear Regulatory Commission B13532/Page 4 May 18, 1990 2;
Small Braak iSBLOCA)
I' For a SBLOCA..- failure of the Gas Turbine i
, the limiting sinolt failure since it results in a loss of hi< ll
)ressure inject < on capability. -If FWCI were inoperable there w Ialc no longer be any difference between a gas turbine failure and -
i diesel failure.
The reasoning for this conclusion is as follows: g The APR blowdown initiation time (H1 Dryd ll Pressure + Low-Low a.
Water Level + 120 sec.) is much longer than either the Gas-Turbinestarttime(48sec.)ortheDieselstarttime(13sec.)
given an accident s gnal.
b.
Therefore, following a SBLOCA, both CS l i d LPCI pumps will be up to speed and capable of supplying fle i
long before the APR reduces pressure below their shut-off hea ;s.-
c.
Since one train of low pressure ECCS pu l >s (i.e., 1 CS and i LPCI) is powered by the Gas Turbine 1 1ld the _ other by the Diesel, there is no difference between a ias turbine failure or a diesel generator failure.
l Thus, it can be seen that the analysis results:>rovided in the UFSAR will remain valid, and the only change.would' w that-the limiting single failure would be either a gas turbini failure or a diesel generator failure.
However, the consequences iould be unaffected.
B..
HRB Outside Drvwell l
Postulated line breaks outside the drywell includ the IC, Reactor Water Cleanup ' and. Main Steam lines.
These break'1oca ons are analyzed to demonstrate that containment isolation will ade stely limit off-site doses due to the mass released outside containment.
For these scenarios, FWCl operation will increase RPV pressure and. con-tquently increase the mass releases.
With FWCI unavailable, mass releal 's would be decreased and consequently off site doses will be reduced.
!)11owing break isola-tion, the only inventory loss is due to boiloff.
' For 'all breaks except IC line break the IC can be used for core cool ig.
For the 'IC line break, the ope,rator would depressurize and use loi
' pressure systems for core cooling.
It should be noted that even if FWC f were operable, these actions would be necessary to mitigate single fai I ures such as the gas 3
turbine.
I C.
Loss of Normal Powe_ r I
In case of an LNP, FWCI will not be available to re goverandmaintainRPh level. However, the IC will be available.
In thepvent of a failure in the IC, the operator could depressurize the RPV' ind use low pressure (LPCI/CS) pumps for inventory control and core cool ng, i
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U.S'. Nuclear Regulatory Commission B13532/Page5 L
Nay 18, 1990 As discussed above, NNECO will.take compensatory measul ts necessary to miti-L
~ gate the various postulated accidents by manually initi cing FWCI or APR when necessary, as directed by existino plant procedures, onJ ch plant operatory L
are thoroughly trained.
[
NNECO has concluded that the requested relief does not Unvolve a significant hazards consideration in that the waiver of coinpliance w l uld not:
1, Involve a significant increase in the_ probability i >r consequences of an accident previously evaluated.
The waiver will ffect only the time allowed for continued operation with the FWCI syi em inoperable.
This cannot impact the probability of any accident, b.l acceptably mitigated th respect to conse-quences, while all design basis accidents can be even assuming no credit for FWCI operation, it is nl ted that the proposed waiver is not a permanent change but rather a onet,ime extension of the a)plicable LCO requirement.
Since accidents are ty l ically not postulated w111e subject to LCO requirements, the design ba l ls analysis would be unaffected. However, even if an accident were post lated to occur during the proposed extension,. it could still be accepts l ly mitigated with no signuficant increase in consequences beyond thos I
already considered.
NNECO has-evaluated this change from a Probab( istic Risk Analysis pewspee44ve and has deaewm4med akaa ahe impac4 e i
sepe melt opequeney would be less than 1% for up to a seven day extensi : n.
2.
Create the possibility of-a new or different ki l d of accident.
The proposed change can have no impact on the possibilf l y of a new or differ-ent initiating event.
Additionally, the occurrene of any design basis accident during the time FWCI is unavailable w 1 not result in an o
accident that is significantly different than w( nt has already been considered.
3.
Involve a significant reduction in any margin of saj ety. The change will have no significant impact on the consequences ofl.ny accident and will have no impact on any protective boundary.
In summary, the waiver of compliance would provide a' one-time approval of The waiver of compliance would extend the existing 1.00).
reactor operation for up to an additional three days ith FWCI inoperable.
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- hrough May 22, 1990.
l Continued operation is contingent on the diverse low prp ;sure systems, It and APR being available.
The intent of this change is con,I stent with BWR Stan-p dard : Technical Specifications which allow the high pre l Lure i tjection system to be inoperable for up to 14 days, provided the lowy premn systems are o
avail able. The waiver of compliance will allow up to af addition)1 three days to enable safe im)1ementation of plant modifications to rettore FWCI to operable status, dith FWCI unavailable for an addii! onal inree days, an L
accident can still be acceptably mitigated with no si nificant increase in consequences beyond those already considered.
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U.S. Nuclear Regulatory Commission
_B13532/Page 6 May 18, 1990 The Millstone Unit No.1 PORC and Nuclear Review Boa Wd have a> proved this request for a temporary waiver of - compliance and d ncur witi the abovel determinations.
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We wish to emphasize our conclusions that this propose l request for a tem >o-rary waiver involves no undue safety risk.
We are thshfore requesting ttis action to allow continued plant operation, as ther61 is no safety -issue threatening safe plant operation, j
We believe the above information provides a complete bai' s for approval of the requested temporary waiver of compliance from Technical '.pecification 3.5.C.3.
We will continue to keep you informed on matters releva to this request.
Should the Staff require any additional information to Irocess this temporary waiver of compliance on an expedited basis, NNECO remaid available to provide such information promptly.
Very truly yours, NORTHEAST NUCLEAR ENI I;GY COMPANY N b"' '*
FOR:
E. J. Mroczka Senior Vice Prei dent BY:
W. D. Romberg 1 -
Vice President cc:
M. L. Boyle, NRC Project Manager, Millstone Unit Nd 1
A. B. Wang, NRC Project Manager, Haddam Neck Plant {t W. J. Raymond, Senior Resident Inspector, M111ston Unit Nos. 1, 2, and 3 Mr. Kevin McCarthy f
Director, Radiation Control Unit a
Department of Environmental Protection Hartford, Connecticut 06116 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 l
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