ML19210B098
| ML19210B098 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/07/1977 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19210B096 | List: |
| References | |
| NUDOCS 7911040040 | |
| Download: ML19210B098 (4) | |
Text
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UNITED STATES j
NUCLEAR REGULATORY COMMISSION y
W ASHINGTON. D. C. 205$b
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%,a.09 SAFETY EVALUATION BY THE OF: ICE OF NUCLEAR REACTOR REGULAT AMENDMENT NO. 25 TO FACILITY OPERATING LICENSE NO. DPR-50 METROPOLITAN EDISON COMPANY JERSEY CEf4 TRAL POWER ED LIGHT COMPANY PEN!!SYLVAMA ELECTRIC COMPAf;Y THREE MILE ISLAND NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-289 Introduction Three Mile Island Nuclear Station, Unit No.1 (TMI-1) comenced Cycle 2 By phone call on June 4, 1976 and by letter 24, 1976.
operation on May Metropolitan Edison Company (Meted) informed us of dated June 5, 1976, the improper incorporation of fuel densification pencities into both the TMI-1 Cycle 2 Reload Report submitted FebrLary 11, 1976 and the resultent 18, 1976. Meted also stated TMI-1 Technical Specifications issued May that this error could be more than corrpensated for by taking credit for elimination of a currently assumed internals vent valve flow penalty.
By letter dated July 7,1976, Meted submitted a Technical Specification This request e., modified by Meted's letters dated change request.
October 19, 1976 and January 31, 1977. This change will properly incorporate densification and rod bowing penalties, eliminate the vent vent valve surveillance requirements.
valve penalty and incorporate Evaluation _
10, 1976, we informed Meted that, based on our By letter dated March review of the Babcock & Wilcox (BAW) report "B&W Operating Experience of Reactor Internals Vent Valves," we concluded that vent valves on ELW plants will remain closed durino normal operation a The not include a vent valve flow penalty in their safety analysis.
necessary surveillance requirement is a check of the vent valves each refueling outage to confirm that none are stuck open and that each Based on this previous evaluation, exhibits freedom of movenent.
an enclosure to our March 10 letter, we conclude that elimination of the 4.6% internals vent valve flow penalty for TMI-1 is ac~eptable.
15v3 194 N9110ao Q In addition, we have determined that, due to the assumption in the Final Safety Analysis Report (FSAR) that these valves do operate, the Technical Specifications of B&W facilities should require should be included for the furces, as specified in the FSAR, necessary Since the specifications associated with to operate the vent valves.
elimination of the vent valve penalty are closely related to these operability requirements, a change to the proposed vent valve surveillance requirements, to satisfy both areas, has been discussed with and agreed to by Meted.
In their July 7,1976, submittal Meted states that the error found in the TMI-1. Cycle 2 departure from nucleate boiling ratio (DNBR) densification p(enalty calculations resulted from the use of incons fiux shape) and enthalpy rise in evaluating the DNBR densificatien penalty This error only affects the pressure-temperature envelope and flux /ficw Meted also states that a revised densification analysis indicates that the correct penalities are 5.93'; DNBR (versus 1 ratio.
the Reload Report). Tne proper incorporation of densification penalties will tend te eake affected limits, i.e. flux-flow and variable low pressure trip setpoints, more restrictive.
Recently, Westinghouse Electric Corporation presented data to the NRC staff which showed that previously developed methods for accounting
'for the 'effect of fuel rod bowing on departure from nucleate boiling may not contain adecuate themal margin when unheated rods (such as thicule We have evaluated the impact of the Westinghouse data tube:) are present.
Models for treating en all operating pressurized water reactors (PWR's).
the effects of fuel rod bowing on themal-hydraulic perfomance have been The models are based on the propensity of the derived for all PWR's.
individual fuel designs _ to bow and on the thermal analysis methods used to predict tne coolant conditions for both nomal operation and dati:ipatcc transients.
We have reviewed the extent of rod bowing which occurs with B&W fuel.
Based on this review, an equation was derived for the clearance re-duction between fuel rods due to fuel rod bowing as a function of burnup:
f = a + b diIT Co where f is the fractional amount of closure Co Bu is the b ndle average burnup, and a,b are empirical constants fitted to B&W rod bow data.
The reduction in DNBR due to fuel rod bowing is a.sumed to vary linearly with the reduction in clearance between the fuel rod For B&W reactors the ONBR penalty factor used in the thermal analysis.
for end of third cycle has been calculated to be 11.2% DNBR.
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. By letter dated October 19, 1976, Meted presented their available margins to offset the DNBR rod bow penalty for TMI-1. The total margin after correction of the densification penalty and elimination of the vent valve penalty, as discussed above, is 15.5% DNBR. We agree with the available margins as presented by Meted and therefore conclude that no reduction in DNBR due to rod t,owing effects is required.
The variable low oressure trip setpoint for cycle 2 operation is based on the pressure-temperature limit curve for four pump operation shown as Curve 1 This curve currently incor-in Figure 2.1-3 of the Technical Specifications.
porates the open vent valve penalty. Curves 2 and 3 represent the correspond-and do not. incorporate ing limits for 3 and 2 pump operation, respectively,ification and rod bow Proper incorporation of dens the vent valve penalty.
penalties makes these curves more restrictive; however, taking credit for The sumation elimination of the vent valve penalty has t1e opposite efect.
of imposed penaltias and available margins, as discussed above, results in Curve 1 remaining the same as is currently.n the Technical Specifications.
The Accordingly, the variable low pressure tr'p setpoint remains the same.
revised Curves 2 and 3 have incorporated ohly the rod bow and densification penalties and, therefore, have moved to the left (more restrictive).
We conclude that the existing four pump pressure-temperature curve and variable low pressure trip setpoint are correct considering proper incor-poration of densification and rod bow penalties and elimination of the Furthermore, we conclude that the revised pressure-vent valve penalty.
temperature curves for two and three pump operation indicate the corrected pressure-temperature relationship and are acceptable.
The current flux / flow trip setpoint for Cycle 2 is 1.08.
Meted has demonstrated that when the correct densification and rod bow penalties are incorporated and the vent valve penalty is eliminated, the thermal-This value hydraulic limiting flux / flow setpoint is greater than 1.12.
must be 1.11 or greater to justify the trip setpoint of 1.08; therefore, we conclude that the flux / flow trip setpoint of 1.08 in the current Technical Specifications is acceptable.
Presently TMI-1 is operating with Technical Specifications made conservative by taking credit for elimination of the vent valve penalty in conjunction with correcting densification and rod bow penalties. These corrections, however, are not a part of the analyses upon which the current Technical Specifications are based. The proposed change will correct these analyses by properly incorporating densification and rod bow penalties, eliminating the vent valve penalty, and adding vent valve surveillance requirements which we have previously found to be an acceptable alternative to incorporating a vent valve flow penalty.
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. We have determined that the amendment does not authorize a change in effluent types or total asunts nor an increase in power level and will not result in any significant environn. ental impact. Having made this deternination, we have ttrtner ccr.cluced tiet the amendc.ent involves an action which is in-significant from the standpoint of envircnmental impact and pursuert to 10 CFR 151.5(d)(4) that an envirer.. entsl impact staterrent, or negative declarction m
and enviror. rental impact appraisal need not be prepared in connection with the issuance of this amendr.ent.
Cenclusion We have concluded, based on the considerations discussed above, that:
(') there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed nanner, and (2) such activities will be conducted in ccmpliance with the Cec.ission's regulations and the issuance of this atencment will not be inimical to the corr.on defense and security or to the health and safety of the public.
Dated: March 7, 1977 7
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UNITED STATES NUCLEAR REGULATORY COMt11SSION COCKET NO. 50-289 METROPOLITAN EDIS0N COMPANY JERSEY CENTRAL POWER AND LIGHT COMPANY PENNSYLVANIA ELECTRIC COMPANY NOTICE OF ISSUANCE OF AMENDMENT TO FACILITY OPERATING LICENSE The U. S. Nuclear Regulatory Comission (the Commission) has issued Amendment No. 0
- to Facility Operating License No. DPR-50, issued to Metropolitan Edison Company, Jersey Central Power and Light Company, and Pennsylvania Electric Company (the licensees), which revised Technical Specifications for operation of the Three Mile Island Nuclear Station, Unit No.1 (the facility) located in Dauphin County, Pennsylvania. The amendment is effective as of its date of issuance.
The amendment incorporates into the Three Mile Island, Unit No. 1 Technical Specifications revised pressure-temperature curves for two and three pump operation and reactor internals vent valve surveillance requirements.
The application for the amendment complies with the standards ard renuirements of the Atomic Ener; 'ct of 1954, as amended (the Act), and the 'Connission's rules and regulations. The Commission has made appropriate findings as required by the Act and the Commission's rules and regulations in
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. Notice of 10 CFR Chapter I, which are set forth in the license amendment.
Proposed Issuance of Amendment to Facility Operating License in connection with this action was published in the FEDERAL REGISTER on August 5,1976 (41 F.R. 32800). No request for a hearing or petition for leave to intervene was filed following notice of the proposed action. Contrary to the license amendment proposed in the above-mentioned Notice, this action does not change the variable low pressure trip setpoint.
The Comission has determined that the issuance of this amendment wil not result in any significant environmental impact and that pursuant to 10 CFR iS1.5(d)(4) an environmental impact statement, or negative declaration and environmental impact appraisal need'not be prepared in connection with issuance of this amendment.
For further details with respect to this action, see (1) the application for amendment dated July 7,1976, as supplemented October 19, 1976 and January 31,1977,(2) Amendment No. 25 to License No. DPR-50, and (3) the Comission's related Safety Evaluation. All of these items are available for public inspection at the Comission's Public Document Room,1717 H Street, N.W., Washington, D.C. and at the Government Publications Section, State Library of Pennsylvania, Box 1610 (Education Building), Harrisburg, Pennsy? ania.
A copy of items (2) and (3) may be obtained upon request addressed to the U. S. Nuclear Regulatory Comission, Washington, D.C.
20555, Attention:
Director, Division of Operating Reactors.
Dated at Bethesda, Maryland, this 7th day of March-1977.
FOR THE NUCLEAR REGULATORY COPJilSSION h.
Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors 1533 199