ML20077N178

Application for Amend to License DPR-50,consisting of Tech Spec Change Request 208 Re Max Allowable Linear Heat Rate Limits & Borated Water Storage Shutdown Margin Bases

ML20077N178
Person / Time
Site:	Three Mile Island
Issue date:	08/09/1991
From:	Broughton T GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20077N174	List: ML20077N169 ML20077N178 ML20077N184
References
NUDOCS 9108140242
Download: ML20077N178 (6)

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• METROPOLITAN EDISON COMPANY JERSEY CENTRAL POWER AND LIGHT COMPANY AND PENNSYLVANIA ELECTRIC COMPANY THREE MILE ISLAND NUCLEAR STATION, UNIT 1 Operating License No. DPR-50 Docket No. 50-289 Technical Specification Change Request No. 208 This Technical Specification Change Request is submitted in support of Licensee's request to change Appendix A to Operating License No. DPR-50 for Three Mile Island Nuclear Station, Unit 1. As a part of this request, proposed replacement pages for Appendix A are also included.

GPU NUCLEAR CORPORATION BY:

Vice Presid@t and Director,1MI-l Sworn to beforeand mesubscribeA'A this Y6 day of d a mu d , 1991.

Mpfh $5 HL if '

Notsry Public T Dagtm ef sca - w m v.an w perspavahademen d Natutz bI $bhk$N

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UNITED STATES OF f,MERICA

-NUCLEAR-REGULATORY COMMISSION IN THE HATTER OF DOCKET NO. 50-289 GPU NUCLEAR CORPORATION LICENSE N0. DPR-50 CERTIFICATE OF SERVICE This f s to certify that a copy of Technical Specification Change Request No. 208 to Appendix A of the Operating License for Three Mile Island Nuclear Station Unit 1, has, on the date given below, been filed with executives of Londonderry Township, Dauphin County, Pennsylvania; Dauphin County, Pennsylvania; and the Pennsylvania Department of Environmental Resources, Bureau of Radiation Protection, by deposit in the United States mail, addressed as follows:

Mr. Jay H. Kopp, Chairman Ms. Sally S. Klein, Chairman Board of Supervisors of Board of County Commissioners Londonderry Township of Dauphin County R.D. #1 Geyers Church Road Dauphin County Courthouse .

Middletown, PA 17057 Harrisburg, PA 17120 Mr. Thomas Gerusky, Director-PA. Department of Environmental Resources Bureau of Radiation Protection P.O. Box 2063 Harrisburg, PA 17120 GPU NUCLEAR CORPORATION

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BY: N' b Vice Presiden a W ijrector, THI-l DATE:  ?/"l / 9 8

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I. Technical Specification' Chance Reouest (TSCR) No. 208 y

GPUN requests that the following changed replacement pages be inserted '

-into the existing Technical Specifications: i Revised page: 3-20 Revised Figure: 3.5 - 2M These pages are attached to this change request.

-11. -Rgason For Chance Technical Specification Figure 3.5-2M is revised to reflect the Babcock &

Wilcox (B&W) reevaluations of the generic LOCA linear heat rate-(LHR) allowable limits. Penalties are imposed at the 6-foot core height elevation (16.5 kw/f t reduced to 16.1 kw/ft at beginning-of-cycle and 18,0 kw/ft reduced.to 16.1 kw/ft at 1000 MWD /MTU). The LOCA linear heat rate limits for the 4-foot beginning-of-cycle (BOC) limit, and the 4-foot and  ;

2-foot 1000 MWD /MTU limits have been reconfirmed using the NRC approved '

TACO-3 fuel code as input to the ECCS analysis. Application of TACO-3 results in additional end-of-life (E0L) linear heat rato limits at higher burnups for all core elevations and fuel designs.

Technical Specification Section 3.2 Bases is administratively revised to delete reference to a 10% safety factor for minimum volume of boric acid solution, and to incorporate a larger bounding value for borated water storage tank volume consistent with the higher U235 core enrichments planned for the future.

III. Safety Evaluation Justifyina Chanae Changes in the B&W ECCS analysis models and inputs have resulted in new ,

LOCA LHR Kw/ft limits at beginning and end-of-cycle to assure preservation of the Acceptance Criteria of 10 CFR 50.46. Specifically, the LHR limits at the 6-foot elevation are reduced from 16.5 to 16.1 Kw/ft at 80C (0 to 1000 MWD /MTU) and from 18.0 to 16.1 Kw/ft for burnups above 1000 MWD /MTU; at- E0C LHR limits are reduced at all elevations as a- function of burnup from 36,375 to 60,000 MWD /MTU to assure that internal fuel rod pressure does not exceed RCS pressure. Technical Specification Figure 3.5-2M has been revised to reflect these limits changes and to provide a clarified format.

The-revised THI-l generic LOCA LHR limits have been established using B&W's approved updated ECCS Evaluation Model (EM) (Ref.1) and fuel performance codes, TACO-2 (Ref. 2), and TACO-3 (Ref. 3) for LOCA initialization. The revisions have resulted from reevaluations of the LHR limits due to transition from the Mark B to the Mark BZ fuel assembly with Zircaloy intermediate grids, to use of the BWC CHF correlation in place of the BAW-2 and to the FLECSET reflood heat transfer model modification made to the EM. Preliminary results of these reevaluations were documented to l the USNRC in References 4 and 5 because the peak clad temperature (PCT) results at the 2 and 4-foot elevations reflected changes of greater than 50*F from those previously calculated. Reference 4 confirmed that review of previous evaluations of the LHR limits at the 2, 8 and 10-foot elevations showed that these evaluations would not be significantly affected by the model changes described above and that these limits continued to provide sufficient margin to the PCT Acceptance Criteria.

The 2, 8 and 10-foot limits were established in Reference 6 as modified at the 2-foot level by Reference 7 and approved in Technical Specification Amendment No. 152 for TMI-1.

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References 4 and 5 documented that the revised PCT values at the 6 and 4-foot levels, respectively, both met the Acceptance Criteria using the current LHR limits. However, because the margins were small and because the burnup benefits at 1000 MWD /MTV could no longer be supported generically, further evaluations were performed at these elevations. For the 6-foot analysis-the allowable LHR was reduced to 16.1 Kw/ft from 16.5 Kw/ft and analyzed using the updated EM initialized with the TACO-2 fuel

, code. Results.gave a maximum PCT of 2073*F. This is a change of greater l than 50*F for those reported in Reference 4 (2194*F) but less than 50*F l for those reported in Reference 6 (2108'F). The new 6-foot result is well l within the 2200'F criteria. However, because the controlling PCT occurs for the unruptured cladding node, the burnup benefit in the current-LHR limits at 1000 MWD /MTV (increase to 18.0 Kw/ft) could not be justified.

Therefore, to assure conservatism the allowable 6-foot LHR limits at B0C and 1000 MWD /MTV are both reduced to 16.1 Kw/ft.

In order to avoid potential restrictions on current core operating limits (i.e., control rod insertion and axial power imbalance limits) it was desirable to maintain the current 4-foot allowable LHRs. B&W performed a new BOC analysis at the 4-foot level using the current 16.1 Kw/ft LHR limit with the recently-approved TACO-3 fuel model to initialize the updated ECCS EM. TACO-3 was approved by the USNRC for LOCA analysis applications in 1989 (Ref. 8). The code provides lower fuel temperatures, thus lower expected PCTs. Results of the TACO-3 based analysis gave a maximum PCT of 1786*F, well within the 2200*F criteria. This is a change of greater than 50*F from the results of Reference 5 (2160*F) and Reference 6 (1943*F). To verify the current allowable LHR increases at p 1000 MWD /MTV at the 2 and 4-foot elevations, B&W performed additional l time-in-life calculations using TACO-3 for 15.5 Kw/ft and 16.6 Kw/f t, i

respectively. Results gave maximum PCTs of 1828'F-at 2-feet and 1978*F at 4-feet, both well within the 2200*F criteria. Thus, the LHR increases at 1000 MWD /MTV for the 2 and 4-foot levels can be maintained, l'

These evaluations of the revised generic allowable LOCA LHR limits for the B&W 177FA lowered-loop plants at BOC and MOC (1000 MWD /MTV) have confirmed the preservation of the Acceptance Criteria. The changes effectively provide additional margin to the PCT limit.

l l Application of TACO-3 causes a new restriction on end-of-life LOCA LHR limits. B&W fuel rod internal pressure is required to remain below Reactor Coolant System pressure throughout its lifetime. Restrictions on approved TACO-3 applications and uncertainties imposed on best-estimate results cause the rod internal pressure for LOCA initialization conditions to reach system pressure at burnups much earlier in life than previous TACO-2 results. In order to maintain rod pressures below system pressures for higher burnups, the allowable end-of-life LOCA LHR limits for all L elevations must be reduced accordingly based on the burnup of the limiting l fuel rods. This effect is shown on the proposed revised Technical Specification Figure 3.5-2M as a diagonally-decreasing limit as a function of maximum rod average burnup from 36,375 to 60,000 MWD /MTV. These results are generic and applicable to Cycle 8 and future cycles.

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The reduced- E0L LHR limits have been evaluated for potential impact on- the Cycle 8 core operating limits (control rod insertion and axial power imbalance) . Cycle 8 contains some fuel that will intersect the pin pressure limit line of Fig. 3.5-2M. Thus, the allowable LHRs for this fuel must be reduced accordingly. Review of worst-case E0C-8 core power distributions has confirmed that sufficient margin is maintained to the LHRs. .Therefore, the reduced LHRs have no affect on. existing operating ,

' limits. A similar evaluation will be performed for all future cycles l utilizing the TACO-3 based ECCS evaluation. The TACO-3 E0L limits also l have been confirmed to bound all Mark B fuel assembly designs.

Technical Specification Section 3.2.2 requires the boric acid mix tank and the reclaimed boric acid storage tank to each contain the equivalent of 906 ft' of 8700 ppm boron as boric acid solution. The Technical Specification Bases state that this minimum vnlume includes a 10% safety factor and is sufficient to borate the RCS to a 1% subtritical margin in the cold condition at the worst time in core life with a stuck control rod

-assembly. The bases also state that the same shutdown margin requirement can be achieved using 40,000 gallons of 2270 ppm boron as boric acid solution in the borated water storage tank. The "10% safety factor" noted in the Technical Specification Bases was added to early methods of establishing boron requirements which evaluated only a few points in the p cycle for shutdown margin. The 10% factor simply bounded the uncertainty of using a small number of points. B&W has developed better methods that use more data points over the cycle sufficient to eliminate the need for the 10% factor. The new method is applicable to THI-1.

To assure that the Bases contain a bounding minimum boron volume for the BWST consistent with planned higher U235 core enrichments, the current 40,000 gallon value is increased to 60,000 gallons. This volume is provided for information only and is not related to any existing Technical Specification requirement. Further, Technical Specification Section 3.3.1.1 bounds this value by specifying that the borated water storage tank-shall contain a minimum volume of 350,000 gallons of water having a minimum concentration of 2270 ppm boron to ensure that a sufficient supply of borated water is available to satisfy the ECCS requirements.

Therefore, this change is considered administrative.

IV. No Sianificant Hazards Considerations GPUN has determined that this Technical Specification Change Request involves no significant hazards consideration as defined by NRC in 10 CFR 50.92.

1. Operation of the facility in accordance with the proposed amendment would not involve a significant increase in the probability of occurrence or the consequences of an accident previously evaluated.

The proposed change to Technical Specification Figure 3.5-2M incorporates allowable LOCA linear heat rate limits which continue to preserve peak clad temperature and ECCS acceptance criteria. The revised linear heat rate limits are more restrictive than the existing limits at the 6-foot elevation beginning-of-cycle and at end-of-life for all core elevations. The proposed BWST Technical Specification Bases changes are administrative in nature.

Therefore, operation in accordance with the proposed amendment does not involve a significant increase in the probability of occurrence or the consequences of an accident previously evaluated.

2. Operation of the facility in accordance with the proposed amendment would not create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed change to Technical Specification Figure 3.5-2M incorporates conservative adjustments to existing analyses. Peak clad temperature and ECCS acceptance criteria are preserved. The proposed BWST Technical Specification Bases change is administrative in nature. Therefore, operation of the facility in accordance with the proposed amendment would not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Operation of the facility in accordance with the proposed amendment would not involve a significant reduction in a margin of safety.

The proposed change incorporates LOCA linear heat rate limits which preserve the peak clad temperature and ECCS acceptance criteria using approved methodologies. The proposed borated water storage Technical Specification Bases change is administrative in nature.

Therefore, it is concluded that operation of the facility in accordance with the proposed amendment does not involve a significant reduction in a margin of safety.

The Commission has provided guidelines pertaining to the application of the three standards by listing specific examples in 48 FR 14870. The proposed amendment is considered to be in the same category as examples (i) and (ii) of amendments that are considered not likely to involve significant hazards consideration in that the proposed change to the Technical Specification Bases constitute purely an administrative change, and that the proposed change to Technical Specification Figure 3.5-2M constitute additional limitations and restrictions on LOCA linear heat rate allowable limits. Thus, operation of the facility in accordance with the proposed amendment involves no significant hazards considerations.

V. Implement ation It is requested that the amendment authorizing the change become effective upon issuance.

References

1. BAW-10104PA, Rev. 5, "B&W ECCS Evaluation Model," November,1988.

2. BAW-1775, Rev. 0, " TACO-2 Loss-of-Coolant Accident Limit Analysis for 177-F.A lowered Loop Plants," February,1983.

3. BAW-10162 P-A, " TAC 00 Fuel Pin Thermal Analysis Computer Code," November, 1989.

4. BWNT Letter, JHT/90-43, J. H. Taylor to T. E. Murley (NRC), March 19, 1990.

5. EWNT Letter, JHT/90-126, J. H. Taylor to T. E. Murley (NRC), August 23, 1990.

6. BAW-1915 PA, Rev. O, " Bounding Analytical Assessment of NUREG-0630 Models on LOCA Kw/ft Limits with Use of FLECSET," November, 1988.

7. BAW-200lP, " Low Prepressure fuel Rod Program: Burnup Extension LOCA Analysis," June,1987.

8. USNRC "SER for Topical Report BAW-10162P " TACO-3 fuel Pin Thermal Analysis Computer Code," August 14, 1989.