ML20057A832

Safety Evaluation Supporting Amend 178 to License DPR-50

ML20057A832
Person / Time
Site:	Crane
Issue date:	09/10/1993
From:	Office of Nuclear Reactor Regulation
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ML20057A831	List: ML20057A830 ML20057A832
References
NUDOCS 9309150395
Download: ML20057A832 (4)

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UNITED STATES l

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1 i t NUCLEAR REGULATORY COMMISSION l

W ASmCTOR D C. MSAd I

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i

REL ATED TO AMENDMENT NO. 2' TO FACILITY OPERATING LICENSE NO. DPR-50 I

l METROPOLITAN EDISON COMPANY JERSEY CENTRAL POWER & LIGHT COMPANY f

l PENNSYLVANIA ELECTRIC COMPANY GPU NUCLEAR CORPORATION I

f THREE MILE ISLAND NUCLEAR STATION. UNIT NO. 1 1

DOCKET NO. 50-289

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1.0 BACKGROUND

i By letter dated June 7,1993 (Ref.1), GPU Nuclear Corporation (GPUN/

i licensee), submitted a request to the U.S. Nuclear Regulatory Commission (NRC) l for changes to the Three Mile Island Nuclear Station, Unit 1 (THI-1) Technical l

Specifications (TS).

The changes would permit (1) the use of gadolinia-urania integral burnable poison fuel pellets in the THI-l reactor, and (2) the replacement of the existing list of NRC-approved analytical methods used to 3

determine core operating limits with methodologies contained in Topical Report i

BAW-10179P, which was recently approved by the NRC (see Ref. 2).

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The licensee also requested changes to TS section 3.3.1.1.a to reflect the increase in the minimum required concentration of baron in the Borated Water i

3 Storage Tank (BWST) from 2270 parts per million (ppm) to 2500 ppm.

Pertinent j

bases are revised to clarify the criteria for establishing the BWST boron concentration limit and the acceptable pH range in the reactor building spray j

j and sump.

The bases are also revised to correctly reference the peak cladding l

l temperature limit of 2200 F instead of 2300 F, as required by section 50.46 of title 10 of the Code of Federal Regulations (10 CFR).

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2.0 EVALUATION i

j 2.1 Use of Gadolinia Burnable Poison i

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TMI-l is designed to operate for 646 15 effective full power days (EFPDs).

Extended cycles are planned for a nominal length of 650 EFPDs.

Typically, extended cycles require more highly enriched fuel which generates higher 1

peaking factors.

The use of gadolinia will enhance the control of assembly l

power peaking, thus ensuring fuel design criteria and requirements are satisfied.

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Babcock and Wilcox Fuel Company (BWFC) has performed extensive evaluations of the use of gadolinia as a burnable absorber, and has submitted reports of these evaluatior.s to the NRC for approval.

The NRC staff has reviewed these a

reports and found them acceptable (Refs. 2/3/4).

The reports contained bench-l marked analytical tools to address neutronics and thermal-hydraulic l

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characteristics associated with the use of gadolinia in fuel design.

They also contained methodology applicable in pressurized water reactor licensing I

applications, including reload physics analysis, core physics test manuals, i

safety analyses, and startup predictions.

l The NRC staff has found Topical Report BAW-10179P acceptable for referencing

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j in license application (Ref. 2).

Specifically, in Reference 2, the NRC stated j

that the " Core Operating Limits Report (COLR) limits may be established and modified using the approved methodologies identified in Ref. 2.

Licensees of B&W-designed plants may reference the approved Topical Report (BAW-10179P) in the reporting requirements section of their technical specifications in place 4

of the references stated above." The " references stated above" are the 18 i

references listed and include the 12 references contained in THI-l Technical i

Specification Section 6.9.5.2.

BAW-10179P also includes references to the i

computer code NEMO that the licensee intends to use in the Cycle 10 Reload Design and for future cycles designed by B&W. Thus, NRC-approved Topical Report BAW-10179P will be used in calculation of COLR parameters and l

3 establishes BWFC methodology for cycle reloads.

l 2.2 Revised Boron Concentration Reauirements

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2.2.1 Revision of TS Section 3.3.1.1.a Current TMI-l Cyr e 10 (and future cycles) will require higher boron i

concentrations.

This is due mainly to utilization of more highly enriched i

j fuels.

The minimum BWST boron concentration specified in TS 3.3.1.1.a is 2270 ppm.

Cycle 10 core design calculations by the licensee showed that the minimum concentration must be increased to at least 2462 ppm.

The licensee will use a value of 2500 ppm to provide additional conservatism as well as flexibility for future cycles.

This value is well below the precipitation i

limit of 5250 ppm at 40 F, and the existing minimum TS temperature limit of i

40 F is not affected. Analysis by the licensee showed that this change will l

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ensure that during normal operation, the BWST baron concentration will be l

l sufficient to produce a boron concentration in the reactor building sump that j

will maintain the reactor at least one percent subtritical following a j

postulated loss-of-coolant accident. The revised BWST boron concentration i

analysis was subject to assuming the Core flood Tank boron concentration to be l

j at the minimum value of 2270 ppm currently specified in TS section 3.3.1.2.

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Further analysis by the licensee also showed that the existing requirements for the boric acid mix tank (TS section 3.2), the reclaimed boric acid storage tank volume, and the concentration limits continue to ensure adequate boration under all operating conditions, thus ensuring the capability to bring the reactor to a cold shutdown condition.

4 2.2.2 Administrative Revisions to TS 3.3 Bases The licensee revised the TS 3.3 bases to clarify the criteria for establishing j

the BWST boron concentration limit and the acceptable pH range for the reactor building spray and sump inventory. The licensee analyzed the effects of l

increased boron concentration in the BWST. The analyses consisted of determining the potential impact on the pH values for the reactor building i

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spray and reactor building sump inventory following a design-basis accident.

l The analyses assumed that the sodium hydroxide tank level and the volume of 4

the BWST were to be at the existing levels required by the TS.

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Failures that could result in the maximum and minimum pH conditions were j

analyzed; results of the analysas were used to calculate the reactor building l

spray and sump pH.

The analyses showed that the reactor building spray and l

final equilibrium sump pH is within the acceptable range of 8.0-11.0.

The i

licensee analyzed the potential effect of reducing the pH level from 8.5 to l

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8.0 on material compatibility, equipment qualification, and of fsite dose l

j consequences.

The analyses showed that maintaining the pH level above 7.0 is adequate to inhibit initiation of stress corrosion cracking Of austenitic j

stainless steel within the reactor coolant pressure bound &ry.

The results of these analyses are consistent with NRC Standard Review Plan section 6.1.1, and j

the review of the material properties of exposed equipment indicated that the l

likelihood of component failure will not increase.

Consequently, a change in the minimum pH will have no effect on material and fluids compatibility, l

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equipment qualification criteria, or the potential for baron precipitation.

The licensee also reviewed the potential impact of the change in pH level on

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the previously analyzed dose consequences of the postulated design-basis 1

maximum hypothetical accident (MHA).

To assess these dose consequences, the L

I licensee used methodology that adhered to ANSI /ANS 56.5-1079 Standard for "PWR and BWR Containment Spray System Design Criteria." The analysis showed that l

the dose consequences are bounded by the existing MHA analysis and are well q

below the guidelines of 10 CFR Part 100.

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3.0

SUMMARY

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The staff has reviewed the licensee's proposed TS changes to reflect the inclusion of gadolinia-uranii in the fuel rod design description and of i

revised boron concentration requirements and clarification of bases.

The f

staff concludes that the proposed changes satisfy its positions and i

requirements in these areas, and, therefore, are acceptable.

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4.0 REFERENCES

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Letter from T. G. Broughton, GPU Nuclear Corporation, to the NRC, j

dated June 7, 1993..

2.

Letter from A. C. Thadani, NRC, to J. D. McCarthy, March 16, 1993.

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Letter from A. C. Thadani, NRC, to J. H. Taylor, January 29, 1993, i

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Letter from A. C. Thadani, NRC, to J. H. Taylor, June 24, 1993.

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5.0 STATE CONSULTATION

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In accordance with the Commission's regulations, the Pennsylvania State I

official was notified of the proposed issuance of the amendment.

The State l

l official had no comments.

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6.0 ENVIRONMENTAL CONSIDERATIQN 1

The amendment changes a requirement with respect to installation or use of a l

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facility component located within the restricted area as defined in 10 CFR Part 20.

The NRC staff has determined that the amendment involves no i

significant increase in the amounts, and no significant change in the types, l

of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation f

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 (58 FR 42352). Accordingly, the amendment i

meets the eligibility criteria for categorical exclusion set forth in 10 CFR i

51.22(c)(9).

Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of a

the amendment.

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7.0 CONCLUSION

The Commission has concluded, based on the considerations discussed abovi-

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that:

(1) there is reasonable assurance that the health and safety of the j

public will not be endangered by operation in the proposed manner, (2) such i

j activities will be conducted in compliance with the Commission's regulations, i

and (3) the issuance of the amendment will not be inimical to the common i

defense and security or to the health and safety of the public.

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Principal Contributor:

A. Attard I

Date: Septenber 10, 1993 i

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