ML20011E277
| ML20011E277 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/01/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20011E273 | List: |
| References | |
| NUDOCS 9002130072 | |
| Download: ML20011E277 (4) | |
Text
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' NUCLE AR REGULATORY COMMISSION - i t WASHlWGTON, D. C. 20666 g ....+ _ SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.152T0 FACILITY.0PERATING LICENSE NO. DPR ' w METROPOLITAN EDISON CONPANY JERSEY CLNIMA. POWER & l.15NT COMPANY PENNSYLVANIA ELEGTRLC COMPANY GPU NUGLEAR.CORPURATION - THREE. MILE ISLAND NUCLEAR-STATION, UNIT NO. 1 { DOCKET NO. 50-289 INTRODUCTION By letter dated October 4,1989, GPU Nuclear Corporation (GPU), the licensee, submitted the following proposed Technical Specification changes for 1MI-1: (1) Themoderatortemperaturecoefficient(MTC)specifiedinTechnicg1 Specification Sectiog 3.1.7.2 would be increased from +0.5 x 10' delta k/k/*F to +0.9 x 10- delta k/k/*F at power levels less than or equal to l-95 percent of rated power. The MTC would still be required to be non-positive at power levels above 95 percent of rated power. L '(2) Theboricacidsolutionvolumeintheboratedwaterstoragetank(BWST) ~ for emergency shutdown requirements specified in' Technical Specification Section 3.2 Bases would be increased from 32,112 gallons to 40,000 gallons. (3) Technical Specification Section 3.5.2.4.f would citrify that the " maximum" tilt limit specified in the Core Operating Limits Report (COLR) l shall be used to comply with this specification. l~ -(4) Technical Specification figure 3.5-2M would reflect an increase in the l allowable linear heat rate (LHR) limitt at the 2-foot elevation from 14.0 to 14.5 kw/ft for 0 to 1000 MWD /MTV and from 15.0 to 15.5 kw/ft af ter 1000 MWD /MTU. ] L (5) Reference to a specific value for the refueling boron concentration would j l be removed from the Bases of Technical Specification Section 3.8. EVALUATION M12 The most limiting accident adversely affected by the positive MTC is the startup accident in which an uncontrolled addition of reactivity is caused by a rapid withdrawal of control rods from a suberitical or low power condition. 9002130072 900201 S ADOCK0500g9 g - DR r
. ) A positive MTC would yield the maximum peak heat flux. The accident analyses presented in Chapter 14 of the TMI-1 FSAR provided a sensitivjty study which examined the effects of-variations in the MTC from -0.6 x 10' to +1.0 x 10'4 delta k/k/'F. The resulting. peak thermal power and reactor coolant system peak pre;sure remained well below the acceptance criteria for this accident The staff concurs that the proposed increase in the NTC limit to +0.9 x 10'4 delta k/k/'F for power levels less than 95 percent of rated power has been. adequately considered And is bounded by the existing FSAR safety analyses. Above 95 percent of rated power the MTC is still required to be negative by Technical Specifications. A full power negativ MTC is specified such that the maximum clad temperatures will not exceed 2200 'F as specified in the i Final Acceptance Criteria based on loss of coolant accident (LOCA) analyses. A non-positive MTC at power levels above 95 percent of rated power is also required to prevent overpressurization of the reactor coolant system in the event of a feedwater line break. In addition, no adverso impact is exoected on the hydraulic and neutronic stability of TMI-1 due to the slightly larger positive MTC. The hydraulic and neutronic stability of TMI-1 is not expected to be different from the other B&W reattors at Crystal River 3. Oconee 1 2, and 3 Rancho Seco and Davis-Besse, which are already licensed for an MYC 34 limit of +0.9 x 10 delta k/k/'F from 0 to 95 percent full power. Therefore, the proposed change is acceptable. BWST Volume The BWST boric acid solution minimum volume of 40,000 gallons of 2270 ppm boron is sufficient to borate the reactor coolant system to a 1 percent subcritical margin in the cold condition at the worst time in core life with a stuck control rod assembly. This minimum volume includes the boron necessary to account for xenon decay as well as a 10 percent safety factor. The value of 40,000 gallons is provided in the Bases of Technical Specification Section 3.2 for information only and is not related to any existing technical specification requirement. Existing Technical Specification Section 3.3.1.1 bounds this value by specifying that the BWST 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, the proposed change is administrative in i nature and is acceptable. Maximum Tilt limit The proposed change to Technical Specification Section 3.S.2.4.f merely clarifies that the ' maximum" tilt-limit defined in the COLR shall be used to comply with this specification. This clarification was inadvertently omitted when the tilt limits were removed from the Technical Specifications and placed into the COLR. The proposed change merely provides additional clarification and is administrative in nature. Therefore, the staff finds the proposed change acceptable. LWR Limit One of the proposed changes to Technical Specification Figure 3.5-2M reflects an increase in the allowable LHR limit at the 2-foot core elevation from 14.0 i to 14.5 kw/ft for the burnup range between 0 to 1000 MWD /MTV. To support this proposed LHR increase, the licensee submitted the results of an ECCS analysis which was performed generically for the Babcock and Wilcox (B&W) lowered loop configuration plant with the Mark-B4 fuel rod design using the BAW-2 critical - +.
+ heatflux(CHF) correlation. The analysis was performed assuming a 50 psi reduction in fuel rod pre-pressure (fill gas pressure) for the most restrictive LOCA case. This is defined as the 8.55 ft8 double ended rupture atthereactorcoolantpumpdischargecold-leg)pipinglocationwiththepeak e power at the 2-foot core elevation (core inlet during beginning-of-life conditions. The results of the analysis, reported in BAW-2001P, indicate that the reduced internal fuel pin pressure allows for longer burnup periods (fuel cycles) and delays cladding rupture during a LOCA. An evaluation by the licensee-indicated that the 50 psi pin pre-pressure reduction would delay rupture by a time increment equal to a rise in the LHR of 0.5 kw/ft. The LOCA analysis, therefore, utilized an increased LHR of 14.5 kw/ft, as compared to the 14.0 kw/ft current generic LOCA limit, at the 2-foot core elevation for the burnup interval between 0 and 1000 MWD /MTU. The licensee used the current NRC-approved LOCA analysis computer codes for the analysis and the results were in conformance with the ECCS acceptance criteria of 10 CFR 50.46. The Mark-BZ fuel used in TMI-1 is not expected to affect the LOCA limits established for the Mark B-4 used in the analysis at the 2-foot elevation. In addition, the change in CHF correlation from the BAW-2 to the BWC correlation, used in the TMI-1 analyses, has no effect on the predicted time of DNB at the 2-foot elevation. Therefore, the proposed increase in allowable LHR from 14.0 to 14.5 kw/ft between 0 to 1000 MWD /MTU at the 2-foot elevation is acceptable. The licensee has also proposed a further change to Figure 3.5-2M which would increase the LHR limit af ter 1000 MWD /MTV from 15.0 to 15.5 kw/ft. This would l make the LHR limit for the 1000 to 2600 MWD /MTU burnup window identical to that for after 2600 MWD /MTU and eliminate the need for a 1000-2600 MWD /MTU window. The extrapolation of the ECCS analysis results to the next burnup window, allowing it to also be increased by 0.5 kw/ft, has been previously approved by the NRC in a letter from A. C. Thadani (USNRC) to C. N. Turk (B&W Owners Group Analysis Committee), dated October 12, 1987. Therefore, the proposed change to eliminate the 1000 to 2600 MWD /MTU burnup window and to relabel the "After 2600 MWD /MTU" window "Af ter 1000 MWD /MTU" is acceptable. Refueling Boron Concentration l l The staff does not accept the proposed removal of the specific refueling boron L concentration from the Bases of Technical Specification Section 3.8. All of I the current PWR Standard Technical Specifications contain a minimum required boron concentration during refueling to ensure that the reactor will remain suberitical by at least 5 percent delta k/k. Since the older TMI-1 Technical l Specifications do not contain this LCO, the boron concentration should remain l in the Bases for consistency both with the intent of the current Standard Technical Specifications and the initial conditions assumed for boron dilution events in the FSAR accident analyses. This value may, of course, change from the present value of 1800 ppm for longer cycle lengths.
SUMMARY
The staff has reviewed the proposeo TMl-1 Technical Specification changes submitted by letter dated October 4,1989 (Technical Specification Change Request No. 196) by GPU. Based on the above evaluation, these changes are found to be acceptable except for the proposed removal of the refueling boron concentration from the Bases of Technical Specification Section 3.8. The licensee letter dated December 22, 1989, also provided part of the basis for our approval. y
1 + 4 ENVIRONMENTAL CONSIDERATION The amendment changes a requirement with respect to installation or use of. a facility component located within the restricted areas as defined in 10 CFR Part 20. We have 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.off site, and that there is no sigt,1ficant increase in individual or cumulative occupational radiation exposure. The staff has previously issued 'a proposed finding that this the amendment involves no significant hazards consideration, and there has besn ne public connent on such finding. Accordingly, the amendment meets the eli categorical exclusion set forth in 10 CFR 51.22(c)gibility criteria for-(9). Pursuant to 10 CFR 51.22(b),noenvironmentalimpactstatementorenvironmentalassessmentneedbe . prepared in connection with the issuance of this amendment. CONCLUSION Wehaveconcluded,basedontheconsiderationsdiscussedabove,that(1)there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conductedincompliancewiththeCommission'sregulations,and(3)theissuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public. Principal Contributors: Lawrence Kopp Dated: February 1, 1990 a = _. _ _}}