ML20088A837
| ML20088A837 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/27/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20088A835 | List: |
| References | |
| NUDOCS 8404130192 | |
| Download: ML20088A837 (3) | |
Text
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o UNITED STATES
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NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555
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SAFETY EVALUATI0fl BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 72 TO FACILITY OPEPATIflG LICENSE NO. DPR-69 RALT!MORE GAS AND ELECTRIC COMPANY CALVERT CLIFFS fiUCLEAR POWER PLANT UNIT ?!0. 2 DOCKET NO. 50-318 Introduction By application for license amendment dated December 22, 1983 Baltimore Gas and Electric Company (BG&E) requested changes to the Technical Specifications (TS) for Calvert Cliffs Unit 2.
The application was supplemented by two letters dated January 27, 1984. The proposed amendment would change the TS to reflect revised linits on shutdown margin and moderator temperature co-efficient to accommodate a new steam line break analysis.
Discussion and Evaluation The proposed changes to the TS provide for:
(1) revised shutdown margin limits, decreased from greater than or equal to 5.2% delta k/k to greater than or equal to 4.3% delta k/k per TS 2/4.1.1, " Shutdown Margin - T greater than 200 F", gnd (2) a change to the ryerator temperature coefMient (MTC) fron -2,2x10- delta k/k/"F to -2.5x10~ delta k/k/ F per TS 3/4.1.1.4,
" Moderator Temperature Coefficient." The proposed TS changes for shutdown margin and MTC result from the introduction of a revised main stean line break (MSLB) analysis for Unit 2.
The analysis was previously referenced for Unit 1 for Cycle 7 operation and was intended to be eventually submitted for Unit 2.
In 48 FR 46665, the Commission proposed that Unit 1, Cycle 7 TS changes, including those resulting from the revised MSLB,-involve no significant hazards consideration. The TS changes for Unit 1 Cycle 7 operation, including changes to the fiTC and shutdown margin which are the same as presently pro-posed for Unit 2, were issued as Unit 1 Mendment 88 on November 17, 1983.
The steamline break (SLB) analysis is performed using conservatively envelopine initial. conditions and assumptions such that the results will be applicable to a large number of future plant operating cycles. The effect of the safety
. grade Auxiliary Feed Actuation System (AFAS) is incorporated in the analysis.
The analysis includes a spectrun of steamline break sizes both inside and outside the containment initiated from hot full power and hot zero power.
The licensee has detennined that the steamline break events initiated from the hot full power conditions are the most limiting and the analysis results in HFP steanline breaks are provided.
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8404130192 940327 PDR ADOCK 05000318 P
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. For the inside containment steanline break event, the licensee's parametric study has determined that the largest-size steanline break from the hot full power condition with loss of AC power on turbine trip results in the naximum post trip return-to-power and minimum post trip transient DNBR. The inside containment SLB event is analyzed using the assumptions having the greatest positive reactivity insertion, i.e., (1) the noderator temperature coefficient and the fuel Doppler coefficient are the values corresponding to the end of life values; (2) the moderator density reactivity change is a function of moderator density calculated with the highest worth CEA stuck in the fully withdrawn position; (3) the Doppler multiplier and the delayed neutron frac-tion are the maximum absolute values for the end of life conditions; (4) the boron reactivity is a conservatively low value for safety injection flow from the safety injection pumps; and (5) the CEA worth available for shutdown is the minimum value.
The analysis results for the 6.305 ft2 SLB with loss of AC power on turbine trip initiated from HFP, shown in Table 7.3.2-4 of the submittal, indicates a peak return-to-power of 8.1%.
Using the approved MacBeth critical heat flux correlation, the result shows that the DNBR limit of 1.30 is not violated during this limiting SLB event.
For the outside containment SLB, the analysis is performed with the initial conditions and assumptions which maximize the power excursion prior to reactor trip. The licensee has determined that a 0.65 ft2 SLB outside containment with loss of AC power on turbine trip initiated from HFP results in the maximum power excursion and site boundary dose release.
In general, the analysis is perforned with assumptions of minimum negative reactivity inser-tion, i.e., (1) the Doppler coefficient is based on the beginning of life fuel temperature coefficient; (2) the Doppler multiplier is a conservatively low value.to minimize Doppler feedback; (3) the delayed neutron fraction is the minimum value from the end of life; and (4) a range of moderator tempera-ture coefficients is used to determine its effect on power range detector response during the SLB event. The results show that less than 1% of the fuel pins experience DNB. The licensee assumes a 2% fuel failure for the site boundary dose calculation and the result shows thyroid dose of 81 rem and the whole body dose of 0.3 rem, within the guidelines of.10 CFR 100.
The proposed changes to TS 3/4.1.1.1 and 3/4.1.1.4 are consistent with the assumptions made in the MSLB analysis and assure that the MSLB analysis remains valid for operation of Calvert Cliffs Unit 2.
Accordingly, we find the proposed changes to TS 3/4.1.1.1 and 3/4.1.1.4 to be acceptable.
Environmental Consideration We have determined that the amendment does not authorize a chance in effluent types or total amounts nor an increase in power level and will not result-
'in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is in-sianificant from the standpoint of environmental impact and, pursuant to
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10 CFR 651.5(d)(4), that an environmental impact statement or negative declar.ition ar;d environmental impact appraisal need not be prepared in connection with the issuance of the amendment.
Conclusion We have concluded, based on the considerations discussed atove, that:
(1) 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 compliance with the Comiss%n's regulations and the issuance of the amendment will not be inimical to tne common defense and security or to the health and safety of the public.
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Date: March 27, 1984
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Principal Contributor:
D. Jaffe 1 J 7
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