ML20129E766
| ML20129E766 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/27/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20129E762 | List: |
| References | |
| NUDOCS 9610030282 | |
| Download: ML20129E766 (4) | |
Text
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j NUCLEAR RtiGULATORY COMMISSION 2
WASHINGTON, D.C. 20666 4 001 o\\
f osse SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.121TO FACILITY OPERATING LICENSE NO. NPF-38 ENTERGY OPERATIONS. INC.
i WATERFORD STEAM ELECTRIC STATION. UNIT 3 DOCKET NO. 50-382 l
1.0 INTRODUCTION
By application dated November 7,1995, as supplemented by letter dated April 11, 1996, Entergy Operations, Inc. (the licensee), submitted a request for changes to the Waterford Steam Electric Station, Unit 3 (Waterford 3),
i Technical Specifications (TSs). The requested changes would modify the TSs related to Safety Injection Tanks (SIT) level and pressure setpoints. The April 11, 1996, letter provided clarifying information that did not change the l
initial proposed no significant hazards consideration determination or expand the scope of the original Federal Reaister notice.
2.0 EVALUATION l
There are four SITS in the Emergency Core Cooling System (ECCS) at Waterford 3.
These SITS are designed to provide borated water to the reactor vessel (RV) during the blowdown and refill phase following a large Break Loss of Coolant Accident (LBLOCA). During plant operation, the SITS are partially filled with borated water and pressurized with nitrogen gas. Appropriate pressure and water level are maintained in the SITS during plant operation to assure that tank water will be injected into the RV following a LBLOCA at a rate and volume consistent with safety analysis.
The current TS 3/4.5.1 requires that SITS be operable with a water volume in the range of 1679 cubic feet (78%) to 1807 cubic feet (83.8%) and a nitrogen pressure between 600 psig to 625 psig. The proposed changes to TS 3/4.5.1 would require that the SITS be operable with a water volume in the range of 926 cubic feet (40%) to 1807 cubic feet (83.8%) and a nitrogen pressure between 600 psig to 670 psig. These changes would reduce the excessive cycling of Safety Injection System components for frequent refill of the SITS due to system leakage.
The licensee has provided the results of an analysis to support its proposed TS changes. The supporting analysis was performed in two steps:
9610030282 960927 PDR ADOCK 050003G2 P
. 1)
The first step was a parametric study of SIT level and pressure, i
over the expanded ranges, to determine the limiting SIT conditions for use in the LBLOCA analysis. The results of the study determined that for the range of level (40 percent to 83.8 percent indicated) and pressure (600 to 670 psig indicated) that was investigated, the maximum level and minimum pressure are the limiting SIT conditions for the LBLOCA analysis which would result in the worst consequences following a LBLOCA. Small break LOCA evaluation was also performed i
to justify the proposed changes regarding SIT conditions.
It is concludedthatthechangesareacceptablebecausethelimitingsmall i
break LOCA, the 0.04 ft, discharge leg break, does got credit injection from SITS. For breaks larger than 0.04 ft, increasing j
SIT pressure and decreasing SIT level results in an increased SIT
~
j flow rate and, therefore, would improve the transient results.
2)
The second step was to reanalyze the LBLOCA using Asea Brown Boveri i
Combustion Engineering's NRC approved ECCS performance evaluation model documented in CENPD-132, Supplement 3-P-A, " Calculational s
Methods for the CE Large Break LOCA Evaluation Model for the Analysis of CE and Westinghouse Designed NSSS", June 1985, with the t
limiting SIT conditions identified in step 1 above. The results of i
the reanalysis demonstrated conformance to the ECCS acceptance criteria of 10 CFR 50.46, and there is a high-level of probability i
that the criteria will not be exceeded.
The acceptance criteria of 10 CFR 50.46 are outlined below:
1.
The calculated maximum fuel element cladding temperature shall not exceed 2200'F.
2.
The calculated total oxidation of the cladding shall nowhere exceed 0.17 times the total cladding thickness before oxidation.
3.
The calculated total amount of hydrogen generated from the chemical i
reaction of the cladding with water or steam shall not exceed 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding cylinders surrounding the fuel, excluding the cladding surrounding the plenum volume, were to react.
4.
Calculated changes in core geometry shall be such that the core remains amenable to cooling.
5.
After any calculated successful initial operation of the ECCS, the calculated core temperature shall be maintained at an acceptably low value and decay heat shall be removed for the extended period of time required by the long-lived radioactivity remaining in the core.
The licensee determined that the proposed changes are also acceptable for a Small Break Loss of Coolant Accident (SBLOCA) since the analysis of the limiting SBLOCA does not credit water injection from SITS following the event.
l The staff agrees with this licensee's conclusion.
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1 The licensee's proposed changes in TS 3/4.5.1 reflect the changes discussed above. The staff has reviewed the licensee's assessment presented in its submittal and finds' that the changes are reasonably conservative and are acceptable.
I l
The bases of the staff's acceptance are as follows:
1)
The licensee has identified the most limiting conditions associated with the water level and pressure of the SITS using parametric study. The postulated LBLOCA has been reanalyzed assuming the most limiting water level and pressure identified above. The results of the licensee's reanalysis confirms that the ECCS acceptance criteria of 10 CFR 50.46 are met. The staff agrees with the licensee's assessment.
2)
The proposed TS limits of the SIT water level and pressure would result in less severe consequences following a LBLOCA. Therefore, they are conservative and acceptable.
3)
The-license used the approach specified above which is consistent with the requirements of 10 CFR 50.46 to support its ECCS modifications.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State official was notified of the preposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has 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 offsite, and that there is no significant increase in individual or cumulative occupational radiation 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 (60 FR 58401). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 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 the amendment.
5.0 CONCLUSION
The' Commission has concluded, based on the considerations discussed above,
.that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such
. <i activities will be conducted in compliance with the Comission's regulations, i
and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
C. Y. Liang Date: September 27, 1996