ML20216A874
| ML20216A874 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/23/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20216A872 | List: |
| References | |
| NUDOCS 8706260401 | |
| Download: ML20216A874 (3) | |
Text
f a ncy'o, UNITED STATES
[
g NUCLEAR REGULATORY COMMISSION
]
y,
- j WASHINGTON, D. C. 20555
]
k... + p#
. SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 1 TO FACILITY OPERATING LICENSE NPF-68 3
i GEORGIA POWER COMPANY, ET AL l
DOCKET NO. 50-424
]
V0GTLE ELECTRIC GENERATING PLANT, UNIT 1 i
I.
INTRODUCTION
]
By letter dated March 30, 1987 Georgia Power Company, et al., (the licensee) re-quested a change to the Technical Specifications for Vogtle Electric Generating Plant, Unit 1.
The th,ange proposed would increase-the shutdown margin require-ments shown in Figure 3.1-2 and change the title of Figure 3.1-2.
The proposed Figure 3.1-2 shows the required shutdown margin for Mode 4 when no reactor
)
coolant pumps are in operation and for Mode 5 at all times. The boron dilution j
accident analysis is the basis for this curve. Westinghouse has recently re-vised its analysis methodology for analyzing boron dilution accidents, and the proposed chenge is a result of this reanalysis. The proposed title change would J
avoid confusion with Technical Specification Figure 3.1-1 and be consistent with Technical Specification 3.4.1.3.
II. EVALUATION Because of its review of the Diablo Canyon natural circulation test results, the NRC staff concluded that under low flow, natural circulation conditions, the water in the reactor vessel upper head could become stagnant and not actively mix with the remainder of the reactor coolant. Dissolved boron in-the water within the upper head would not be available to mitigate the con-sequences of a boron dilution accident.
The licensee took credit for the boron contained in the water within the reactor vessel upper head when the Final Safety Analysis Report boron dilution accident analysis was performed.
Due to the revised NRC staff position. Westinghouse reanalyzed the Vogtle boron dilution accident for Modes 4 and 5 when no reactor coolant pumps are in operation.
In the new analyses, no credit was taken for the boron in the water within the reactor vessel upper head.
Fcr dilution events during hot standby, hot shutdown and cold shutdown (Modes 3, 4, and 5), Technical Specification 3.1.1.2 specifies the required shutdown margin as a function of RCS boron concentration. The specified shutdown margin ensures a minimum of 15 minutes from the time of the high flux at shutdown alarm to the total loss of shutdown margin. A reduction in the' active mixing volume results in a reduction in time available for operator action. However, an increased boron requirement can be used to offset this reduction in time.
87062604O2 870623 gDR ADOCK 05000424 PDR
. The boron dilution event for Vogtle was reanalyzed to exclude the water within the reactor vessel upper head, and the result was that a slightly higher boron concentration was needed to ensure the required 15 minute time requirement.
The proposed Technical Specification Figure 3.1-2 reflects this slightly in-creased boron requirement. The Westinghouse reanalysis was perfortned with staff approved models.
The staff finds that the requested changes are acceptable because:
(1)they are based upon analyses performed with approved methods and (2) the 15 minute time requirement will be satisfied with the proposed higher boron concentration.
Further, the title change of Figure 3.1-2 is acceptable because it removes the,
overlap regarding pump operation which currently exists between Figures'3.1-1 and 3.1-2.
III. ENVIRONMENTAL CONSIDERATION
~
This amendment invoNes.a change in the use of facility components located within the restricted area as defined irr 10 CFR Part 20. The staff has deter-mined 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 significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a pro-posed finding that the amendment involves no significant hazards consideration, 3
and there have been no public comments on such finding. 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 i
statement or environmental assessment.need be prepared in connection with the issuance of this amendment.
IV. CONCLUSION The Commission made a proposed determination that the amendment involves no l
significant hazards consideration which was published i'n the Federal Register (52 FR 18981) on May 20, 1987, and consulted with the state of Georgia.
No public coments were received and the state of Georgia did not have any coments.
The staff 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, and (2) such activities will' be conducted in compliance with the Comission's rt:9u1ations, and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Velanie Miller, DRPI/II/PDII-3 Margaret Chatterton, DEST /SRXB Dated:
June 23, 1987
June 23, 1987
.~
AMENDMENT N0. 1 TO FACILITY OPERATING LICENSE NPF V0GTLE ELECTRIC GENERATING PLANT, UNIT 1 DISTRIBUTION: w/ enclosures:
Q)ocket Nos3 '50-424 NK vun Local PDR PRC System PDII-3 Reading B. J. Youngblood l
M. Miller M. Duncan OGC-Bethesda T. ' Barnhart (8)
E. L. Jordan J. Partlow ACRS (10)
E. Butcher W. Jones ARM /LFMB L. Reyes M. Chatterton i
S. Varga G. Lainas D. Hagan GPA/PA l
,