ML20199F793
| ML20199F793 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 01/19/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20199F790 | List: |
| References | |
| NUDOCS 9901220061 | |
| Download: ML20199F793 (4) | |
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51 UNITED STATES a
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,j NUCLEAR REGULATORY COMMISSION o
f WASHINGTON, D.C. 30666 0001
+9.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO 199 TO FACILITY OPERATING LICENSE NO. NPF-6 ENTERGY OPERATIONS. INC.
ARKANSAS NUCLEAR ONE. UNIT NO. 2 DOCKET NO. 50-368
1.0 INTRODUCTION
By letter dated June 29,1998 (2CAN069806), Entergy Operations, Inc. (the licensee) submitted a request for changes to the Arkansas Nuclear One, Unit 2 (ANO-2), Technical Specifications (TSs). The requested changes would revise the Applicability of TS 3.4.2, " Reactor Coolant System - Safety Valves - Shutdown." An associated action would also be revised and a footnote would be removed. The amendment would also revise TS 3.4.12, " Reactor Coolant System -
Overpressure Protection," allowing safety injection tanks (SITS) to remain unisolated if they are pressurized to less than 300 psig and making some editorial changes. In addition, affected index and Bases pages would be revised.
Because the amendment is being issued very close to the beginning of the refueling outage, the licensee verbally requested a change to the effective date of the amendment on December 17, 1998. The licensee requested that the effective date be within 60 days after the amendment is issued. The staff finds this change acceptable.
2.0 EVALUATION This evaluation will be performed in three parts: (1) changes related to the applicability for the safety valves (shutdown), (2) changes related to the isolation of the SITS, and (3) human factors and administrative changes.
2.1 Chances Related to the Acolicability For the Safety Valves (Shutdown)
Current TS 3.4.2 is applicable in Modes 4 and 5. However, these modes overlap, in part, with the applicability for TS 3.4.12 for the low-temperature overpressure protection (LTOP) system which is required in Mode 4 with cold leg temperature (I) less than or equal to 220*F, Mode 5, and Mode 6 with reactor vessel head in place. The licensee proposed to revise the applicability for TS 3.4.2 to Mode 4 with T, greater than 220*F.
The design basis pressurization event in the modes in which the LTOP system is required is a simultar,eous injection by two high pressure safety injection pumps and all three charging pumps to & water-solid reactor coolant system (RCS). The LTOP system is designed with adequate 9901220061 990119 DR ADOCK 05000368 PDR
c capacity to protect the RCS during this event. Therefore, the pressurizer code safety valves are not required in these modes. The staff concludes that this change is acceptable.
The current Action Statement in TS 3.4.2 states:
With no pressurizer code safety valve OPERABLE, immediately suspend all operations involving positive reactivity changes and place an OPERABLE shutdown cooling loop into operation.
The licensee proposed the following revised Action Statement:
With no pressurizer code safety valve OPERABLE, reduce T, to s 220*F within i
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The revised action involves changing the plant status so that TS 3.4.2 is no longer applicable i
and the LTOP is required to be in service to protect the RCS from overpressurization. The change deletes the requirement to immediately suspend all operations involving positive reactivity changes. The licensee indicated that reducing the RCS temperature is an operation that adds positive reactivity. Therefore, the current requirement would conflict with the action to exit the mode in which the safety valves are required. In addition, the licensee indicated that control of the shutdown margin is still required by TS 3.1.1.1.
The change to the Action Statement also deletes the requirement to place an operable shutdown cooling loop into operation. The licensee indicated that a shutdown cooling loop does not have adequate relief capacity to ensure RCS overpressure protection. With no pressurizer code safety valves operable, the proposed action requires the licensee to achieve the plant conditions necessary to place the LTOP system in service, thus providing overpressure protection.
The last aspect of the change to the Action Statement is the addition of a 12-hour completion time. The current Action Statement does not include a specific completion time for placing the shutdown cooling loop into operation. The licensee indicated that the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> allowance to reduce RCS temperature to bring the unit to less than or equal to 220*F is reasonable without challenging plant systems. The RCS contains lower energy levels (reduced pressures and temperatures) in Mode 4, which reduces the potential for large pressurizer insurges which would challenge the overpressure protection systems. The licensee also indicated that the 12-hour completion time is consistent with the improved standard TS for Combustion Engineering plants.
The staff has reviewed TS 3.4.3,
- Reactor Coolant System Safety Valves - Operating," in conjunction with the proposed changes to TSs 3.4.2, " Reactor Coolant System Safety Valves -
Shutdown," and 3.4.12, " Reactor Coolant System Overpressure Protection," and verified that adequate overpressure protection for the RCS would be provided for the complete range of operations. In addition, the staff has concluded that the appropriate and conservative response to a plant condition in which the RCS was operating in Mode 4 with I greater than 220'F and no pressurizer code safeties operable would be to reduce RCS T, to less than or equal to 220 F such that the LTOP relief valves could provide overpressure protection for the RCS. Therefore, the staff concludes that the removal of Action Statement references to restrict the addition of
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3-e positive reactivity and requiring the initiation of shutdown cooling are acceptable. The addition of a 12-hour time limit to reduce T, to less than or equal to 220'F is commensurate with the safety significance of the condition and consistent with similar situations already addressed in the Technical Specifications ( e.g., TS 3.4.3). Therefore, the staff concludes that the changes to l
the Action Statement are acceptable.
Finally, the current TS 3.4.2 includes a "#" footnote related to Mode 5. Since this TS would no j
longer be applicable in Mode 5, the licensee proposed to delete the footnote. The staff has i
reviewed this change and concludes that it is acceptable.
The licensee also revised the associated Bases to reflect these changes. The staff reviewed the changes and finds that they are acceptable.
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2.2 Chanoes Related to the isolation of the SITS l
Current TS 3.4.12 requires each SIT to be isolated if its pressure is greater than or equal to RCS l'
pressure. The licensee proposed to revise the TS to require isolation of a SIT if its pressure is greater than or equal to 300 psig. This change is intended to allow flow testing of the SIT l
discharge check valves with the plant shut down. The revised pressure limit is added to the limiting condition for operation (LCO) and to Actions d. and d.1 and the current "" footnote is removed.
The licensee indicated that the 300 psig limit was established in order to minimize the chances of an inadvertent isolation of the shutdown cooling system during the check valve test. The licensee indicated that the check valve test would typically be performed in Mode 5 and that the 300 psig limit was well below the LTOP lift set point (less than or equal to 430 psig). The i
300 psig limit does not consider instrument inaccuracies. However, because the limit is 130 psi below the maximum LTOP relief valve set point, there is clearly margin available that exceeds the instrument inaccuracies. This conclusion is supported by a comparison of the minimum SIT 4
pressure during operations (600 psig in TS 3.5.1) and the SIT pressure used in the loss-of-coolant accident analyses (550 psia in Final Safety Analysis Report Tables 6.3-9 and 6.3-17).
The staff has concluded that the proposed limit allowing the SITS to be unisolated with SIT pressure less than or equal to 300 psig is acceptable as this pressure limit is significantly below the LTOP relief valve setpoint of 430 psig and would not challenge the overpressure protection provided for the RCS in this condition. Therefore, the staff concludes that the change is acceptable.
The licensee also revised the associated Bases to reflect these changes. The staff reviewed the changes and finds that they are acceptable.
2.3 Human Factors and Administrative Chanoes The licensee proposed to revise the title of LCO 3.4.12, make associated changes to the LCO statement, and add the LCO to the TS indexes. These changes are administrative and are acceptable. The licensee also proposed changes to Actions b., d., d.1 and d.2 to clarify l
completion times. The staff finds that the revised statements are equivalent or more restrictive l
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.' to the current statements and are, therefore, acceptable. Finally, current Action d.2 requires the licensee to increase cold leg temperature to greater than or equal to 220*F. However, at exactly 220*F the LCO would still be applicable. The licensee proposed to change the action to require increasing cold leg temperature to greater than 220*F, exiting the applicability for the LCO.
While the staff recognizes that it is physically impossible to maintain the plant at exactly 220'F, this change corrects a deficiency in the current TS and is acceptable.
3.0 STATE CONSULTATION
l In accordance with the Commission's regulations, the Arkansas State official was notified of the proposed issuance of the amendment. The State official had no comment.
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4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change i
surveillance requirements. The NRC staff has determined that the amendments involve 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 l
occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding (63 FR 56243). Accordingly, the amendments meet the eligibility I
criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) l no environmental impact statement or environmental assessment need be prepared in L
connection with the issuance of the amendments.
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 l
operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Andrew Kugler l
Date:
January 19, 1999 i
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