ML20093M027
| ML20093M027 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/18/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20093M026 | List: |
| References | |
| NUDOCS 9510260165 | |
| Download: ML20093M027 (3) | |
Text
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t UNITED STATES g
NUCLEAR REGULATORY COMMIS810N WASHINoTON. D.C. 30006 4001 L
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i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENOMENT NO. 170 TO i
FACILITY OPERATING LICENSE N0. NPF-6 i
ENTERGY OPERATIONS. INC.
ARKANSAS NUCLEAR ONE. UNIT NO. 2 l
DOCKET NO. 50-368 i
11.0. INTRODUCTION i
17, 1995, Entergy Operations, Inc. (the licensee)
By letter dated March submitted proposed Technical Specification (TS) changes for the Arkansas Nuclear l
One, Unit 2 (ANO-2) plant. The proposed change deletes from the TS 4.5.2.g the i
requirement to verify the correct setting of the electrical and/or mechanical position stops for all eight High Pressure Safety Injection (HPSI) Emergency 1
Core Cooling System (ECCS) throttle valves. The proposed change does not affect the requirement to perform this verification for the Low Pressure Safety Injection (LPSI) ECCS throttle valves which is also specified in the same surveillance requirement.
2.0 BACKGROUND
i-2 The HPSI ECCS throttle valves are normally closed, motor-operated valves (MOVs)
. that have a safety function to open in order to allow flow of safety injection water into the reactor coolant system (RCS). As originally configured, the valves have electrical position stops (limit switches) which are set to obtain i
the required flow distribution for HPSI following a loss of coolant accident
'(LOCA). Due to the possibility of a change in the setting of the position stops s
from various causes, TS 4.5.2.g requires that they be verified at least once each 18 months.
During a refueling outage completed in April 1994, a modification identified as Design Change Package (DCP) 93-2012 was installed. This DCP included the addition of manual valves upstream of four of the eight MOVs to provide the flow throttling function previously accomplished by the MOVs. A similar modification will be: installed in the other four HPSI lines during the next refueling outage r
scheduled to begin in September 1995.
p Enclosure.
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-9510260165 951018
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.O t' l 3.0 EVALUATION NUREG-1432, restructured " Standard Technical Specification'- Combustion Engineering Plants," contains surveillance requirements (SR) 3.5.2.9 which is equivalent to ANO-2 TS 4.5.2.g.
It is marked as a specification requiring plant-specific input. The basis;for SR 3.5.2.9 states, "This SR is not required for units with flow limiting orifices." Since manual throttle valves fixed into position function as flow limiting orifices, the proposed change is consistent with the corresponding requirement in NUREG-1432.
Following completion of the modification in which manual valves are adi.d upstream of each of the eight MOVs, verification of the correct position stop settings for the HPSI MOVs will not be necessary. This is because the valves
- will then actuate to the fully open position. Actuation to the fully open
. position will be verified as part of the ASME Section XI testing program. HPSI
. flow will be controlled by manual valves that will be fixed in position by tack I
welding a valve handle restraint to the valve yoke following satisfactory verification of flow balancing. Flow balancing assures adequate flow to the Reactor Coolant System (RCS) in the event of LOCA. The proposed modified j
configuration is similar to the existing configuration of ANO Unit 1.
i The licensee's use of the new manual valves will perform the throttling function previously performed by the HPSI. isolation MOVs, without reliance upon any 1
electrical equipment (MOV limit switches). The throttling function to be performed by the manual valves will be more reliably performed by passive components than by active electrical circuits. The change eliminates uncertainty in throttle valve position as a result of limit switch tolerances 1
4 and repeatability, which form the basis for the current SR for periodic verification.
- The staff has found that the modification which eliminates the SR for the HPSI j
i ECCS MOVs to be acceptable as the proposed change to remove the requirement to verify the correct settings of position stops for the HPSI throttle valves is consistent with NUREG-1432. This is because the manual throttle valves fixed i.
into position serve the function of, and are equivalent to flow limiting orifices. Also, the.new manual valves are less likely to fail in operation 4
3 since they are fixed into position by tack-welding locking devices and therefore, perform their function passively.
Inadvertent manipulation of the
. manual valves will be prevented by the locking arrangement.
In addition, this nodification is similar to the existing configuration of ANO Unit 1.
4.0 TECHNICAL CONCLUSION 4
Based on the staff's evaluation in Section 3.0 above, the staff concludes that the licensee's proposed revisions to the HPSI system throttle valve surveillance in TS 4.5.2.g are acceptable.
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. 4 5.0. STATE CONSULTATION 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 comments.
- 5.0 ENVIROOMENTAL CONSIDERATION
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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 and changes surveillance requirements. 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
_l radiation exposure. The Comission has previously issued a proposed finding that the amendment involves no-significant hazards consideration, and there has been no public coment on such finding (60 FR 37089). Accordingly,-the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR SI.22(b) no environmental impact statement or. environmental assessment need be prepared in connection with the issuance of the amendment.
7.0 IQELUSION l
The Comission 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 activities will be conducted in compliance with the Comission's regulations, 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: H. Balukjian j
Date: ' October 18, 1995
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