ML20134P380
| ML20134P380 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/19/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20134P379 | List: |
| References | |
| NUDOCS 9702250406 | |
| Download: ML20134P380 (5) | |
Text
N u r 141..
g NUCLEAR REGULATORY COMMISSION WASNINGToN. D.C. asse64est
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION j
an ATED TO Aprun4ENT No.133 s
j TO FACILITY OPERATING LICENSE No. NPF-49 e
j MDRTHEAST W CLEAR N ecY t m 8ANY. ET AL.
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_ MILLETGNE NUCLEAR Pnure STATION. laitT MD. 3,,,
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DDCKET ND. 50-423 l
1.0 INTRODUCTION
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j By [[letter::05000336/LER-1991-009, :on 910821,both EDGs Declared Inoperable.Caused by Load Swings Due to Oxidation Buildup on Relay Contacts. Governor Controls Sys on 12U DG & 13U DG Updated W/New Electronic Governor Actuator Controls|letter dated July 18, 1995]], the Northeast Nuclear Energy Company, et al.
(NNECO), submitted a request for changes to the Millstone Nuclear Power i
Station, Unit No. 3 Technical Specifications (TS). The requested changes would revise the TS to extend the surveillance schedule from 18 months to each i
refueling interval (nominally 24 months) for TS 3/4.4.4, " Relief Valves;" TS 1
3/4.4.6.1, " Reactor Coolant System Leakage;" TS 3/4.4.6.2, " Operational I
Leakage;" TS 3/4.4.g.3, " Overpressure Protection Systems;" and TS 3/4.4.11, j
" Reactor Coolant System Vents." This amendment involves only a portion of the surveillance requirements affected by a change to a 24-month operating cycle between refuelings. The remaining changes are the subject of other amendment j
requests.
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2.0 BACKGROUND
Generic Letter (GL) gl-04 dated April 2, 1991, was issued by the NRC to i
provide guidance to licensees for proposing changes to TS requirements for 4
i surveillance intervals to accommodate a 24-month refueling cycle. Because of the significant economic benefits associated with a longer fuel cycle, many licensees are using improved reactor fuels to extend the operating cycle
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between refuelings. Since the existing TS were based on an 18-month cycle, the frequency of performing surveillances that might require plant shutdown was specified at 18 months plus 25 percent or a maximum interval of 22.5 months.
Licensees were advised to evaluate the results of the performance of the surveillance tests previously perfonned at the 18-month interval as well as maintenance records and other perfonaance data, to justify any requested extension of the testing interval-to 24 months plus 25 percent or a maximum interval of 30 months.
In addition, GL 91-04 allows deletion of the _
j requirements in some of the TS that the surveillance be performed during j
shutdown.
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3.0 EVALMTIM i
Section 50.36(c)(3) of Title 10 of the Code of Federal Raoulations (10 CFR) requires TS to include surveillance requirements related to test, calibration, or inspection to assure that the necessary qualification of systems and components is maintained, that operation will be w4 thin safety limits, and that the limiting conditions for operation will be met. The intent of 18-month surveil.ance intervals is to meet this requirement. The staff, after reviewing a number of licensee requests to extend 18-month surveillance 4
intervals to 24-month intervals, because of longer fuel cycles, found that the effect on safety of such changes was small. Consequently, on April 2, 1991, i
the staff issued GL 91-04 that described necessary support licensees must l
provide for proposed changes to TS surveillance requirements in order to j
accommodate a 24-month surveillance interval while still meeting the requirements of 10 CFR 50.36(c)(3).
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The design, fuaction, and operation of the components and systems involved in this amendment request are unchanged. They are as described in the Final l
Safety Evaluation Report and in the application for amendment dated July 18, i
1995. The only cons % ration needed for each of these extensions in testing j
interval is an assessment of the history of the performance of these J
components and systems as demonstrated by the results of previous surveillance j
tests, corrective and preventative maintenance, and other operation.
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l 3.1 TS 4.4.4.1.a and 4.4.9.3.1.b - Power Operated Relief Valve (PORV) High i
Pressure Logic and PORV Actuation Channel Calibration l
l TS 4.4.4.1.a verifies the operability of the PORVs (high pressure logic) by performance of a channel calibration. TS 4.4.9.3.1.b verifies the operability of the.PORVs (Iow temperature operation) by a performance of a channel j
calibration.
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The licensee performed a review of the components tested by TS 4.4.4.1.a and 4.4.9.3.1.b over the last four operating cycles to determine the impact of extending the frequency to each refueling interval. This review included surveillance results, preventative maintenance records, and the frequency and i
type of the corrective maintenance. The licensee's review determined that l
channels were calibrated within the acceptance criteria and there was no i
indication of linear time dependent drift with regard to the circuit i
components. -There are no regularly scheduled maintenance and/or calibration i
activities associated with these parameters of the PORV.high pressure or i
actuation logic. The licensee's review of corrective maintenance activities i
did not identify any significant activities *4 hat were required to correct component failures.
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Based on the above, the staff finds that the extension of the testing time i
interval from 18 months to,each refueling interval for TS 4,4.4.1.a and j
4.4.9.3.1.b is acceptable.
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- i 3.2 TS 4.4.4.1.b, 4.4.4.3, and 4.4.11.3 - PORV and Reactor Coolant System i
(RCS) Vents TS 4.4.4.1.b verifles the operability of each PORV by operating the valve through one complete cycle of full travel during Modes 3 or 4.
verif' es the operability of the emergency power supply for the PORVs and block i
valves by operating the valves through a complete cycle of full travel. TS l
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, 4.4.11.3 requires that each train of the pressurizer steam space vent path be demonstrated operable per applicable requirement of TS 4.4.4.1 through 4.4.4.3 i
and 4.4.9.3.1.
In addition, flow is verified through the pressurizer steam space vent path during venting.
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The licensee performed a review of the components tested by TS 4.4.4.1.b, 4.4.4.3, and 4.4.11.3 over the last four operating cycles to determine the i
impact of extending the frequency to each refueling interval. This review l
included surveillance results, preventative maintenance records, and the l
frequency and type of the corrective maintenance. The licensee's review 1
determined that there was one case of not meeting the stroke time acceptance i
criteria during 1986. The licensee's investigation determined the slow stroke
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time was caused by the orifice in the solenoid valves that vent the PORVs to j
open them. A design change was implemented to remove the orifices and the i
stroke times were found normal. All subsequent tests from 1986 to the date of i
the submittal met the acceptance criteria. The licensee's review found that l
PORV maintenance problems have occurred with the indication circuits and have been traced to a weakening of the magnet that operates the position switch.
This does not affect the valve operability since a temperature rise or 4
pressure drop provides a proof for the correct operation of the valve. The i
licensee's review also determined that there have been no failures of the PORVs or the block valves to operate.
In addition, TS 4.4.4.2 provides.
additional assurance that the block valves are operable.
Based on the above, the staff finds that the extension of the testing time interval from 18 months to each refueling interval for TS 4.4.4.1.b, 4.4.4.3, and 4.4.11.3 is acceptable.
3.3 TS 4.4.6.1.b - Containment Drain Sump Level and Pump Capacity Monitoring System Channel Calibration TS 4.4.6.1.b requires that the containment drain sump level and pumped capacity monitoring system instrumentation be calibrated.
s The licensee performed a review of the components testad by TS 4.4.6.1.b' over the last surveillances to determine the impMt of extending the frequency to each refueling interval. This review included surveillance results, preventative maintenance records, and the frequency and type of the.serrective maintenance. The licensee's review determined that these instruments teere calibrated within the acceptance criteria and there was no indication of linear time' dependent drift with regard to the circuit components. The licensee's review also determined that past preventative maintenance and corrective maintenance activities did not identify any significant activities that were required to correct component failures.
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4-Based on the above, the staff finds that the extension of the testing time interval from 18 months to each refueling interval for TS 4.4.6.1.b is acceptable.
3.4 TS 4.4.6.2.2.a - RCS pressure Boundary Isolation Valves TS 4.4.6.2.2.a verifies operability of the RCS pressure boundary isolation valves by verifying leakage to be within the limit.
ThelicenseehrformedareviewofthecomponentstestedbyTS4.4.6.2.2.a over the last operating cycle to detamine the impact of extending the frequency to each refueling interval. This review included surveillance results, preventative maintenance records, and the frequency and type of the corrective maintenance. The licensee's review determined that reliability of the RCS isolation valves is high. The four failures were due to the valve not seating properly at low RCS pressure and accumulation of crud between the valve clapper and the valve seat. When the valves were ratested at higher pressure or after flushing, the valves passed. The licensee's review determined that the majority of corrective maintenance was performed on the four motor-operated valves (MOVs) due to their inherent complexity compared to the check valves. The corrective maintenance involved packing leakage and position indication adjustments. The licensee's review determined that the only preventative maintenance that is scheduled on an 18-month frequency for the MOVs involved visual inspection of the overall valve condition.
In addition, the RCS leakage is continuously monitored by verifying RCS inventory at least once every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Based on the above, the staff finds that the extension of the testing time interval from 18 months to each refueling interval for TS 4.4.6.2.2.a is acceptable.
3.5 TS 4.4.11.2.a. b, and c - Reactor Vessel Head Vent Path Valves TS 4.4.11.2.a, b, and c verify operability of the reactor vessel head vent flow path by verifying that all manual isolation valves in the vent path are locked in the open position, by cycling each vent valve through at least one complete cycle of full travel from the control room, and by verifying flow through the RCS vent paths during venting.
The licensee perfomed a review of the components tested by TS 4.4.ll.2.a. b, and c over the last four operating cycles to determine the impact of extending the frequency to each refueling interval..This review included surveillance results, preventative maintenance records, and the frequency and type of the corrective maintenance. The licensee's review determined that the surveillances. performed to verify proper valve position and valve cycling were all acceptable. The licensee's review determined that corrective maintenance performed on the valves involved position indication problems, which did not indicate any generic valve operability problems. The licensee's review also determined that there are no periodic maintenance for the reactor vessel head vent path valves scheduled on an 18-month frequency.
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. Based on the above, the staff finds that the extension of the testing time interval from 18 months to each refueling interval for TS 4.4.ll.2.a, b, and c is acceptable.
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4.0 STATE CONSULTATION
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Inaccordance$sith'theCommission'sregulations[theConnecticutState official was notif.ied of. the proposed ssuange' of the amendment. The State official had no' comments.
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5.0 ENVIRONMENTAL CONSIDERATION
l' The amendment 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, sf 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 58402 dated November 27,1995). 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.
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6.0 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 activities will be conducted in compliance with the Commission's regulations, i
and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
j Principal Contributors: K. Desai J. Andersen Date: February 19, 1997 e
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