ML20137X107
| ML20137X107 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/14/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20137X103 | List: |
| References | |
| NUDOCS 9704210161 | |
| Download: ML20137X107 (5) | |
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UNITED STATES l
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066 4001 49.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 190 TO FACILITY OPERATING LICENSE NO. DPR-16 GPU NUCLEAR CORPORATION AND JERSEY CENTRAL POWER & LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219
1.0 INTRODUCTION
By letter dated October 10, 1996, the GPU Nuclear Corporation (the licensee) requested an amendment to the Technical Specifications (TSs) appended to i
Facility Operating License No. DPR-16 for the Oyster Creek Nuclear Generating Station. The requested changes would:
1.
replace the present interlock description "AC Voltage" with " Core Spray Booster Pump d/p Permissive: >21.2 psid" as a permissive for initiation of the automatic depressurization system (ADS), for Function Unit G.3 of TS Table 3.1.1, 2.
add' applicable reactor modes under which the permissive of Function Unit G.3 must be functional, 3.
add corresponding surveillance requirement to TS Table 4.1.1 to test and calibrate the core spray booster pump differential pressure (d/p) switches pursuant to existing plant procedures, and 4.
revise existing footnotes for the ADS initiation functions and provide new footnotes to identify the interlock function which always existed but was not clearly identified in the TS and, define operability and allowed outage times (A0T) for the interlock d/p switches.
The ADS is designed to provide for a controlled blowdown of the primary system in order to reduce reactor pressure rapidly during a small pipe break event which will allow core injection prior to uncovering the fuel. ADS is automatically initiated on low-low-low reactor water level coincident with high drywell pressure and with core spray injection booster pump d/p switch as a permissive interlock. The d/p switch permissive-interlock ensures that 9704210161 970414 PDR ADOCK 05000219 P
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j cooling water for the injection function is available prior to depressurization of the reactor. This permissive is similar to the Im Standard TS requirement to monitor core spray pump discharge pressure. proved t
In its submittal, the licensee stated that the d/p switch interlock function was incorporated in the ADS logic design in 1985 but was not identified clearly in the existing TS. The proposed amendment identifies the functional i
requirements of this interlock for the TS.
1 2.0 EVALUATION l
2.1 Pronosed chanae: Table 3.1.1, Protective Instrumentation Requirements, j
revise Function G, Automatic Depressurization, item 3 to read: " Core Spray Booster Pump d/p Permissive [s): > 21.2 psid."
Revise the table to require that the d/p instrument channels be operable during the shutdown and refuel modes, consistent with the mode applicability of both the High Drywell Pressure and the Low-Low-Low Reactor Water Level initiation signals required for ADS actuation.
Evaluation:
For the ADS to provide its protective function, i.e., opening of the electromatic relief valves (EMRVs) and blowdown to the torus to reduce pressure following a small break LOCA, both initiation signals (high drywell pressure and low-low-low reactor level) must be tripped in conjunction with a permissive-interlock indicating that the core spray system (CSS) is available.
Availability of the CSS is indicated by the booster pump d/p switches.
In its submittal, the licensee stated that the TS limit for d/p >21.2 psid was established by determining both upper and lower safety limits for actuation by using established calculation methodologies to ensure that adequate margins would be available to account for the potential of pump run out, instrument error, drift, switch reset dead bands, potential pump failure, and electrical transients associated with a pump trip or a pump start.
The proposed TS revision does not modify the ADS design nor does it change instrument setpoints but identifies the functional requirements of the existing d/p switch interlock as part of the protective system actuation requirement in the TS. This modification is acceptable to the staff.
2.2 Prooosed chanae: Table 3.1.1, Protective Instrumentation Requirements, item G - Automatic Depressurization, Function 3, add a new footnote "i" to read:
"With two core sorav systems OPERABLE:
1.
A maximum of two core spray booster pump differential pressure (d/p) switches may be inoperable provided that the switches are in opposing ADS trip systems [i.e., p.n].y: either RV-40 A&D or RV-40 B&C).
Place the relay contacts associated with the inoperable d/p switch (es) in the de-energized position, within 24
. hours. Restore the inoperable d/p switch (es) within 8 days, or declare ADS inoperable and take the action required by Specification 3.4.B.3; or, 2.
If two inoperable d/p switches are in the same ADS trip system
[i.e., RV-40 A&B or RV-40 C&D), place the relay contacts associated with the inoperable d/p~ switch (es) in the de-energized position, within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Restore the inoperable d/p switches within 4 days, or declare ADS inoperable and take the actit,n required by Specification 3.4.B.3.
With only one core sorav system OPERABLE If one or more d/p switches become inoperable in the OPERABLE core spray system, declare ADS inoperable and take the action required by Specification 3.4.B.3."
Evaluation: In its submittal, the licensee stated that the new Footnote "1" is provided to specify the operator action (s) required when failure of a core spray booster pump d/p switch occurs.
Footnote "i" also takes into account the redundancy of the d/p switches in the as-built configuration, i.e., the fact that each of the two d operation of both core spray /p switches provided in each CSS monitors the booster pumps simultaneously.
If one of the two core spray booster pump d/p switches were to fail in either CSS-I or CSS-II or both (A&D or B&C), monitoring of both pairs of redundant booster pumps in each of the respective CCS would continue to be accomplished by the redundant d/p switches in each system that remain operable. A maximum of 8 days is allowed to perform repairs under these conditions.
Placing the relay contacts for the failed d/p switch in the "de-energized" state ensures that the redundant d/p switch performs the function of monitoring operability of either of the redundant booster pumps, such that ADS is prevented from being inadvertently initiated.
As per new note "i", if one of the two ADS divisions becomes inoperable due to i
inoperability of one or more (A&B or C&D) d/p switch (es), a maximum of 4 days is allowed to perform repairs. Thus, the plant can operate 4 days with only one ADS train available.
In this situation, if a single failure occurs in one of the two operable d/p switches, an operable ADS train will still be available in the presence of a single failure, because the last operable d/p switch can monitor both booster pumps of the operable CSS-I or CSS-II (as the case may be). The 8-day and 4-day A0Ts for the inoperable d/p switches are consistent with those for other ADS protective system functions in the Oyster Creek TS. Note "i" as discussed above is, therefore, acceptable to the staff.
2.3 Proposed chanae: Table 3.1.1, Protective Instrumentation Requirements, item G - Automatic Depressurization, Functions 1 and 2, revise footnote "h" to read:
"With one or more instrument channel (s) inoperable in one ADS trip system, place the relay contact (s) for the inoperable initiation signal in the tripped
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. condition within 4 days, or declare ADS inoperable and take the action required by Specification 3.4.B.3.
With one or more instrument channel (s) inoperable in both ADS trip systems, restore ADS initiation capability in at least one trip system within I hour, or declare ADS inoperable and take the action required by Specification 3.4.B.3.
Relief valve controllers shall not be bypassed fo any more than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> (total time for all controllers) in any 30-day period and only one relief valve controller may be bypassed at a time."
Evaluation: The licensee stated that Footnote "h." is revised to change the A0Ts associated with the initiating signals of High Drywell Pressure or Low-Low-Low Reactor Water Level (Items G.1 and G.2 on Table 3.1.1) to align them with the surveillance test intervals and A0Ts for the ADS.
Of note, the Improved Standard Technical Specifications (ISTS) allow channel inoperability which does not result in a loss of function to continue for an indefinite period. This is based on the reliability analyses performed on the ADS and continued operability of the ADS assuming a single failure when an inoperable channel is placed into the tripped condition.
The revised Footnote "h." clarifies specifically what operator action is required with respect to placing the inoperable instrument channel in the ADS initiation circuit in a tripped state.
The previous wording in Footnote "h."
indicated that "One instrument channel in each trip system may be inoperable provided 'the circuit which it operates in the trip system is placed in a simulated tripped condition'...." As a result of the above proposed change, any confusion related to the phrase in single quote marks above is eliminated by specifically requiring the relay contacts for the inoperable initiation signal to be placed in the tripped condition.
In case one instrument channel in each trip system is found inoperable, the existing note "h" requires the inoperable channel (s) to be placed in its tripped state. Therefore, both ADS divisions are available to perform their design function.
In accordance with the revised note "h", with one or more instrument channel (s) inoperable in one ADS trip system, the inoperable channel (s) will be placed in the tripped system within 4 days. This means that the affected ADS division will be inoperable for 4 days since the inoperable channel is not placed in the tripped state, and the plant will operate 4 days with only one ADS division available.
In this situation, if a single failure occurs during these 4 days in the available ADS train, neither division of ADS will be available. Thus, the proposed revision to Footnote "h" is nonconservative compared to the existing version.
In its submittal, the licensee stated that the ISTS allow 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> (4 days) for the A0T for the above situation. Therefore, the revision to footnote "h" was proposed to make the existing Oyster Creek TS A0T consistent with that of the ISTS. The ISTS acceptance of the longer A0T was based on the availability of diverse systems to perform the design objectives of the ADS system. Since this proposed change is consistent with the ISTS, the staff finds it acceptable.
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- i 2.4 Procosed chanae: TS Table 4.1.1, add item 31 to read:
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" Core Spray Booster Pump Differential Pressure". Add "N/A" in Check, "Once every 3 months" in Calibrate, "Once every 3 months" in Igs1 and "By application of a test pressure" in Remarks l
columns.
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Evaluation: In its submittal, the licensee stated that the new item 31 is added to the table to reflect surveillance activities such as channel check, i
calibration, and test that are associated with the core spray booster pump d/p i
switches. The performance' checks will be implemented by existing plant i
procedures. The surveillance frequencies are consistent with those j
established in Reference 2 of TS Bases Section 4.1.
This is acceptable to the staff.
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Based on the above review, the staff concludes the proposed Oyster Creek TS i
modifications for the ADS initiation function are consistent with the current j
Oyster Creek protective system TS requirements and the ISTS and are,
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therefore, acceptable.
3.0 STATE CONSULTATION
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'In accordance with the Commission's regulations, the New Jersey State official was. notified of the proposed 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 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 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 (61 FR 57485). 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 activities will be conducted in compliance with the Commission's regulations, 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.
Principal Contributor:
S. V. Athavale Date: April 14, 1997