ML20055J432
| ML20055J432 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 07/27/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20055J428 | List: |
| References | |
| NUDOCS 9008020252 | |
| Download: ML20055J432 (4) | |
Text
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WASHINGTON, D. C. 20666 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 55 TO FACILITY OPERATING LICENSE NO. NPF-30 UNION ELECTRIC COMPANY CALLAWAY PLANT UNIT 1 DOCKET NO. 5TN 50-483 2
1.0 INTRODUCTION
By letter dated March 6,1990 (Ref.1) the Union Electric Company (the licensee)proposedchanges.totheTechnicalSpecifications(TSs)forthe Callaway Plant. The proposed changes would add additional conditions to i
the Limiting Conditions for Operation (LCOs) to address flowpath requirements of the motor-driven andisteam turbine-driven auxiliary feedwater(AFW) pumps. Additionally, the proposed TS would provide further ACTION Statements to address situations where an Essential Service Water
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(ESW) system valve to the steam turbine-driven AFW pump became inoperable or if one ESW loop is inoperable.
2.0 DISCUSSION The-licensee's proposed revision to the TSs would add additional conditions to the LCOs for the AFW pump flowpaths and steam turbine-driven AFW pump supply. Specifically, the proposal would ensure that an adequate steam supply for the steam turbine-driven AFW pump is available from both loops and that the associated flowpaths for all the AFW pumps are capable of-performing their intended functions. The amendment aims to provide a more complete definition of system operability and should contribute to increased clarity and consistancy in the TSs for operation of the Callaway Plant.
The licensees' proposed amendment also modifies the ACTION Statements'to provide direction in the event a selected ESW supply valve to the steam turbine-driven AFW pump or an ESW loop becomes inoperable. Additionally, the proposed ACTION Statements b. and c. provide clear guidance on AFW pump operability from flowpath component inoperable conditions.
3.0 EVALUATION Specification 3.7.1.2 addresses the requirement of having three independent steam generator AFW pumps and associated flowpaths operable with the plant in modes 1, 2 and 3.
Individual changes to the TSs for the Callaway Plant are discussed below:
(1) Specification 3.7.1.2b. addressing the steam supply requirements for the steam turbine-driven AFW pump has been modified to clearly indicate that both steam supply systems need to be available to ensure system operability.
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(2) Specification 3.7.1.2c. has been added to clarify the operability requirements and definition of the associated flowpaths for the motor.-driven AFW pumps. Specifically, the associated flowpath consists of a suction from the Condensate Storage Tank-(CST) capable' of automatically transferring to an OPERABLE ESW supply and discharge to two steam generators.
(3) Specification 3.7.1.2d. has been added to provide clarification of the operability requirements of the associated flowpaths for the steam turbine-driven AFW pump. The associated flowpath consists of a suction from the CST capable of automatically transferring to two separate OPERABLE ESW supplies and discharging to all four steam generators.
The proposed changes above are consistent with the current interpretation of the Callaway TSs and are for clarification only. Since the intent of the original TSs is~not changed and the proposed improvements merely provide a more concise definition for the LCOs in Specification 3.7.1.2 the staff concludes that these changes are acceptable.
Additionally, changes to the ACTION Statements for TS 3.7.1.2 are proposed. ACTION Statements b., c. and d. are added as follows:
4 (1) ACTION Statement b., "With any part of the associated flowpath for a motor-driven auxiliary feedwater pump inoperable *,:the associated pump shall be declared inoperable and ACTIONS a., e., or f. satisfied as applicable." is added providing a more concise definition of when a motor-driven AFW becomes inoperable and the followup actions I
required.
ACTION Statement b. combined with the definition of
" associated flowpath" in-TS 3.7.1.2.c. provides clarity for entering l
the original TS ACTION Statements.
(2) ACTION Statement c., "With one of the Essential Service Water flowpaths to the turbine-driven auxiliary feedwater pump inoperable *,
restore the required supply flowpaths to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least iOT STANDBY within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />"-
originates within the Callaway seismic design commitment to Regulatory Guide 1.29 in Final' Safety Analysis Report (FSAR) Table 3.2-3,- stating that all plant components need to be capable of coping with a secondary pipe break inside containment.
The'Ca11away Plant Condensate Storage Tank (CST) is not a seismically-Category I qualified component-and therefore could not be assumed to mitigate a postulated pipe break during a design basis seismic event.. If the CST was assumed to be unavailable following a seismic event, both ESW trains would need to be operable to satisfy the single failure criterion, thus the proposed ACTION Statement above. The Callaway design basis (FSAR Section 10.4.9.3) does not postulate breaks in Category I piping (e.g.,
secondary side pipe breaks inside containment) during a seismic event, r
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- The result is the licensee's non-mechanistic characterization of the CST unavailability during the design basis seismic scenario. The licensee asserts in its safety evaluation that a postulated single ESW valve inoper-ability would not cause the steam turbine-driven AFW to becoma inoperable.
This interpretation is consistent with the licensing basis of the Callaway Plant and is acceptable in light of the proposed ACTION Statement requiring i_
operability within the 72-hour window. This change would allow a distinction between AFW pump inoperability and AFW flowpath inoperability, both of which have the same action statement. The actual change in the TSs occurs when an.
ESW loop is taken out of service and the Callaway plant enters TS'3.8.1.1.
ACTION Statement d. concerning diesel generator operability. The current TSs are subject to interpretation, one of which forces the Callaway plant into the-2-hour ACTION Statement 3.8.1.1.d.2.
(3) Action Statement d.
"With the associated flowpaths for.the-turbine-driven auxiliary feedwater pump inoperable, other than as described in ACTION c., the turbine-driven auxiliary feedwater pump shall be declared inoperable, and ACTIONS a.,
e., or f.
satisfied as applicable" is added to make clear that loss of the CST rather than an ESW flow path to the Turbine-driven auxiliary feedwater pump requires declaring the turbine-driven auxiliary feedwater_ pump inoperable and I
taking the appropriate action for an inoperable' auxiliary feedwater l
pump.
1 The staff has reviewed the above proposed change to the TS and concludes that the original intent of the TS h?s been maintained and that the changes proposed would serve to clarify the TSs. Therefore, the staff finds that the proposed TS changes are acceptable.
l-4.0- ENVIRONMENTAL CONSIDERATION This amendment involves a change to a requirement with respect to the instal-lation or use of a facility component located within the restricted area as-defined in 10 CFR Part 20 or a change to a surveillance requirement. The, staff has determined that the amendment involves no significant increase in the amounts, and no significant change-in the typec, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. :Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forthin10CFR51.22(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 this amendment.
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. S.0 CONCLUSION j
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The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the.
i will not be endangered by operation in the proposed manner; and (2) public l
such activities will be conducted in compliance with the Commission's regulations l
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.
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i Principal Contributor:
A. T. Gody, Jr.
Dated:
July 27, 1990 l
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