ML20205L205
| ML20205L205 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/26/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20205L197 | List: |
| References | |
| NUDOCS 8811010510 | |
| Download: ML20205L205 (4) | |
Text
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'o UNITED STATES 8
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9; WASHINGTON, D. C. 20655 g.....,/
SAFETY EVALUATION BY THE 0?FICE OF NUCLEAR REACTOR REGULATION I
SUPPORTING AMENDMENT NO.101 TO PROVISIONAL OPERATING LICENSE NO. DPT 19 AND AMENDMENT NO. 97 TO FACILITY OPERATING LICENSE NO. DPR-25 COMMONWEALTH EDISON COMPANY DRESDEN NUCLEAR POWER STATION, UNIT NOS. 2 AND 3
@CKETNOS.50-237AND50-249
1.0 INTRODUCTION
By letter dated August 31, 1988, the Commonwealth Edison Company (CECO or the licensee) proposed to amend Appendix A of Provisional Operating License (POL) No. DPR-19 and Fdc111ty Operating License No. DPR-25. The letter provided infonnation to support changes to Section 3.5.F of the Technical Specifications.
The present Dresden Technical Specification 3.5.F.3 allows all low pressure core and containment cooling systems to be inoperable while in cold shutdown provided no work is being done which has the potential for draining the reactor vessel. However, the present requirements do not adcress specific Emergency Core Cooling Systems (ECCS) operability requirements during the cold shutdown or refueling operational modes.
The proposed change will rewrite the present Technical Specification 1.5.F.3 and replace it with more prescriptive requirements for ECCS operability during cold shutdown and refueling. The proposed Technical Specification will be applicable when the reactor is in the cold shutdown l
or refueling conditions with irradiated fuel in the reactor vessel and will require at least two pumps of low pressure ECCS to be operable along with an operable flow path for each pump taking suction from the suppression pool or the coridensate storage tank and transferring water to the reactor vessel. These pumps can be two Core Spray pumps, two Low Pressure Coolant Injection (LPCI) pumps, or a Core Spray pump and a LPCI pump.
Proposed Technical Specifications 3.5.F.4 and 3.5.F.5 will provide action requirements if one or both of the required ECCS are inoperable. Proposed Technical Specification 3.5.F.6 allows all low pressure core and containment cooling subsystems to be inoperable when the reactor is in the cold shutdown or refueling conditions and irradiated fuel is in the reactor vessel, provided that the reactor vessel head is removed, the reactor cavity is flooded, and the spend fuel pool water level is main tained above the low level alann point with the pool to cavity gates removed.
0011010510 001026 DR ADOCK 050 7
. 2.0 EVALUATION The present Dresden Technical Specifications require LPCI and both Core Spray subsystems to be operable whenever irradiated fuel is in the reactor vessel with an exception being that all the subsystems may be inoperable in cold shutdown provided no work is being done which has the potential for draining the reactor vessel. Also, containment cooling is required whenever irradiated fuel is in the reactor vessel and reactor coolant temperature is greater than 212*F with the same exception as for the LPCI and Core Spray subsystems while in the cold shutdown mode. The proposed change to Technical Specification 3.5.F.3 would require at least two low pressure ECCS pumps to be operable when irradiated fuel is in the reactor vessel and the reactor is in the cold shutdown or refueling mode of operation.
In addition, three new sections have been added to Section 3.5.F of the Technical Specifications (Sections 3.5.F.4 thru 3.5.F.6) and the remaining sections renumbared.
The proposed action requirements of Technical Specification 3.5.F.4 would not allow operations with a potential for draining the reactor vessel to continue if one of the required pumps and/or associated flow paths of ECCS is inoperable for more than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Proposed action requirements in Technical Specification 3.5.F.5 apply if both of the required ECCS pumps and/or flow paths are inoperable. With both of the ECCS pumps and/or flow path (s) inoperable, core alterations and all operations with a potential for draining the reactor vessel woulu 5e suspended. At least one of the required ECCS pumps and associated flow path would have to be returned to operable status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or secondary containment integrity would have to be established within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
Proposed Specification 3.5.F.6 is similar to present Technical Specification 3.5.F.3 in that all low pressure core and containment cooling subsystems are allowed to be inoperable in cold shutdown. However, the proposed change would add the refueling condition and also include the restrictions of having the reactor vessel head removed, the cavity flooded, the spent fuel pool gates removed, and fuel pool water level maintained above the low lovel alarm point.
The proposed changes to the Dre: den Technical Specifications would specifically identify the operability requirements for the low pressure ECCS equipment and containment cooling subsystem during both the cold shutdown and the refueling modes of operation.
The current Technical Specifications only pennit the low pressure ECCS equipment and containment cooling subsystems to be inoperable provided no work is being done which has the potential for draining the reactor vessel. Under the proposed changes, any combination of two core spray pumps or low pressure coolant inspection pumps would be reauired to be operable during the cold shutdown or refueling modes of operation. Although this IF less than required by the current Technical Specifications since the primary system is not pressurized in the cold shutdown or refueling modes and the decay heat generatinn rate is significantly less than imediately following reactor power operation, the ECCS water makeup requirements are also significantly less.
1 The 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> pemitted by the proposed Technical Specifications to restore to operability one of the two required ECCS pumps without suspending operations is reasonable since it is of sufficiently short duration that the probability of an accident that would result in the draining of the reactor vessel during this period is small.
Similarly the 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> permitted to restore operability of one of the ECCS pumps, if all are inoperable, before requiring secondary containment integrity to be established within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, is also reasonable considering the fact all operations with a potential for draining the reactor are inrnediately suspended.
The proposed Technical Specification changes include the refueling mode which is not specifically addressed in the current Technical Specifications and additional restrictions that ensure that with all the low pressure ECCS and containment cooling subsystem inoperable during the cold shutdown and refueling operational modes the potential for inadvertently draining the reactor vessel has been eliminated.
Based on its review of the information provide by CECO, the staff has detemined the following:
(1) The proposed Technical Specification changes maintain the necessary ECCS equipment available to provide makeup water to the reactor vessel in the cold shutdown and refueling operational modes; (2) The proposed Technical Specification action conditions ensure that operations with a potential for draining the reactor vessel, or core alterations are not performed without ECCS makeup capability or the reactor csvity maintained above the fuel pool low level alarm point; (3) The proposed Technical Specification changes assure that secondary containment integrity is established if two ECCS pumps and assoClated flow paths are not available; (4) Although the proposed Technical Specifications would allow fewer ECCS systens to be required operable in the cold shutdown and refueling operational modes, the present Technical Specifications are overly restrictive since they do not reflect the smaller water makeup requiremonts for cold shutdown and refueling compared to pressurized power operational conditions. The necessary ECCS water makeup capability for cold shutdown and refueling operational modes is being maintained and additional restrictions are being imposed by CECO before taking all the low pressure ECCS and containment cooling systems out of service; and (5) The proposed Technical Specifications follow the Standard Plant and later BWR operating plant (i.e. LaSalle) requirements for ECCS systems during the same operational modes.
Based on the above conclusions, the staff has determined that the Technical Specification changes proposed by CECO for Dresden Unit Nos. 2 and 3 for the cold shutdown and refueling operational modes are acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has detemined 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 occupational radiation exposure. The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, these amendments meet 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 nor environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The staff has concluded, based on the consideration discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the prooosed manner, and (2) such activities will be conducted in compliance with the Comission's regulations and the issuance of these amendments will not be inimical to the comon defense and security nor to the health and safety of the public.
Principal Contributor:
Byron Siegel Dated:
October 26, 1988 1
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