ML17191B252
| ML17191B252 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/18/1999 |
| From: | Rossbach L NRC (Affiliation Not Assigned) |
| To: | Kingsley O COMMONWEALTH EDISON CO. |
| References | |
| TAC-MA0383, TAC-MA0384, TAC-MA383, TAC-MA384, NUDOCS 9902240132 | |
| Download: ML17191B252 (4) | |
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J Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towe rs West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515.
SUBJECT:
TECHNICAL SPECIFICATION BASES CHANGE-DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 '(TAC NOS. MA0383 AND MA0384)
Dear Mr. Kingsley:
By letter dated December 17, 1997, as superseded by letter dated November 23, 1998, Commonwealth Edison Company (ComEd, the licensee) submitted a proposed change to Facility Operating License Nos. DPR-19 and DPR_-45, Appendix A - Technical Specifications (TS) Bases Section 3/4.9, "Electrical Power Systems." The licensee made editorial changes to the bases section to correct potentially misleading information pertaining to the function of the DC power systems during a loss of AC power.
These changes provide clarity to the Bases Section 3/4.9 and the staff has no objections to this Bases change.
Sincerely, ORIG. SIGNED GY Lawrence W. Rossbach, Project Manager Project Directorate 111-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation
- Docket Nos. 50-237 and 50-249
Enclosure:
- Bases Page B 3/4.9-6 cc w/encl: See next page DISTRIBUTION:
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UNITED STATES NUCLEAR REGULATORY COMMISSION Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515 WASHINGTON, D.C. 20555-0001
- February 18, 1999
SUBJECT:
TECHNICAL SPECIFICATION BASES CHANGE-DRESDEN NUCLEAR POWER STATION, UNITS 2AND 3 {TAC NOS. MA0383 AND MA0384)
Dear Mr. Kingsley:
By letter dated December 17, 1997, as superseded by letter dated November 23, 1998, Commonwealth Edison Company (ComEd, the licensee) submitted a proposed change to Facility Operating License Nos. DPR-19 and DPR-25, Appendix A-Technical Specifications
- {TS) Bases Section 3/4.9, "Electrical Power Systems." The licensee made editorial changes to
- the bases* section to correct potentially misleading information pertaining to the function of the DC power systems during a loss of AC power.
These changes provide clarity to the Bases Section 3/4.9 and the staff has no objections to this Bases c;:hange.
Docket Nos. 50-237 and 50-249
Enclosure:
Bases Page B 3/4.9-6 cc w/encl: See next page
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Sincerely,
- Lawrence W. Rossbach, Projeci Manager Project Directorate 111-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation
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- 0. Kingsley Commonwealth Edison Company
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Commonwealth Edison Company Site Vice President - Dresden 6500 N. Dresden Road Morris, Illinois 60450-9765 Commonwealth Edison Company Dresden Station Manager 6500 N. Dresden Road Morris, Illinois 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, Illinois 60450-9766 Regional Administrator U.S. NRC, Region Ill 801 Warrenville Road Lisle, Illinois 60532-4351 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Chairman Grundy County Board Administration Building 1320 Union Street Morris, Illinois 60450 Document Control Desk-Licensing Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Commonwealth Edison Company Reg. Assurance Manager - Dresden 6500 N. Dresden Road Morris, Illinois 60450-9765 Mr. David Helwig Senior Vice President Commonwealth Edison Company Executive Towers West 111 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515 Dresden Nuclear Power Station Units 2 and 3 Mr. Gene H. Stanl~y PWR Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515 Mr. Christopher Crane
- BWR Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515 Mr. R. M. Krich Vice President - Regulatory Services Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, Illinois 60515
- Ms. Pamela B. Stroebel Senior Vice President and General Counsel Commonwealth Edison Company P.O. Box 767 Chicago, Illinois 60690-0767
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v ELECTRICAL POWER SYSTEMS B 3/4.9 BASES Each battery of the D.C. electrical power systems is sized to start and carry the normal D.C. loads plus all D.C. loads required for safe shutdown on one unit and operations required to limit the consequences of a design basis event on the other unit for a period of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> following* loss of all offsite power plus a single active failure without taking credit for the battery chargers. The battery chargers are sized to restore the battery to full charge under normal (non-emergency) load conditions. A normally disconnected alternate 125 volt battery is also provided as a backup for each normal battery. If both units are operating, the normal 125 volt battery must be returned to service within the specified time frame since the design configuration of the alternate battery circuit is susceptible to single failure and, hence, is not as reliable as the normal station circuit. During times when the other unit is in a Cold Shutdown or Refuel condition, an alternate 125 volt battery is available to replace a normal station 125 volt battery on a continuous basis to provide a second available power source.
With one of the required D.C. electrical power subsystems inoperable the remaining system has the.
capacity to support a safe shutdown and to mitigate an accident condition. However, a subsequent worst-case single failure would result in complete loss of ESF functions. Therefore, an allowed outage time is provided based on a reasonable time* to assess plant status as a function of the inoperable D.C.
electrical power subsystem and, if the D.C. electrical power subsystem is not restored to OPERABLE status, prepare to effect an orderly and safe plant shutdown.
Inoperable chargers do not necessarily indicate that the D.C. systems are not capable of performing their post-accident functions as long as the batteries are within their specified parameter limits. With both the required charger inoperable and the battery degraded, prompt action is required to assure an
. adequate D.C. power supply.
ACTION(s) are provided to delineate the measurements and time frames needed to continue to assure OPERABILITY ofthe Station batteries when battery parameters are outside their identified limits.
Battery surveillance requirements are based on the defined battery cell parameter values. Category A defines the normal parameter limit for each designated pilot cell in each battery. The pilot cells are the average cells in the battery based on previous test results. These cells are monitored closely as an indication of battery performance. Category B defines the normal parameter limits for each connected cell. The term "connected cell" excludes any battery cell that may be jumpered out because of a degraded condition or for any other reason. Category B also defines allowable values for each connected cell. These values, although reduced, provide assurance that sufficient capacity exists to
- perform the intended function and maintain a margin of safety. When any battery parameter is outside the Category B allowable value, the assurance of sufficient capacity as described above no longer exists and the battery must be declared inoperable.
Verifying battery terminal voltage while on float charge for the batteries helps to ensure the effectiveness of the charging system and the ability of the batteries to perform their intended function. The voltage requirements are based on the nominal design voltage of the battery and are consistent with the initial voltages assumed in the battery sizing ealculations.
DRESDEN - UNITS 2 & 3 B 3/4.9-6
, Issued by letter dated fFebruary 18, 1999
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