ML052000061

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Tech Spec Pages for Amendment 256 Capability Upgrade of a 69-KV Offsite Power Line to 230-KV
ML052000061
Person / Time
Site: Oyster Creek
Issue date: 07/14/2005
From:
NRC/NRR/DLPM
To:
References
TAC MC6473
Download: ML052000061 (2)


Text

Bases:

The general objective is to assure an adequate supply of power with at least one active and one standby source of power available for operation of equipment required for a safe plant shutdown, to maintain the plant in a safe shutdown condition and to operate the required engineered safety feature equipment following an accident.

AC power for shutdown and operation of engineered safety feature equipment can be provided by any of three active (one or two 230 KV lines: N-line or 0-line, the 230 KV S-line, and one of two 34.5 KV lines is active) and either of two standby (two diesel generators) sources of power.

In applying the minimum requirement of one active and one standby source of AC power, since two 230 KV lines are on the same set of towers, either one or both of the 230 KV lines (N-line or O-Line) are considered as a single active source. Normally all six sources are available.

However, to provide for maintenance and repair of equipment and still have redundancy of power sources the requirement of one active and one standby source of power was established. The plant's main generator is not given credit as a source since it is not available during shutdown.

The plant 125V DC system consists of three batteries and associated distribution system.

Batteries B and C are designated as the safety related subsystems while battery A is designated as a non-safety related subsystem. Safety related loads are supplied by batteries B and C, each with two associated full capacity chargers. One charger on each battery Is in service at all times with the second charger available in the event of charger failure. These chargers are active sources and supply the normal 125V DC requirements with the batteries and standby sources. (1)

Action 3.7.D.1 is for one required safety related battery B or battery C charger (i.e., no station battery charger operable for the associated battery) inoperable (e.g., the battery float voltage limit of 4.7.C.1.a is not maintained for battery B or battery C). These Actions provide a tiered response that focuses on returning the battery to the fully charged state and restoring a fully qualified charger to OPERABLE status in a reasonable time period. Action 3.7.D.1.a requires that the battery terminal voltage be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. This time provides for returning the inoperable charger to OPERABLE status or providing an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage. Restoring the battery terminal voltage to greater than or equal to the minimum established float voltage provides good' assurance that, within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the associated battery will be restored to its fully charged condition (as verified by Action 3.7.tD.1 .b) from any discharge that might have occurred due to the charger inoperability.

A discharged battery having terminal voltage of at least the minimum established float voltage indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus, there is good assurance of fully recharging the battery within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, avoiding a premature shutdown with its own attendant risk.

If established battery terminal float voltage cannot be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and the charger is not operating in the current-limiting mode, a faulty charger is indicated. A faulty charger that is incapable of maintaining established battery terminal float voltage does not provide assurance that it can revert to and operate properly in the current limit mode that is necessary during the recovery period following a battery discharge event that the DC system is designed for.

OYSTER CREEK 3.7-4 Amendment No.: ,6 , 99, 13G6,448-,222-,245, 256 rofted by -o151201

3.7 AUXILIARY ELECTRICAL POWER Applicability: Applies to the OPERATING status of the auxiliary electrical power supply.

Obiective: To assure the OPERABILITY of the auxiliary electrical power supply.

Specification:

NOTE: LCO 3.0.C.2 is not applicable to Auxiliary Electrical Power.

A. The reactor shall not be made critical unless all of the following requirements are satisfied:

1. The following buses or panels energized.
a. 4160 volt buses 1C and 1D in the Turbine Building Switchgear Room.
b. 460 volt buses:

USS 1A2, USS 1B2, MCC 1A21, MCC 1821, Vital MCC 1A2, and Vital MCC 1B2 in the Reactor Building 480 V Switchgear Room.

USS 1A3 and USS 1B3 in the Intake Structure.

MCC 1A21A, MCC 1A21B, MCC IB21A, MCC 1B21B, and Vital MCC 1AB2 on Reactor Building Elevation 23' 6".

MCC 1A24 and 1B24 in the Boiler House.

c. 208/120 volt panels CIP-3, IP-4, IP-4A, IP-4B, IP-4C and VACP-1 in the Reactor Building Switchgear Room.
d. 120 volt protection panels PSP-1 and PSP-2 in the Lower Cable Spreading Room.
e. 125 VDC Distribution Centers DC-B and DC-C.

125 VDC Power Panels DC-D and DC-F.

125 VDC MCCs DC-1 and DC-2

f. 24 volt DC power panels DC-A and DC-B in the Lower Cable Spreading Room.
2. One 230 KV line (N-line or O-line) is fully operational and switch gear and both I startup transformers are energized to carry power to the station 4160 volt AC buses and carry power to or away from the plant.
3. An additional source of power consisting of one of the following is in service connected to feed the appropriate plant 4160 V bus or buses:
a. 230 KV S-line fully operational. I
b. A 34.5 KV line fully operational.

OYSTER CREEK 3.7-1 Amendment No.: 11, 55, 80,4419, 136, 211,222,211,215,256 Corrected by lctter of 1/15/201