Equipment Failure Procedure

ED-52 Electrical Distribution System 10/22/62

A. One TG is Inoperative

• 1. Start and share load with both ADG's.
• 2. Operate with "TG to Auto Sync." Selector switch in the appropriate "TG Run" position.
• 3. Verify that EDG and Emerg. Bus ABT's are set for Auto operation.
• 4. Should the generating capacity available fall below 1500 KW with the failure of other generating units, shutdown the reactor, reduce the electrical load to within the generator capacities.
• 5. Isolate, tag controls and repair defective units.

B. An ABT for Group Control A1, A2, C1, or C2 Becomes Inoperative to Transfer Automatically

• 1. Check that the equivalent other group control ABT is set for auto operation.
• 2. Switch operate to alternate equipment from the group control with the defective ABT to the operable one. Stay within the total load limitations of the feeder breakers.
• 3. Place defective ABT control in manual.
• 4. Tag defective ABT and repair during plant shutdown.
• 5. Should the operating equivalent ABT fail, shutdown to repair both units.

C. An ABT for Group Control D1 or D2 Becomes Inoperative To Transfer Automatically

• 1. Transfer the loads in operation from the group control with the faulty ABT to the good one.
• 2. Manually transfer the faulty ABT to the emergency position and put its control on manual. Tag the ABT.
• 3. Verify that the Emergency Bus feeder is closed.
• 4. Retransfer operating loads to the group control on manual ABT control.
• 5. Should the second D1 or D2 ABT fail repeat the above procedure to place it in Manual and fed by the Emergency Bus feeder.

D. One DC/AC MG Set Shutdown

• 1. Isolate and repair the defective MG unit.
• 2. Should the operating unit fail, vital bus power will be lost and the loads fed by it will de-energize. The reactor will scram, start the DK system and monitor RMS points manually.

E. One AC/DC MG Set Inoperative

• 1. Verify that the battery is fully charged by giving it a "Charge Check". Record battery current vs. time with DC bus voltage at 142 1/2 volts.
• 2. Tag controls for defective unit to prevent inadvertent use.
• 3. Should the operating AC/DC set fail, shut down the reactor when the battery can supply one more hour of operation. Reduce vital bus loads and use one DC/AC MG set during the shutdown. See item F below for Battery requirements.

F. Battery Less Than Fully Charged

• 1. Operation of the reactor may continue with the battery in use until the battery voltage decreases to 112 volts but not to exceed one hour. This requires that the battery be fully charged at the start.
• 2. IF the battery was not fully charged, or the state of charge not known at the time the battery use began, shutdown the reactor, shutdown one DC/AC unit and reduce vital bus loads as follows:
  • a. Open 11P107 when both ADG's are operating and parallel to the main bus.
  • b. Open "F" bus breakers on GE cubicle with all rods are in and carriages have followed up.
  • c. Open switches on RMS cabinets as supplementary monitoring means are available.

    NOTE: DO NOT de-energize 4P, 5P, or 12P 107 circuit breakers as these feed the Nuclear Instrumentation cabinets, containment isolation system and other systems instrumentation.

G. One ADG Inoperative With Both TG's Running

• 1. Isolate unit including cranking air line, tag controls and switchboard.
• 2. Test starting and paralleling ability of operable ADG and restore it to standby status.
• 3. Test starting of EDG and restore to standby.
• 4. Transfer alternate equipment group control loads to the main bus section with the good ADG.
• 5. Should a TG become inoperative start the good ADG. Reduce the electrical load to within the generator capacities. The reactor must be shutdown if generating capacity falls below 1500 KW.
• 6. Should the other ADG become inoperative defeat the ADG auto start circuits isolate the ADG and continue operating on two TG's. Reduce non-vital loads and limit load switching. Verify shore power availability when at the dock. Monitor TG operation for possible failure.

H. Besler Boiler Operation

• 1. The Besler boilers may be used to supply steam to drive one or two TG's when the reactor is at zero power and producing no steam provided both ADG's are operating and paralleled.
• 2. When the reactor is shutdown, the Besler boilers and TG's may supply the electrical load provided the ADG's can act as electrical backup.
• 3. When the reactor is supplying steam, the boilers are to be shutdown and on standby.

I. Ground on Any Reactor Circuit

• 1. All grounds should be cleared before reactor startup.
• 2. IF the ground can be located to equipment which is backed up by an alternate, switch to the alternate and correct the ground.
• 3. IF the ground is on 14P107 (F Bus), P118 (C bus), 12P107 (Vital Bus Feed to Aux. A), P112 (Ship's 120V Bus to Aux A), the Instrumentation DC But or the Instrumentation AC bus, shutdown the reactor and correct the ground.