Equipment Failure Procedure

NI-80 Nuclear Instrumentation System 10/22/62

A. Failure Of One Channel In Use

• 1. If the failure did not cause an automatic reactor shutdown, continue operation on the remaining channel (s).
• 2. Verify that the Safety System is set for "Single" safety action if this applies to the channel which failed.
• 3. Should a second channel fail, shut down the reactor for repair of both failed channels.

B. Failure of A Console Indication

• 1. Continue reactor operation as long as valid console indication is available for level and rate (where rate applies).
• 2. Correlate NI readings at the cabinets and console.
• 3. Shut the reactor down if either level or rate indications are not presented at the console for the existing operating condition.

C. Loss of Ability To Scram Or Fast Insert

• 1. Shut down the reactor if any one of the scram or fast insert functions either fails to function when the limiting plant conditions are reached or when it is known that the circuitry is such that the safety action would not occur, if the plant conditions were to reach the limit.

D. Cabinet Accessibility

• 1. No adjustments, repairs or other physical work is to be done on the Nuclear Instrumentation cabinets while the reactor is operating.
• 2. Cabinet doors are to remain closed at all times except when visual observance of the panels inside is required.

E. During Reactor Shutdown

• 1. The NI system is to remain in operation as for reactor operation except that maintenance work may be accomplished under the following conditions:
  • a. A minimum of 20 control rods fully in, carriages followed up, drive system de-energized and controls locked and tagged. No physical work being done on the drive mechanism.
  • b. PS temperature stabilized with no more than (2) pumps in operation. The other two pumps operable.
  • c. Containment RMS channel in operation.
• 2. Should power to the NI be lost -
  • a. Scram any withdrawn control rod. De-energize and lock out CDR power.
  • b. Personnel in the containment and secondary shield areas are to leave immediately and the containment be secured.
  • c. Stabilize and maintain PS temperature. Secure maintenance activities affecting the Primary or Pressurizing systems.

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  My text copyright 2020 Tommy Johnson, all rights reserved. I believe the Savannah documentation is property of MARAD or the US government.