Plant Operating Standard

NI-80 Nuclear Instrumentation and Safety

A. Normal Operations

1. All elements of the system are in operation as evidenced by:
- a. All power on lamps lighted below 10^-9 Amp in Channels 5,6, and 7.
- b. All channels functioning below an intermediate level of 10^-9 Amp.
- c. Channels 1 and 2 high voltage supplies to the BF_3 chambers secured when channels 3 and 4 indicate a count rate of more then 10 but less than 100. Corresponding power lamps for the BF_3 to indicate off.
- d. All trip and alarm lamps clear.
- e. All safety inputs connected and trips set.
2. Coincidence Panel is set for coincidence operation.
3. Scram is set for a rate of 2.8 DPM and 20% F.P. (Start Position) and 120% (Run Position).
4. Rate trip lockout, which removes the rate scram from the safety circuit, should be set at 10% FP or above.
5. Console elements: Rate and level meters together with their channel selector switches are functioning correctly. Recorders in operation.
6. Functioning of the high flux level safety circuit trips shall be tested weekly while the reactor is operating.
7. Power range channel readings must be checked against a plan heat balance at least once each voyage, but not less than once each thirty (30) day period when the reactor is operated at sea. A power level of 70% of that attainable with the operable PS pumps and loops should be held for at least twelve (12) hours prior to the test. They should be re-checked weekly thereafter during the time the power level is sustained. If the error in the power range channel readings exceeds +4% -1% FP, the instruments must be adjusted to agree with the heat balance value.

B. Minimum Condition for Reactor Operation

1. At least one correctly functioning console meter display of each class of information (rate and level) developed in a given operating range shall be available to the operator.
2. The following instrument channels shall be operating:
- a. Above 10^-9 Amp. Intermediate Range Level:
  - Two (2) Intermediate Range Channels
  - Two (2) Power Range Channels
3. At least one (1) Safety Amplifier shall be functioning at all times.