Plant Operating Standard

SP-28 Soluble Poison

A. Condition of System During Normal Operation

• 1. Soluble poison tank is filled to operating level with demineralized water. (8" below top of the tank)
• 2. Immersion heaters are controlled by thermostat to maintain water at approximately 200F.
• 3. No more than 175 lbs. of boric acid is near the tank for use if needed.
• 4. The propeller-type agitator is operable and in standby condition.

B. Normal System Operation to Poison Reactor

• 1. Emergency makeup pump is operated for a sufficient period of time before boric acid is injected in order to warm up lines to prevent crystallization.
• 2. Boric acid crystals are added to mixing tank and dissolved in water with the aid of the agitator.
• 3. Emergency makeup pump and canned pump are used to pump boric acid solution into primary system.
• 4. The water in the soluble poison tank is maintained above 175F. after 175 lbs. of boric acid crystals are added in order to prevent crystallization.

C. Plant Condition Requiring Use of System

• 1. All other means of providing an adequate reactivity holdown margin during cooldown or xenon decay have failed. See POS-RC-04 for use of the SP System.