On Thursday, August 5, 2021, during a routine University of
Utah Training Reactor (
UUTR) operation, an 'out of Technical Specification' indicator reading by water quality sensors for pH and conductivity occurred following shutdown. No other issues were noted, and the reactor and facility are secure.
Description of Event: At the end of the reactor run, UUTR operators recorded sensor pH as 5.15, pre-demineralizer conductivity was 6.444 micro-mhos/cm, and post-demineralizer conductivity was 0.054 micro-mhos/cm. UUTR Technical Specifications state that the Limiting Condition of Operation (LCO) for pH must fall between 5.5 and 7.5, with a conductivity less than 5.000 micro-mhos/cm. During the start-up procedure, the pH was recorded as 5.6, and pre-demineralizer conductivity was 4.247 micro-mhos/cm, with post-demineralizer conductivity of 0.054 micro-mhos/cm, within UUTR Technical Specifications. It was noted that pH was lower than normal, and conductivity was higher than normal, and this was attributed to the addition of algaecide water treatment actions approximately 10 days prior to the reactor pool, as prolonged maintenance outages led to a need to treat pool water to mitigate algae.
Response to this Event: Following reactor shutdown on August 5, 2021, the reactor pool clean-up loop was circulated overnight, Thursday to Friday, August 6th 2021, to enable water quality parameters to return to normal acceptable levels.
Follow-up Actions:
UUTR reactor personnel will be inspecting the pool tank on Monday, August 9, 2021, using underwater camera equipment for out of ordinary tank degradation (none is currently apparent). They will also use an external pool cleanup pump to remove any noticeable debris from the bottom of the pool tank, a process last performed June 2020. It is expected that longer run times of the pool circuit cleanup pump and cleaning actions will enable water quality parameters to return to normal operating ranges.