Zinc Solution Filtration Kit

Problem

Some Pressurized Water Reactor (PWR) plants that inject zinc acetate into the reactor coolant system have observed chronic issues with the pumps used to inject the zinc solutions losing prime.  Radiological Solutions Inc. (RSI) investigated the issue and determined that some of the zinc acetate or other impurities were not fully dissolving.  Additionally, all of the plants experiencing problems were using zinc acetate from the same supplier.  Undissolved zinc or other impurities can result in the pump head check valves sticking open or closed, creating fluctuations in the injection rate or more commonly preventing injection completely.  RSI has developed a low cost and easy to implement solution to this problem, the “Zinc Solution Filtration Kit.”

Solution

The kit quickly pumps dissolved zinc through an in-line 10 micron filter and into the in-service carboy on the zinc addition skid, thus filtering out the undissolved zinc and other impurities to a level that does not impair operation of the pump check valves.  The self-priming pump rate is 2-3 liters a minute.  All fluid connections are integral to the kit with fittings designed to easily attach to the zinc addition skid carboy.  The kit operates on standard 115V power.  The lightweight and compact design allows technicians to use the filtration tool locally in the field when refilling zinc addition carboys with minimal time impact.   

The use of the Zinc Solution Filtration Kit prevents the necessity of adding an in-line filter to the suction of the zinc addition pumps which would require a modification and would restrict the available pump suction head. 

Results

This product has been provided to multiple plants across the U.S.  Before implementing use of the filtration tool, these plants were experiencing zinc addition pump loss of prime approximately every other month (about 6 a year).  No loss of pump priming problems have been reported since providing these plants with the kit in mid-2015.

Date : 10/22/2015