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Sunday, June 19, 2016

Nuclear security

Davis-Besse Leaked Reactor Cooling Water, Again

Fig. 1 (Source: NRC)
On March 30, 2016, workers found boric acid residue on a vent line from a reactor coolant pump during an inspection during a refueling outage. Davis-Besse has two steam generators and each steam generator has two reactor coolant pumps. Each pump sends about 90,000 gallons per minute from the steam generator back to the reactor vessel.
An estimated half teaspoon of dry boric acid was found on a vent line. This specific vent line had been installed during the prior refueling outage in April 2014 to replace vent lines that had worn out due to vibrations caused by the pump’s operation. Workers shipped the section of the failed vent line to a laboratory for examination, since no hole or crack was visible. Laboratory analysis could not identify a pathway for the borated water to have leaked out, but found crack indications in a weld that was the likely suspect.

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