On November 1, the licensee performed boroscope inspections of the Unit 1 guard pipes associated with the encapsulated valves in the
RHR and SC systems containment
sump suction lines. The licensee initiated these inspections due to the continuing discovery of water in the encapsulations of these valves during quarterly inspections. When water was observed in the Unit 1
CS system Train B guard pipe, the licensee performed a core drill into the vertical pipe chase to which the was guard pipe attached and discovered approximately 500 gallons of water. The licensee decided to perform core drills of the remaining seven vertical pipe chases (3 on Unit 1 and 4 on Unit 2). The licensee discovered no water in the Unit 2
CS system Train A vertical pipe chase, but did discover approximately 100 gallons of water in the Unit 2
RHR system Train A vertical pipe chase. The licensee plans to assemble a team to review the chemical analysis of the water and the camera inspections of the vertical pipe chases to determine the source(s) of the water. Water entering the vertical pipe chase could communicate with the containment
sump suction isolation valve for each train of the
RHR and
CS systems and potentially render these valves
inoperable. This issue will remain unresolved pending further review of the source of water and evaluation for adverse impact on system operability and is identified as Unresolved Item (
URI) 05000348,364/2007005-01, Potential Flooding of Containment
Sump Suction Valves.
