RCA

Jan 28....I sent the 2.206 and within two days VY admitted another leak.

...Buildings in plume being explosive hazard...was the DG threatened.

...Has the gaseous tritium been accounted for...about 3 curies.?

...How about a hydrogen detonation of the drain pit building or any nearby buildings where hydrogen and oxygen can seep into?

..Entergy's causal evaluation identified deficiencies involving not having satisfied early-1970s non-safety-related construction and housekeeping standards, and weaknesses in the station's erosion/corrosion program.



...The Entergy report identified "(t)he ineffective monitoring and inspection of the leakage control system of the AOG pipe tunnel, i.e., the tunnel floor drain and sump

pump" as the second root cause.


Entergy's RCA:

RC1: Latent Standards and Practices That Were Inadequate

Inadequate housekeeping standards and practices were applied during the construction of the AOG Pipe Tunnel in 1972. Inadequate design and installation standards and practices were applied during the installation of the 2”CNPE-172A line in 1978. These latent issues combined to compromise the leak tight design of the AOG Pipe Tunnel and allow for water containing radio nuclides to leak to the environment.

NRC:
Root Cause No.1: Latent Standards and Practices That Were Inadequate

The Entergy report stated: "Inadequate housekeeping standards and practices were applied during the construction of the AOG pipe tunnel in 1972. Inadequate design and installation standards and practices were applied during the installation of the two-inch drain line CNPE-172A in 1978. These latent issues combined to compromise the leak tight design of the AOG pipe tunnel and allowed for water containing radionuclides to leak to the environment."

The inspectors concluded that the licensee's first root cause was well-supported.

Corrective actions planned were appropriate to the circumstances and included:

1) clearing of obstructions and removal of debris to the extent possible in the AOG pipe tunnel, completed prior to AOG system startup; and, 2) redesign and implement the removal from service (by sealing) of the two-inch drain line CNPE-172A. This action was completed in June 2010. The inspector reviewed Engineering Change(EC) 22659 developed to seal drain line CNPE-172A.

It is interesting...Entergy didn't submit a voluntary LER on it...