ML20233A322

Comment (4) e-mail from D. Lochbaum Regarding Diablo Canyon Exigent LAR

ML20233A322
Person / Time
Site:	Diablo Canyon
Issue date:	08/18/2020
From:	Lochbaum D - No Known Affiliation
To:	Blanch P Plant Licensing Branch IV
Lee S, 301-415-3158
References
Download: ML20233A322 (2)

Text

Lee, Samson From: David Lochbaum <davelochbaum@gmail.com>

Sent: Tuesday, August 18, 2020 7:03 AM To: pmblanch@comcast.net Cc: Linda Seeley <lindaseeley@gmail.com>; Raspa, Rossana <Rossana.Raspa@nrc.gov>; Spicher, Terri

<Terri.Spicher@nrc.gov>; Morris, Scott <Scott.Morris@nrc.gov>

Subject:

[External_Sender] Diablo Canyon's exigent LAR Hello Paul:

According to the highlighted passages on page 7 of the 22-page attachment to PG&E's license amendment request, workers discovered a 3.9 gallon per minute leak from a section of AFW piping on Unit 2 last month. I'm impressed -- I can't tell you how many times I've mistaken a 3.9 gpm leak for a 4 gpm leak.

1

In any case, workers conducted an extent of condition and found no more puddles under Unit 2 AFW pipes. But they found six pipe sections where the wall thickness had dropped below minimum allowed by the ASME code. Those thinned sections were replaced.

The license amendment request seeks to allow workers to find and fix thinned pipe sections PG&E expects to exist on Unit 1's AFW system.

What is not explained in the license amendment request is why it took a 3.9 gpm leak for workers to notice thinned AFW piping on Unit 2.

Attached are just a small, small handful of the many, man NRC's correspondence to plant owners about pipe wall thinning. Thinned pipe sections that ruptured have killed workers at Surry in Virginia and Mihima in Japan. Both to avoid killing workers and to keep cooling water inside pipes instead of on floors, the NRC required -- not suggested, but required -- owners implement pipe wall thickness monitoring programs that replace pipe sections BEFORE their wall thickness drops below ASME allowables. Waiting until notices observe a 3.9 gpm leak is NOT one of the monitoring programs permitted by the NRC. And yet, ....

So, how did so many AFW pipes on Unit 2 thin below ASME allowable limits? And why are AFW pipe sections suspected of intolerable thinning on Unit 1? If PG&E was implementing an effective pipe wall thinning monitoring program, these sections would have been detected and remedied before leaking water on the floor. But nooooo!

So, for not doing what the NRC repeatedly mandated them to do, PG&E wants the NRC's permission to keep operating Unit 1 while it plays catch up. Maybe crime does pay, after all.

Thanks, Dave Lochbaum 2