Glass Half Full? Glass Half Empty?

April 30, 2010
Dave Lochbaum
Former contributor

NRC Must Get Off Its Glass and Protect Americans from a Known Safety Problem

The Nuclear Regulatory Commission is mailing out letters to the owners of 34 of the nation’s 69 pressurized water reactors (PWRs). The NRC has questions about the evaluations these owners performed regarding containment sump concerns. The good news is that the NRC is satisfied with how these concerns were addressed at the remaining 35 PWRs.

But unanswered safety questions at half of the PWR fleet is simply unaccept- able at this late date. The NRC formally initiated Generic Safety Issue 191 (GSI-191) in September 1996. They categorized it as a high priority safety concern. The problem: if a pipe broke inside a PWR containment building, the force of the fluid jetting out from the broken pipe ends would scour insulation off piping, coatings off equipment, and even paint off walls. The leaked water would then carry this debris down to the basement where it would collect on metal screens. The emergency pumps used to cool PWR reactor cores during such an accident initially transfer water from large storage tanks out back. When those tanks empty, the emergency pumps swap over to get their water from that collecting in the containment basements. But the debris clogging the screens would prevent the pumps from getting enough water to cool the reactor core; hence the high priority safety concern.

Eight years later, the NRC required plant owners to take measures to resolve GSI-191 and correct this safety problem.

Nearly six years after the fix was mandated, only half of the PWR fleet has resolved this known safety problem. There is simply no excuse for this high priority safety issue being unresolved at this time. The only reason you can’t say the NRC is dragging its feet on this issue is that there has to be motion for there to be dragging.

If a pipe inside containment at one of these 34 PWRs were to occur, the people living nearby can kiss their glass goodbye – the emergency pumps may fail to cool the reactor core.

And this problem did not first surface in September 1996. The NRC informed President Jimmy Carter about it on Valentine’s Day 1979. So, a mere thirty-one years after the NRC informed the White House about a serious safety problem, only half of the PWR fleet have fixed it.

UCS chronicled this debacle in “Regulatory Malpractice: NRC’s Handling of the PWR Containment Sump Problem

Among other revelations, this report quotes the NRC explaining how it developed its program for handling generic safety problems such as GSI-191 intentionally to accommodate the nuclear industry’s need to operate reactors without resolving known safety issues. The NRC’s generic safety program allows reactors to continue operating for years, nay decades, with known safety problems as long as there is an IOU to fix them at some future date, if convenient. Shame on the NRC for instituting and then sustaining this despicable practice.

If the NRC were ever accused of being an effective regulator, they could not be convicted. And that’s even if the insanity plea were disallowed.

This is a table from a Sandia report on the chances that the containment sump screens would be blocked for the PWRs (names withheld to protect the guilty) for a small-break loss of coolant accident (SLOCA), medium sized loss of coolant accident (MLOCA), and large break loss of coolant accident LLOCA). According to Sandia, it was “VERY LIKELY” that a large break loss of coolant accident at 53 of the nation’s PWRs would result in the screens clogging and the emergency pumps failing.

Davis-Besse was in that category. Had the hole in its reactor head opened up, the emergency pumps would have tried but failed to provide makeup water to the uncovered reactor core.

The Sandia report can be found at the NRC’s online library. Click “Begin ADAMS Search” and enter ML022470076 in the search box. The search returns two hits, the second of which is the Sandia report.