Skip to main content

NRC Chairman Jaczko Responds to Questions from EPW Chairman Boxer on Fukushima-Daiichi

By

On March 17, Environment and Public Works Committee Chairman Barbara Boxer (D-CA) asked for a thorough review and posed a number of questions to the Nuclear Regulatory Commission on US nuclear power plants. Chairman Jaczko responded on April 8 (the pdf was posted on 4/15). Below are a few highlights from the letter:

1. Please identify all U.S. nuclear facilities subject to significant seismic activity and/or tsunamis.

Although we often think of the US as having "active" and non-active" earthquake zones, earthquakes can actually happen almost anywhere. Seismologists typically separate the US into low, moderate and high seismicity zones. The NRC requires that every nuclear plant be designed for site-specific ground motions that may be expected at their locations. In addition, the NRC has specified a minimum ground motion level to which all nuclear plants must be designed. The designation of the general type of seismic zone that may apply at any specific site is subject to interpretation but a conservative interpretation -meaning a larger zone-might include the following plants, based upon a preliminary estimate:

High Seismicity -Diablo Canyon, SONGS [San Onofre]
Moderate Seismicity -Brunswick, Robinson, Summer, Vogtle, Hatch, Clinton, Watts Bar, Sequoya, North Anna
Low Seismicity -all other plants

2. What extra safety features does the NRC currently require for facilities that have a credible threat of an earthquake or tsunami?

… With regard to the type of containment design used by the most heavily damaged plants in Japan, the NRC initiated a Boiling Water Reactor (BWR) Mark I Containment Improvement Program in the late 1980. This led to installation of hardened vent systems for containment pressure relief, as well as enhanced reliability of the automatic depressurization system.

Additionally, following the 9/11 events, reactor licensees have been required to develop strategies to maintain and restore core cooling, containment, and spent fuel pool cooling capabilities under the circumstances associated with the loss of large areas of the plant due to explosions or fire. Licensees are required to develop strategies for fire fighting, operations to mitigate fuel damage, and actions to minimize radiological release.

…

4. What increased risk is associated with exposure to mixed oxide fuel?

… NRC has evaluated the use of MOX fuel and concluded that the design basis accidents consequences were within the acceptance criteria and the differences between MOX and uranium fuel were within the dose consequences calculation uncertainties. The staff has concluded that the presence of a small number of MOX fuel assemblies in Fukushima Daiichi Unit 3 constitutes an insignificant change from non-MOX fuel in core operating conditions and accident consequences.

There are a few other answers worth checking out so be sure to stop by (pdf).

Labels:

Comments

Post a Comment

Popular posts from this blog

How Nanomaterials Can Make Nuclear Reactors Safer and More Efficient

By
The following is a guest post from Matt Wald, senior communications advisor at NEI. Follow Matt on Twitter at @MattLWald.

From the batteries in our cell phones to the clothes on our backs, "nanomaterials" that are designed molecule by molecule are working their way into our economy and our lives. Now there’s some promising work on new materials for nuclear reactors.

Reactors are a tough environment. The sub atomic particles that sustain the chain reaction, neutrons, are great for splitting additional uranium atoms, but not all of them hit a uranium atom; some of them end up in various metal components of the reactor. The metal is usually a crystalline structure, meaning it is as orderly as a ladder or a sheet of graph paper, but the neutrons rearrange the atoms, leaving some infinitesimal voids in the structure and some areas of extra density. The components literally grow, getting longer and thicker. The phenomenon is well understood and designers compensate for it with a …
1 comment
Read more

Why America Needs the MOX Facility

By
If Isaiah had been a nuclear engineer, he’d have loved this project. And the Trump Administration should too, despite the proposal to eliminate it in the FY 2018 budget.

The project is a massive factory near Aiken, S.C., that will take plutonium from the government’s arsenal and turn it into fuel for civilian power reactors. The plutonium, made by the United States during the Cold War in a competition with the Soviet Union, is now surplus, and the United States and the Russian Federation jointly agreed to reduce their stocks, to reduce the chance of its use in weapons. Over two thousand construction workers, technicians and engineers are at work to enable the transformation.

Carrying Isaiah’s “swords into plowshares” vision into the nuclear field did not originate with plutonium. In 1993, the United States and Russia began a 20-year program to take weapons-grade uranium out of the Russian inventory, dilute it to levels appropriate for civilian power plants, and then use it to produce…
Post a Comment
Read more

Missing the Point about Pennsylvania’s Nuclear Plants

By
A group that includes oil and gas companies in Pennsylvania released a study on Monday that argues that twenty years ago, planners underestimated the value of nuclear plants in the electricity market. According to the group, that means the state should now let the plants close.

Huh?

The question confronting the state now isn’t what the companies that owned the reactors at the time of de-regulation got or didn’t get. It’s not a question of whether they were profitable in the '80s, '90s and '00s. It’s about now. Business works by looking at the present and making projections about the future.

Is losing the nuclear plants what’s best for the state going forward?

Pennsylvania needs clean air. It needs jobs. And it needs protection against over-reliance on a single fuel source.


What the reactors need is recognition of all the value they provide. The electricity market is depressed, and if electricity is treated as a simple commodity, with no regard for its benefit to clean air o…
Post a Comment
Read more