[Cyber Liberty]

That’s what I thought.

We really need to get into that technology. It’s safer, and there’s no need to shut down and recalibrate the reactor for refueling. Just dump used pellets from the bottom and add new ones at the top.

Germany’s doing it, right?

[ASOC]

China is building a commercial PBR (they have a tiny 4MW unit to learn from now operating)

One is underway in South Africa (odd, that) and others are planned.

The problem has always been the precision need for the ‘pebbles’ The Germans had a Duce of a time getting any kind of decent yield...and I believe gave up due to costs.

The Toshiba model 4S (proposed for Alaska (Galena)is interesting for a sodium cooled unit — and an even smaller unit (200KW) - at 6 feet wide and 20 feet long — it is designed to run unattended. Yup - doesn't even need Homer.

One of these will be on line in Japan this year, with Europe getting some in 2009.

[rednesss]

The AP1000 design is very, very safe. There are drawbacks to the PBR design, it’s not all sweetness and light. The AP1000 design has been approved by the NRC and if we were smart, we’d Henry Ford these production line style and pump out hundreds. By doing so, the time to get these sites approved and the cost of construction would go down.

[sefarkas]

The problem is as much regulatory as anything. The South Africans took a German technology and perfected it.

Bringing that technology to America will require the Nuclear Regulatory Commission to develop a method/regulations by which to evaluate an application for a license to use the technology. Many aspects of the current licensing process assume licensees wanting to construct Pressurized Water Reactors (e.g., Westinghouse AP1000 and earlier models) or Boiling Water Reactors (all the flavors created by General Electric), and a few other also rans. As a result, the NRC has a large staff of scientists and engineers with expertise in PWRs and BWRs constrained by the NRC’s administrative procedures.

The NRC does not have a staff waiting around for a pebble-bed reactor application, nor any other reactor technology for that matter. Note that the Canadian design was the original objective of the Dominion application that later turned to the BWR on this very issue. The CANDU is a proven design and relatively close to the PWR concept. Even a close cousin like the CANDU was too different for the NRC to manage. The NRC is already quite busy with the pre-licensing work associated with the approximately 30 applications on board or on their way.

As a result, their is no chance that a pebble bed plant will be built in the US any time soon. Furthermore, since most other Western nations adopt NRC regulations, policies, and procedures, it is unlikely that any other country would license the use of the pebble bed outside of South Africa and China.

This is why the repeated postings I see requesting/chiding/belaboring the pebble bed issue in the context of having such plants in America serve only to distract/dilute support of nuclear power that has grown up in this country since the lull of 1997. American utilities have many fine already approved designs to choose from for their next nuclear project. The talk of pebble bed on FR is at best an academic exercise left to folks in the commercial nuclear business.

To me, demanding a pebble bed reactor in this country is no different from demanding that Yucca Mountain (or similar) be built before moving forward with the next generation of nuclear plants that are now available to American utility companies.

[cowboyway]

We really need to get into that technology. It’s safer, and there’s no need to shut down and recalibrate the reactor for refueling. Just dump used pellets from the bottom and add new ones at the top.

Pebble beds are much smaller, are helium cooled and graphite moderated. (Chernobyl was graphite moderated and was continuously refueled.)

The Pebble Bed Modular Reactors (PBMR's) have some selling points such as less piping for coolant (there will still be plenty of piping for steam production), don't need to shut down for refueling and they can be 'manufactured' versus on site construction.

But graphite is highly flammable and will add to the radwaste problem. Also, if the helium coolant is released the PBMR's rely on air as the backup coolant and that's the reason why there isn't a containment building.

But, like Carl Sagan said, there is no free lunch. Regardless of the design, we're still dealing with fissionable, highly radioactive materials, high pressure and temperatures that will fatigue any material over time and will require maintenance.