Update: Hyperion PR explains their reasoning. (h/t Soylent)
Idaho Samizdat reports on nuclear startup Hyperion's recent conference presentation:
[Idaho Samizdat] Hyperion reveals design details of its 25 MW reactor
Dan Yurman calls this the "first release of reactor design information". Except the reactor design "released" appears to have very little to do with Hyperion as it was advertised. Googling into the past:
Hydride fuel
The key to the success of Hyperion will be its fuel – uranium hydride powder, which allows the hydrogen moderator to easily move in and out of the core. The physical characteristics of uranium hydride, a combined fuel and neutron energy moderator, are ideal for the generation of safe nuclear power. The reactor operates at an optimum temperature of 550°C, selected as the goal for the so-called Generation IV reactors by the US Department of Energy (DoE). At 550°C, the dissociation pressure for the hydrogen above the hydride is approximately eight atmospheres, which permits easy transportation of the gas without presenting significant high-pressure risk. The temperature-driven mobility of the hydrogen contained in the hydride can change the moderation, and therefore the reactor criticality, making the reactor self-regulating.
[NEI] High hopes for hydride (January 1 2009) (and many other articles )
Yet what the slides on Samizdat blog describe are not this, but rather a fast reactor, using solid ceramic fuel elements (uranium nitride) with lead-bismuth coolant. This is completely different, and I think it very bizarre that this goes under the same 'Hyperion' name. It is no longer a thermal-spectrum reactor (there is no moderator). The 'unique' idea of the self-regulating uranium hydride fuel is discarded. Sure there are reasons for major redesigns (and this is still purely conceptual), but this isn't even the same idea.
Adding to the strangeness, the Hyperion website quitely erased its original advertisements of hydride fuel. Just look at Google's cache of the main product description. The current version is the same minus one paragraph:
The core of the HPM produces energy via a safe, natural heat-producing process that occurs with the oscillation of hydrogen in uranium hydride. HPMs cannot go “supercritical,” melt down, or get “too hot.” It maintains its safe, operating temperature without the introduction and removal of “cooling rods” – an operation that has the potential for mechanical failure.
Analogous excisions were made on the FAQ page. And as far as the public-facing website goes, there does not seem to be any explanation for (or indication of) this complete reversal.
Incidentally, the new Hyperion seems conceptually similar to the Lawrence Livermore's SSTAR design - like Hyperion, it is a sealed, ~20 MWe, lead-cooled nitride-fuel fast reactor.
Achieving long core life without HEU in a thermal-spectrum reactor is really difficult. You need to be able to refuel the reactor, and their original concept couldn't do it. Their new concept attacks this problem through breeding in a fast spectrum, but then you get new problems, which may in the long run be bigger.
ReplyDeleteThe hydride design didn't get shitcanned:
ReplyDelete"However, in our research of the global market for small, modular nuclear power reactors – aka SMRs – we have found a great need for the technology. Our clients do not want to wait for regulatory systems around the globe, to learn about and be able to approve a uranium hydride system. A true SMR design, that delivers a safe, simple and small source of clean, emission-free, robust and reliable power is needed today – not years from now. As we construct and deploy this launch design, we will continue to work towards licensing Dr. Peterson's design." - http://www.hyperionpowergeneration.com/news.html
Oh, there it is!
ReplyDeleteIn my defense, that explanation was posted TODAY - it wasn't there when I wrote this post last night.
Like everyone else, I was surprised by the change in fuel types. My report on Idaho Samizdat referenced above is based on telephone interviews on 11/16/09 with technical staff at Hyperion and with CEO John Deal.
ReplyDeleteNote also that Hyperion's technical staff told me explicitly that no fuel has been fabricated or tested. I've since been told by an expert in the matter that Los Alamos, which is supplying technical expertise to Hyperion via CRADA, has in fact done work with this fuel type.
See also
R&D work done at UC Berkeley in 2002 and paid for by the US Department of Energy.
The change in the fuel type for Hyperion is based on a decision by the company to go with a fuel type that it believes will have a better chance of passing regulatory review.
At the ANS winter meeting 11/18/09, M. Mayfield of NRC characterized both Hyperion's design and the Toshiba's 4S as "fast reactors." See my additional reporting on small reactors from ANS for comparisons between small LWRs and the two fast reactors.
The Hyperion design is very similar to the Soviet KLT-40S. This 25 MW reactor has been used in Russian subs and ice breakers. The design has a 10-12 year cycle after which the reactor is repalced and the old one decommissioned.
The Hyperion design is very similar to the soviet KLT-40S.
ReplyDeleteReally? I thought it looked a lot closer to the SSTAR. Both ~20 MWe sealed fast reactors, both nitride fuelled, both lead-cooled. But KLT-40S looks like a PWR...
KLT-40S is used in Arkitka class icebreakers. Perhaps you conflated this with the Alfa class of submarines, which use fast reactors?
http://www.fas.org/man/dod-101/sys/ship/row/rus/705.htm
Hyperion's technical leaders recognized after a number of conversations with regulators and other nuclear industry experts that there were too many hurdles between them and uranium hydride as the first step in their plan to build small reactor heat sources.
ReplyDeleteThough uranium hydride has been used for a long time in research reactors, the burn-up experience is not very extensive. There is a lot of uncertainty about the long term performance and durability of the fuel, especially given the chemical changes that enable the moderation to occur.
It is something that may be overcome, but that will take a lot of time and testing. I assume there will also be some design refinements required, which will lead to more required irradiation and verification tests.
As most of you know, the US test facilities for nuclear fuel are about as limited as the world's ability to produce medical isotopes or its ability a couple of years ago to produce very large forgings.
The uranium nitride fuel at least has historic testing and performance records that might be able to be regenerated in sufficient detail to support a license application for a long life core. Without a reasonably long period between refueling, the Hyperion concept of a distributed heat source in off grid applications would be completely uneconomic.
BTW - my discussion above related to Hyperion's fuel choices are mostly conjecture and projection of my own decisions with regard to high temperature reactor fuel and the lengthy test program required. Even with a government head start and head of the line privileges, the HTR test program is not scheduled to complete until about 2016 at which time the detailed NGNP design license will begin. I may be off by a year or so, but the last timeline I remember had operation for NGNP scheduled to start in about 2021. If Hyperion computed anything close to that kind of timeline for uranium hydride verification, I am positive that their venture capital source told them it was a non starter to wait that long before achieving any kind of revenue.
The search for perfection is the enemy of good enough. Good enough is what allows reliable revenue to enable future developments. Just imagine if Intel founders had determined that they would not produce any chips until they could build a Core 2 Duo.
Rod Adams
Publisher, Atomic Insights
The KLT-40S is a PWR. It is the fuel type that is similar at 19/7% enriched uranium.
ReplyDeleteKLT-40S is a reactor widely used in Soviet icebreakers and now proposed for wider use in desalination, on barges, for remote area power supply.
A recent proposal is for a 35 MWe as well as up to 35 MW of heat for desalination or district heating. These are designed to run 3-4 years between refuelling and it is envisaged that they will be operated in pairs to allow for outages (70% capacity factor), with on-board refuelling capability and spent fuel storage.
At the end of a 12-year operating cycle the whole plant is taken to a central facility for overhaul and storage of spent fuel. Two units will be mounted on a 20,000 tonne barge.
The Idaho National Laboratory recently results of HTGR fuel testing. The project involved a three-year test run.
ReplyDeleteRod Adams raises important questions about how, where, and over what time frame Hyperion will fabricate, test, and verify the performance of its latest referenced fuel type for its reactor.