American Nuclear Society Annual Meeting - ANS 2010

The American Nuclear Society (ANS) will hold its 2010 Annual Meeting in San Diego later this month (June 13-17 2010). It will likely be the world's largest conference of nuclear science and technology professionals, and its packed program is breathtaking in the scope, breadth and depth of coverage it provides of the hottest current topics in nuclear science, technology and policy.

I will simply indicate a few of what I consider very interesting sessions and add a comment or two by way of context. As can be expected, most of these are in areas of my research or consulting interest.

First, the Conference will include an Embedded Topical Meeting on the Safety and Management of Nuclear Hydrogen Production, Control and Management - the second such (the first having been held at ANS 2007). Among other interesting papers in this session is one on Probabilistic Safety Analysis of a hydrogen production plant using the Sulphur-Iodine process, with process heat derived from a High Temperature Test Reactor by a Korean group. This directly relates to topics I have discussed in my earlier papers: Safety Issues in Nuclear Hydrogen Production with with the Very High Temperature Reactor and Nuclear Hydrogen Production: Scoping the Safety Issues.

Secondly, the Conference will include a Session on Key Licensing and Regulatory Issues for Small and Medium Reactors, followed by a panel discussion with panelists from INL and the US NRC - I have discussed this topic earlier in other blog posts, and its importance can scarcely be over-emphasized. A group from GE will be discussing the licensing strategy for the PRISM (Power Reactor Innovative Small Module) liquid sodium-cooled reactor, while a group from KAERI (Korean Atomic Energy Research Institute) will discuss the SMART (System-integrated Modular Advanced Reactor) - a water-cooled reactor with integral steam generators that is designed for power (about 100 MWe per module), seawater desalination, and process heat applications. A separate session on Safety Analysis and Licensing of non-LWR Reactor Concepts, should similarly be of strong interest - discussing gas-cooled and liquid-sodium cooled reactors from both an experimental and simulation perspective.

A related session will cover the Thermal Hydraulics of the VHTR (gas-cooled variant), relevant in the context of the licensing of the Next Generation Nuclear Plant. This session will cover ongoing experimental and computational/simulation of VHTR thermalhydraulics at the Oregon State University and INL - particularly on Loss of Flow and Pressurized Conduction Cooldown events in High temperature Reactors. The important issue of scaling - the ability to draw numerical comparisons and conclusions that are valid for real reactors from experiments and simulations done on smaller systems - will be the topic of a paper from Oregon State that should be of particular interest.

The issue of Scaling Methods will also be the topic of a special Tutorial Session, to be conducted by Dr. Pradip Saha of GE and Prof. Jose Reyes of Oregon State - that will discuss issues of scaling particularly with reference to LWRs - methods of dimensional analysis, method of similitude and normalization of governing equations will be discussed.

The topic of Nuclear Fuel and Structural Materials for Next Generation Nuclear Reactors will be the focus of another Embedded Topical Meeting, a topic I have worked on and discussed in several earlier papers and presentations (and blog posts: here, here and here).

I need hardly add that the Conference promises to be extremely interesting indeed!

Safety Issues in Nuclear Hydrogen Production with the (Gas-Cooled) Very High Temperature Reactor (VHTR)

Nuclear Hydrogen Production (NHP) is the idea that the heat and/or electricity from a nuclear reactor can be used to electrolyse, thermolyse, or thermochemically analyse water - separating hydrogen and oxygen. The resulting hydrogen is useful for a variety of markets including hydrocarbon upgrading & refining, ammonia production, and transportation. The merit of the nuclear hydrogen production scheme is that it does not produce greenhouse gases. Alternative hydrogen production schemes currently in use invariably generate carbon dioxide at some stage. The most common technique is methane steam reforming - here carbon dioxide first arises from the burning of methane to produce heat to generate steam, then again in the reforming step that separates the carbon from the methane by successive oxidation to generate hydrogen. Even the alternative electrolysis method that is also common generates carbon dioxide when fossil fuels are burned in the generation of the electricity - whether from gas-fired or coal-fired plants.

While nuclear hydrogen production (NHP) schemes thus are carbon-dioxide emission free, they do involve the use of corrosive fluids (such as sulphuric acid) at high temperatures; generation of noxious & poisonous gases (such as sulphur dioxide and hydrochloric acid); and issues from the possible generation of radioactive products such as tritium. As well, heat transfer fluids carrying heat from the reactor to the thermochemical plant may interact with the chemicals in the plant. Or, in the current conceptual version of the Very High Temperature Reactor, the coolant might be helium, as might also be the heat transfer fluid. Some contamination of tritium in helium is possible and more might arise from transmutation of helium isotopes. In addition, the very idea of having a thermochemical plant located close to a nuclear reactor is unprecedented. Both the hydrogen and the oxygen produced in the thermochemical scheme will need to be safely stored, to prevent the possibility of leakage, deflagration or detonation.

Such considerations impose a number of requirements on the layout of nuclear plants and thermochemical plants, they impose requirements on the amount and quantity hydrogen and oxygen that may be created and stored on site, and on the location of the control room in a nuclear power plant. They also have implications for probabilistic safety analyses (PSA) for combined nuclear-and-thermochemical plants.

The idea of nuclear hydrogen production is especially attractive also in the context of extraction and processing of crude oil from the Alberta Tar Sands. Several reactor-hydrogen production configuration schemes are currently being examined and considered for this project at the present time. Nuclear steam methane reforming (which generates steam from nuclear heat, and uses nuclear heat in the reaction), for example, is a possible transitional technology that decreases the overall carbon footprint of the process (it does not completely eliminate the carbon dioxide production, since it retains the reforming step). For all of these considerations, it is possible that the Tar Sands may emerge as the locus of the first commercial nuclear hydrogen production project anywhere.

I discussed issues surrounding this in my paper Safety Issues in Nuclear Hydrogen Production with the Very High Temperature Reactor (VHTR) presented at the Canadian Nuclear Society Annual Conference 2008, Toronto.