We investigated Ocean sediments and seawater from inside the Fukushima exclusion zone and found radiocesium (134Cs and 137Cs) up to 800 Bq kg-1 as well as 90Sr up to 5.6 Bq kg-1. This is one of the first reports on radiostrontium in sea sediments from the Fukushima exclusion zone. Seawater exhibited contamination levels up to 5.3 Bq kg-1 radiocesium. Tap water from Tokyo from weeks after the ac...

During loss-of-coolant (LOCA) accidents the primary reactor coolant system shall be maintained in a safe state so that the coolability of fuel rods was maintained and the emergency core cooling criteria must be met. These criteria were accepted originally for Western design reactors and the same criteria were applied in Hungary to the Paks NPP as well. However the WER type reactor has different...

Studies of transmutation of long-lived fission products by accelerator and by fission reactor at PNC are described. Four transmutation methods by accelerators are compared in terms of transmutation energy and transmutation rate. A super-powered electron linear accelerator which could transmute a large quantity of fission products has been studied and development of PNC test linac in this line i...

A multi-institutional team led by McDonnell Douglas has undertaken a study which includes the design of both a laser-driven (KrF) and heavy-ion-driven (HI) commercial fusion power reactor. A more general paper describing the overall reactor designs can be found in this proceedings [l]. The cavity, which is the subject of this paper, involves the components surrounding the pellet reaction chambe...

Methanol is recognized as a potential renewable energy source for its uses in gasoline blending and direct methanol fuel cells. This work aims to develop a simulation model that can adequately represent and industrial real-life methanol reactor from a petrochemical plant at steady-state conditions. The main purpose is to provide a tool for investigating the effects of inlet temperatures, coolan...

The MIT Research Reactor (MITR) is evaluating the conversion from highly enriched uranium (HEU) to low enrichment uranium (LEU) fuel. In addition to the fuel element redesign from 15 to 18 plates per element, a reactor power upgraded from 6 MW to 7 MW is proposed in order to maintain the same reactor performance of the HEU core. Previous approaches in analyzing the impact of engineering uncerta...

In reactor calculations, a detailed 3-D power density distribution is required for core optimization studies and safety analyses. The general Monte Carlo based neutral particle transport tool, MCNP [1], has the capability to obtain detailed power density distribution in a reactor through its criticality calculation mode (KCODE mode). However, there is no standard tally type in MCNP that is able...

The Advanced High-Temperature Reactor is a new reactor concept that combines four existing technologies in a new way: (1) coated-particle graphite-matrix nuclear fuels (traditionally used for helium-cooled reactors), (2) Brayton power cycles, (3) passive safety systems and plant designs from liquid-metal-cooled fast reactors, and (4) low-pressure molten-salt coolants with boiling points far abo...