We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products--(131,132)I, (132)Te, and (134,137)Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

We measured in situ the radiation-induced absorption of pure silica core fibers exposed to a fission nuclear reactor. We observed the growth of the 1.39m OH vibration band in polymer coated fiber. Three mechanisms are responsible for this effect: recoil protons, hydrogen diffusion, and a probable compaction effect. Based on this experiment, a fiber-optic neutron monitor prototype is proposed.

Although there have been some severe nuclear accidents such as Three Mile Island (USA), Chernobyl (Ukraine) and Fukushima (Japan), nuclear fission energy is still a source of clean energy that can substitute for fossil fuels in a centralized way and in a great amount with commercial availability and economic competitiveness. Since the pressurized water reactor (PWR) is the most widely used nucl...

} The mechanistic smeared cracking model was extended from two to three dimensions (page 2). } Subcontinuum molecular dynamics simulations were used to investigate oxide fuel grain boundary fractures during reactor transients (page 2). } An improved model of bubble and grain boundary interaction was developed (page 2). } Improved descriptions of fission-gas/grain boundary interactions and clust...

Abstract Corrosion products in the primary circuit of Pressurized Water Reactor (PWR) during operation will cause Chalk Rivers Unidentified Deposit (CRUD), increase level coolant source term and deposition outside core, then affect normal PWR radiation field shutdown overhaul. Stretch-Out (SO) is a flexible mode reactor, which can improve economy reactor. In this paper, theoretical model CRUD a...

The Vienna TRIGA Mark II reactor was modelled by means of the Serpent-2 Monte Carlo burnup calculation code. The purpose of the modelling is the determination of core critical parameters and of nuclear fuel composition time evolution. This paper presents the Serpent-2 reactor model validation process carried out during the last year. Taking into account the irradiation history, the fuel composi...