[en] Slovakia as one of the world leading countries in the share of nuclear power in electricity production and currently operates 2 nuclear power plants, each with 2 VVER-440 units. In addition to these reactors there are 2 VVER-440 units under construction and 2 units in decommissioning. The VVER-440 technology features thermal neutron spectrum, low enriched uranium dioxide fuel and light-water coolant with diluted boric acid. The reactivity control during normal operation is ensured by the system of emergency reactivity control assemblies (ERC), symmetrically arranged in 37 positions in the reactor core, and by boric acid, homogenously diluted in the moderator. Due to the presence of 10B in the coolant/moderator which has high thermal neutron capture cross-section, the absorption of neutron on these atoms may lead to tritium production. Tritium as the radioactive isotope of hydrogen with half-life of 12.3 years, strongly contributes to the level of radioactivity of the primary coolant, therefore the NPP staff must have appropriate knowledge of its production during operation. The production rate of tritium may be assessed either by experimental measurement or by simulation using state-of-the-art calculation tools. This paper focuses on the estimation of the tritium production for a specific scenario of the operation of the 3rd unit of Mochovce NPP. For simulations the SCALE6 [1] system is used with the detailed calculation model [2] developed at the B&J NUCLEAR ltd. company. The whole-core 3D model of VVER-440 consists of the reactor in-vessel components such as fuel assemblies (including fuel rods, upper spacer grid, intermediate spacer grids, supporting grid, mixing grid, central tube and fuel endings), emergency reactor control assemblies (absorber and fuel part), core basket, barrel and the reactor pressure vessel. The boundaries of the created VVER-440 whole-core model are given by the outer surface of the dry shielding, the level of hot-leg piping and the basement of filtration mechanism. The calculations presented in the paper are performed using self-shielded multi-group cross-section libraries, taking into account the operation conditions of Mochovce unit 3 NPP [3] in the first fuel campaign.(author)

[en] This patent deals with the production of tritium from a lithium compound in a nuclear reactor. Small round particles (30-1000 μm) are composed of a lithium compound (lithium oxide or aluminate), an inside lining in a porous substance (pyrolytic carbide), a gas proof coating made of a dense substance (SiC or 2rC) and a new coat of carbon. The coated particles are irradiated with thermal neutrons in a gas cooled nuclear reactor in order to bring about the transmutation of a preponderant proportion of ⁶Li nuclides to form helium and tritium. The tritium is recovered from the particles by heating them to at least 1300⁰C to bring about diffusion through the external coating. It is also possible to bring these particles to around 1300⁰C in a reactor during a sufficiently long period, for example a week, to ensure the total diffusion of the tritium in the helium atmosphere. The tritium is then eliminated by a recuperation system

[en] Faced with mounting safety problems in its military production reactors, the Energy Department will soon ask Congress to fund the construction of at least one new multibillion dollar tritium production reactor. Energy estimates that building such a reactor could take ten years, and it says that in the interim it needs to continue producing tritium at the Savannah River reactors. In fact, it plans to resume operating its Savannah River reactors at full power as soon as possible. The United States must keep producing tritium if the US-Soviet nuclear arms race continues its present course. If the arms race continues, the Energy Department has two basic options: it could run the Savannah River reactors for several more decades or it could use these reactors until it has built a new one. Operating the Savannah River reactors at full or low power may be risky, even if they undergo extensive safety modifications, since no one knows at what power these reactors can be operated safely. Despite these pressing issues, most of the substantive debate about the role of tritium in nuclear weapons and the requirement for more tritium production is taking place in secret. The public debate largely ignores the broader questions of whether the United States needs to produce tritium and what impact possible agreements reducing nuclear arsenals might have on US tritium requirements

[en] Properties of natural and artificial tritium sources are reviewed and the role of tritium in LWR and PWR is analyzed. (author)

[en] The concept presented here is an adaptation of a recently completed conceptual design of a compact high-fluence D-T neutron source for accelerated end-of-life testing of fusion reactor materials. Although this preliminary assessment serves to illustrate the main features of a linear plasma-based tritium breeder, it is not necessarily an optimized design. We believe that proper design choices for the breeder application will certainly reduce costs, perhaps as much as a factor of two. We also point out that Q (the ratio of fusion power produced to power input to the plasma) increases with system length and that the cost per kg of tritium decreases for longer systems with higher output. In earlier studies of linear two-component plasma systems, Q values as high as three were predicted. At this level of performance and with energy recovery, operating power requirements of the breeder could approach zero. 5 refs., 1 fig., 1 tab

[en] The July 17 rupture of a plutonium separation column at the Chelyabinsk-65 facility of the Mayak chemical production enterprise caused no harm to workers or the local population, and there was no contamination of the territory around the plant, according to an inquiry commission of the Russian state committee for emergencies. Examinations of 17 people in the workshop at the time of the incident have revealed no traces of plutonium in their bodies. Monitoring to a distance of 10 km around the plant found no deviation from previously registered radiation levels. The event has been rated as a level 1 incident on the International Nuclear Even Scale

[en] Slovakia as one of the world leading countries in the share of nuclear power in electricity production and currently operates 2 nuclear power plants, each with 2 VVER-440 units. In addition to these reactors there are 2 VVER-440 units under construction and 2 units in decommissioning. The VVER-440 technology features thermal neutron spectrum, low enriched uranium dioxide fuel and light-water coolant, diluted boric acid and 37 emergency reactivity control assemblies with boron steel absorber. Due to the presence of 10B in the coolant/moderator which has high thermal neutron capture cross-section, the absorption of neutron on these atoms may lead to tritium production. Tritium strongly contributes to the level of radioactivity of the primary coolant, therefore the NPP staff must have appropriate knowledge of its production during operation. This paper focuses on the estimation of the tritium production for a specific scenario of the operation of the 3rd unit of Mochovce NPP. For simulations the SCALE6 system is used with the detailed calculation model developed at the B&J NUCLEAR ltd. company. The calculations presented in the paper are performed using self-shielded multi-group cross-section libraries, taking into account the operation conditions of Mochovce unit 3 NPP in the first fuel campaign. (author)

No abstract available

[en] The purpose of this paper is to examine the essential features of tritium breeding blankets employing helium-3 as the breeding medium. The concept exhibits good tritium breeding potential, attractive safety features, and relatively low development risk. Both near-term and commercial applications are considered. The near-term application is based on using terrestial sources of helium-3, while the commercial application is based on an extra-terrestrial helium-3 source, perhaps the lunar surface. If these helium-3 sources can be realized at costs in the range of -- 100-500 $/g then helium-3 offers an attractive alternative to lithium as a tritium breeding medium for fusion applications

[en] In late 1995, DOE is schedule to announce a new tritium production unit. Near the end of the last NPR (New Production Reactors) program, work was directed towards eliminating risks in current designs and reducing effects of accidents. In the Heavy Water Reactor Program at Savannah River, the coolant was changed from heavy to light water. An alternative, passively safe concept uses a heavy-water-filled, zircaloy reactor calandria near the bottom of a swimming pool; the calandria is supported on a light-water-coolant inlet plenum and has upflow through assemblies in the calandria tubes. The reactor concept eliminates or reduces significantly most design basis and severe accidents that plague other deigns. The proven, current SRS tritium cycle remains intact; production within the US of medical isotopes such as Mo-99 would also be possible