Multipurpose Research Facility Research Articles

Thermo-mechanical behaviour of the MYRRHA core support structure

This work is part of the research on the design of MYRRHA primary system. MYRRHA, a multipurpose research facility, being developed at SCK-CEN, is based on the Accelerator Driven System (ADS) concept. This research facility intends to show the applicability of the ADS principle, and aims to demonstrate, among other objectives, the feasibility of efficient transmutation of high-level nuclear waste. The present study investigates, mainly, the thermo-mechanical behaviour of the core support bundle, fuel assemblies and core devices, in particular, the deformation in terms of the displacement and gaps distribution. To reach this goal, which is arduous, an efficient modeling methodology based on the finite element method has been devised. An effective solution strategy has been formulated to carry out a highly challenging analysis due to severe numerical issues and instabilities, making the solutions particularly difficult to reach for some cases. Analysis cases are differentiated by some friction coefficient values; and the presence or not of a spring pre-compression force. Despite serious convergence issues, converged solutions have been achieved for all the cases studied. From the results analysis, a remarkable feature observed is the stability of the solutions obtained. And, on the whole, the value of the friction coefficient used does not change significantly the displacement, the gaps patterns, and the stresses. Similarly, account of the pre-compression force does not affect much the global behaviour. The kinematic quantities found should be useful for some preliminary reactivity predictions of the reactor.

An updated core design for the multi-purpose irradiation facility MYRRHA

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is a multi-purpose research facility currently being developed at SCK•CEN. It will be able to work in both critical and sub-critical modes and, cooled by lead-bismuth eutectic. It will play a key role in the development of the Pb-alloy technology needed for the lead fast reactor GEN IV concept. MYRRHA will demonstrate the Accelerator Driven System (ADS) full concept by coupling a proton accelerator, a spallation target and a sub-critical reactor at a reasonable power level to allow operation feedback. MYRRHA will also contribute to the study of partitioning and transmutation of high-level waste. Recently, a new core design with a longer active core has been proposed. This paper presents the neutronic analyses for this design improvement. The analyses have been done using the MCNP/X code and the in-house developed ALEPH2 depletion code.

MYRRHA: A multipurpose nuclear research facility

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is a multipurpose research facility currently being developed at SCK•CEN. MYRRHA is based on the ADS (Accelerator Driven System) concept where a proton accelerator, a spallation target and a subcritical reactor are coupled. MYRRHA will demonstrate the ADS full concept by coupling these three components at a reasonable power level to allow operation feedback.As a flexible irradiation facility, the MYRRHA research facility will be able to work in both critical as subcritical modes. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV and fusion reactors, and radioisotope production for medical and industrial applications. MYRRHA will be cooled by lead-bismuth eutectic and will play an important role in the development of the Pb-alloys technology needed for the LFR (Lead Fast Reactor) GEN IV concept. MYRRHA will also contribute to the study of partitioning and transmutation of high-level waste. Transmutation of minor actinides (MA) can be completed in an efficient way in fast neutron spectrum facilities, so both critical reactors and subcritical ADS are potential candidates as dedicated transmutation systems. However critical reactors heavily loaded with fuel containing large amounts of MA pose reactivity control problems, and thus safety problems. A subcritical ADS operates in a flexible and safe manner, even with a core loading containing a high amount of MA leading to a high transmutation rate. In this paper, the most recent developments in the design of the MYRRHA facility are presented.

Gamma dose measurements and spectroscopy analysis for spallation products in JSNS mercury circulation system

Mercury used as a spallation neutron target at JSNS (J-PARC Spallation Neutron Source)� is highly activated by proton beam operation. In order to evaluate the feasibility of hands-on maintenance after nominal beam operation with 1 MW in the where a mercury circulation system was installed, gamma dose measurements and gamma spectroscopy analysis were carried out after low power operation during the commissioning period. By analyzing the data, it was found that radioactive spallation products adhered to the inner surface of piping wall of the circulation systemand those significantly raised the dose rates in the cell. In order to discuss about measures for future hot-cell entry, the gamma dose rates after the nominal operation were evaluated based on the measured data obtained in this work. 1) is a multipurpose research facility with muon and neutron generation target. The operation of the J-PARC spallation neutron source (JSNS) in MLF started in May 2008, and an effort is being made now to increase the proton beam intensity up to 1 MW together with many kinds of researches on materials and life science. 2. Mercury Target and Circulation System. In JSNS, mercury was selected as a material of neutron generation target in consideration of the neutron generation efficiency and the cooling. A drawing of the mercury target vessel and a mercury circulation system on a trolley is shown in Fig 1. Neutrons are generated by bombarding mercury in the target vessel with a proton beam, and the mercury heated by incident protons and accompanying nuclear reactions is circulated in the loop between the target vessel and the mercury circulation system for cooling. The target vessel is inserted to the core of the neutron station consisted of moderators, reflector, neutron beam shutters and shields. For the maintenance, the trolley is moved to the hot cell prepared for handling of activated devices. Mercury in the circulation system is highly activated due to radioactive isotopes produced via spallation reactions. Therefore most of the maintenance works for the mercury target and the circulation system were designed to be done by using remote handling system equipped in the cell. However a few works, which is expected to happen once or twice during the facility lifetime of about 30 years, will need to be done by hands-on; this will necessitate entrance of workers to the cell. Mercury in the circulation system can be transferred to the drain tanks under the circulation system on the bottom of the

Current Status and Performance of the J-PARC Accelerators

J-PARC (Japan Proton Accelerator Research Complex) is a multi-purpose research facility for materials and life sciences, nuclear and particle physics, and nuclear engineering with extremely high power proton beams of 1 MW. The accelerator complex consists of a 400-MeV linac, a 3-GeV Rapid Cycling Synchrotron (RCS), and a 50-GeV Main Ring synchrotron (MR). Its goals are to provide MW-class beams at 3 GeV and at several 10 GeV, while it is a challenge to localize and suppress beam loss to the level to allow hands-on maintenance of accelerator components. The RCS scheme is adopted to realize them, which is advantageous over conventional Accumulation Ring (AR) regarding less beam loss problems due to lower beam current and easier construction and operation of a linac. RCS, however, required various challenging technologies such as ceramic ducts to reduce eddy current effects, high field Radio Frequency (RF) system, and paint injection technique (an injection scheme to reduce phase space density of the beam) to reduce space charge effects. The linac has also unique technologies to minimize beam loss, such as compact electromagnet Drift Tube Quadrupoles (DTQ’s) to control beam envelopes precisely, and a fast beam suspending system in Machine Protection System (MPS) with Radio Frequency Quadrupole linac (RFQ). The beam commissioning of the linac started in Nov. 2006, and its design energy of 181 MeV in the first construction phase was achieved in Jan. 2007. RCS beam commissioning started in Sep. 2007 and the beam was accelerated to the designed energy of 3 GeV in Oct. 2007. MR beam commissioning started in May 2008, and the beam acceleration to 30 GeV was established in Dec. 2008. The first neutron and muon beams were produced in May and Sep. 2008, respectively, at Materials and Life science experimental Facility (MLF). The linac commissioning has resulted in very stable beam with short down time. RCS commissioning quickly achieved beam acceleration and extraction, and paint injections are being studied intensively. RCS recorded the highest beam power of 0.21 MW in Sep. 2008 with beam loss well localized at the collimators. The linac beam energy will be upgraded to 400 MeV with Annular Coupled Structure linac (ACS) in order to increase the beam power to 1 MW. In the second construction phase, upgrade of the linac with 600-MeV Super-Conducting Linac (SCL) for Accelerator-Driven nuclear waste transmutation System (ADS) and upgrade of MR energy from 30 to 50 GeV are planned.Copyright © 2009 by ASME

NASA Glenn Research Center Creek Road Complex—Cryogenic Testing Facilities

Due to expansion at neighboring Cleveland Hopkins Airport, several NASA Glenn Research Center (GRC) facilities have been relocated to the Creek Road Complex. The complex consists of the Small Scale Multi-purpose Research Facility (SMiRF), Cryogenic Components Lab Cell 7 (CCL-7), and a shop building. The facilities have been updated and include state-of-the art technology. SMiRF is a liquid hydrogen/liquid nitrogen (LH 2/LN 2) test facility used to conduct research in a 7400 L vacuum chamber. The chamber simulates space environment and launch vehicle ascent profile. SMiRF handles 5680 L of LH 2. CCL is a LH 2/LN 2 facility to perform small scale proof of concept tests for components and processes. It handles 1130 L of liquid hydrogen. Both facilities handle cryogens at sub-atmospheric pressures.

Technical Editing at the Oak Ridge National Laboratory

Focusing on the crucial role of technical editors and communication managers, the article describes technical editing in environmental and energy research at The Oak Ridge National Laboratory (Oak Ridge, Tennessee). The author examines the kinds of documents prepared, the audiences for whom the documents are intended, and the editing process employed by the Technical Publications Department. The author concludes that communication plays a vital role in complex research and technology and that communicators at The Oak Ridge National Laboratory occupy a central place in the efficient operation of this complex, multipurpose research facility.