Drop tests of TUK-84 for accident conditions during shipment

Tests for mechanical damage of the TUK-84 shipment assembly, used for shipping and dry storage of spent nuclear fuel, with the container drop from a height of 9 m on a rigid base and from a height of 1 m on a steel pin are described. The basic data from the measurements of the impact parameters are presented, the results of tests for defects and post-test checking are presented, and results of acceptance tests for mechanical damage are also presented. __________ Translated from Atomnaya énergiya, Vol. 100, No. 6, pp. 445–448, June, 2006.     

Methods and results of tests of a large model of the TUK-84 container

Tests of a prototype model of TUK-84 and the corresponding experimental procedures used at the test center of the All-Russia Research Institute of Technical Physics are described. The results are presented, and it is shown that the prototype withstood the tests. __________ Translated from Atomnaya énergiya, Vol. 100, No. 6, pp. 441–445, June, 2006.     

Construction of the TUK-84 shipping assembly

The construction and basic technical characteristics of the TUK-84 assembly are described. The materials used to fabricate the vessel parts and sealing components are presented, and the composition and operation of the system which monitors the technical parameters are described. The construction of the rolled layers (courses) is discussed and their advantages are shown. __________ Translated from Atomnaya énergiya,Vol. 100, No. 6, pp. 419–422, June, 2006.     

Computational estimate of the dynamical response of TUK-84 in tests under accident conditions during shipment

A computational finite-element model of TUK-84 is described. The expected results are presented for the parameters of the first five impacts on TUK-84 when it is dropped from a height of 9 m and data from calculations of the dynamical stress-strain state of the structure which correspond to the maximum stresses and strains in the vessel and cover under a prescribed action. The computational model of the container is described for the case where the container is dropped from a height onto a pin, and the boundary conditions and expected maximum flexing in the impact zone are shown. __________ Translated from Atomnaya énergiya, Vol. 100, No. 6, pp. 437–440, June, 2006.     

Design and performance tests of an efficient sample preparation system for AMS-14C dating

To achieve effective sample preparation for AMS-¹⁴C dating, an improvement on automated AAA treatment system has been carried out. The new method is in particular useful for the preparation of charred materials on potsherds on which we are mainly focused. An additional carbon extraction and graphitization system with elemental analyzer was also introduced in National Museum of Japanese History. These systems work properly with little memory effect and sufficient blank level.     

Strain analysis on ductile cast iron containers at drop tests

Ductile cast iron (DCI) containers for transportation and deposition of radioactive waste have to be designed carefully in order to avoid unacceptable damages and leakages in case of an accident. Therefore various calculations and experimental methods are used during development and licensing of the containers. Besides others the container has to suffer severe impacts (e.g. falling from a height of several meters onto a concrete base). The level of strains must not exceed a value which would adversely affect the package in such a way that it would fail to meet the applicable requirements. In practice complex events such as drop tests are very difficult to calculate. Both the position of maximum stress and the time of its occurrence are not easily predicted with the method of FEM. The uncertainty of the material modelling for plastic deformation by dynamic loading rates is the limiting factor. Therefore holography as an integral measuring technique in combination with strain gauge techniques were used to fit the FEM. By using the FEM calculations in the case of licensing, the FE and the material model have to be verified. The verification of the FE model has to be done by comparison of the local maxima measured by strain gauges and by comparison of the vibration modes. These vibration modes we take from holographic measurements. In this paper we explain container vibrations after impact analysed with holographic measurements, FEM calculations and the comparison of the results. The comparison of the local maxima (strain gauges/FEM) is reported elsewhere (Schreiber, D. et al., 1993. Trans. 12th Int. Conf. J04, 5, pp. 101–108; Völzer, W. et al., 1997. Technical Semin. on Brittle Fracture. Krefeld 27–28.10.94, RAMTRANS (in press)).     

Demonstrative drop tests of transport and storage full-scale canisters with high corrosion-resistant material

The concrete modular dry storage technologies are becoming widely used, aiming at better economic performances. With longer perspective, there are still key issues related to safety standards in operation and maintenance during storage and unloading/loading for transportation, long-term integrity of the storage components. On the other hands, due to the lack of the experimental studies related to tipping-over or drop event scenarios, it is very important to evaluate the characteristics of the behavior of the components, such as the multi-purpose canister (MPC) subjected to impact loads. Therefore, we executed the demonstration drop test program using double-lid welded MPCs, with the aim of obtaining basic data for regulating safety. This paper introduces the summary of our drop test program.     

Topical BAM cask design evaluation using drop tests and numerical calculations: accidental cask drop without impact limiters onto storage building foundation

Abstract

Cask impacts without impact limiters onto unyielding targets result in totally different mechanical reactions from those of relatively smooth impacts using impact limiters. During the licensing procedure of the new GNS CASTOR HAW 28M design for vitrified high activity waste, BAM therefore decided to perform an additional drop test with a 1 : 2 scale test cask (CASTOR HAW/TB2). In spite of a small drop height of only 0˙3 m onto the unyielding target of the BAM drop test facility, which conservatively covers any storage building foundation, the impact caused considerable stresses to the cask structure with high stress and strain rates. This paper presents the evaluation strategy of BAM including the drop test results and the development and qualification of appropriate finite element modelling to achieve sufficient agreement between test and calculation results. Further steps include mechanical analyses of reduced and full scale cask designs to determine the most critically stressed areas of the structure, verify scaling factors and demonstrate safety with respect to cask integrity and tightness.     

New cold nuclear fusion theory and experimental tests

A theory of neutron-induced tritium-deuterium fusion at room temperature is developed, based entirely on previously measured cross-sections of known nuclear reactions. The fusion process involves self-sustaining chain reactions: (1)n+⁶Li ⁴He+T and/orn+⁷Li⁴He+T+n, and (2) T+D ⁴He+n, in Li-D plasma or pellet surrounded by Li and other blankets and by neutron reflectors. The recent results of cold deuterium fusion reported by Fleischmann, Pons, and Hawkins are described in terms of this fusion process. Experimental evidence and tests of the chain reaction hypothesis are described.     

Development of new sub-miniature fission chambers: Modelling and experimental tests

The LSMN (Nuclear Measurement Systems Laboratory) of CEA/Cadarache designed and manufactured a new generation of sub-miniature fission chambers (SMFC). An experiment with three SMFCs was carried out in 2001 in the BR2 research reactor within the framework of a collaboration agreement with SCK·CEN Mol.

In this paper we present the experimental results for the neutron sensitivity, the gamma effect, the current/voltage characteristics and the long term behaviour up to a fluence of 2.10²¹ n/cm². We also compare the data with results from calculations with our FCD computer code. The onset of the saturation domain is well predicted by FCD; for the neutron sensitivities FCD yields the correct orders of magnitude but the underlying model should still be refined.     

Analysis of EXCOBULLE two-phase expansion tests

A model based on equilibrium thermodynamics was developed to analyse the EXCOBULLE experiments. Large rates of heat and mass transfer are required to obtain agreement with the experiments. The early heat and mass transfer is due to Taylor instabilities followed by condensation and bulk mixing of hot fluid and cold water; later heat transfer occurs across a stable bubble surface by condensation, calculated from kinetic theory. Eventually heat transfer is controlled by conduction in the surrounding water, but conduction-limited heat transfer in the early part of the transient is too slow to account for the experimental results. The mechanical work done by the expanding bubble is reduced significantly by the heat and mass transfer.     

An experimental validation of the guideline for inelastic design analysis through structural model tests

In this paper, the inelastic analysis procedures recommended to use in the advanced elevated temperature structural design guide under development in Japan for the improved design of future fast breeder reactors were validated through the structural model tests and the evaluation of the experimental results by the inelastic analyses. First, a thermal fatigue test of a 316FR hollow cylinder with two longitudinal weldments was conducted under the condition of combined constant axial load and cyclic movement of axial temperature distribution, which simulated the loading condition near the free surface of coolant sodium in the main vessel of fast breeder reactors (FBRs). In the experiments, longitudinal and radial ratcheting deformation were measured and crack initiation life was also examined. Second, the inelastic analyses were carried out in accordance with the recommended procedure by using the measured results of oscillating temperature distribution. Finally, the results of inelastic analyses were compared with the experimental results and it was validated that the recommended practice gave a conservative result for the deformation and a good estimation of strain range for the fatigue life evaluation.     

一种实验炼钢渣的穆斯堡尔谱研究

一种实验炼钢渣不同炉次样品的室温透射穆斯堡尔谱由两组裂距较大的四极分裂双峰和一组裂距较小的双峰组成，它们分别相应于具有不同微观环境的Ｆｅ＾２＋和Ｆｅ＾３＋。参照文献中已知ＦｅｘＯ的穆斯堡尔谱数据，可确定该渣中的主要含铁相为ＦｅｘＯ。Ｘ射线衍射相分析给出相同的结果。按亚谱的面积比计算出Ｆｅ＾２＋和Ｆｅ＾３＋的相对含量分别为８５％和１５％左右。进一步选取与样品晶体结构相联系的原子簇模型。用ＭＳ－Ｘａ方     

Analysis of pressure vessel steel fatigue tests in air

Fatigue data on A533B and A508 steels tested in air at laboratories all over the world are analyzed by the FATigue Data Analysis Code, FATDAC. A model including an R-ratio factor is fitted to the data, and the quality of the fit is verified by several sets of data that were not used for fitting.     

An experimental study on pressure drop and dryout heat flux of two-phase flow in packed beds of multi-sized and irregular particles

This paper is concerned with debris bed coolability in a postulated severe accident of light water reactors, where the debris particles are irregular and multi-sized. To obtain and verify the friction laws predicting the hydrodynamics of the debris beds, the drag characteristics of air/water single- and two-phase flow in a particulate bed packed with multi-sized spheres or irregular sand particles were investigated on the POMECO-FL test facility. The same types of particles were then loaded in the test section of the POMECO-HT facility to obtain the dryout heat fluxes of the particulate beds heated volumetrically. The effective (mean) particle diameter is 2.25 mm for the multi-sized spheres and 1.75 mm for the sand particles, determined from the Ergun equation and the measured pressure drop of single-phase flow through the packed bed. Given the effective particle diameter, both the pressure drop and the dryout heat flux of two-phase flow through the bed can be predicted by the Reed model. The experiment also shows that the bottom injection of coolant improves the dryout heat flux significantly and the first dryout position is moving upward with increasing bottom injection flowrate. Compared with top-flooding case, the dryout heat flux of the bed can be doubled if the superficial velocity of coolant injection is 0.21–0.27 mm/s. The experimental data provides insights for interpretation of debris bed coolability (how to deal with the multi-sized irregular particles), as well as high-quality data for validation of the coolability analysis models and codes.     

采用BETHSY自然循环实验数据对CATHARE2 V1.5qR6程序的评价

采用BETHSY自然循环实验数据对CATHARE2 V1.5qR6进行了评价.结果表明CATHRE2V1.5程序能较好地预测试验装置单相自然循环条件下的热工水力现象,对单相自然循环向两相自然循环的转变以及两相自然循环向回流冷凝运行方式的转变发生时的一回路水装量预测也比较准确,但对于两相自然循环及回流冷凝运行方式下系统的一些主要热工水力参数预测欠佳.评价结果表明,与许多国际性大型热工水力分析程序一样,CATHARE2V1.5qR6程序对剧烈两相流动的预测能力仍有待改进和完善.     

Temperature evaluation of an instrumented capsule after material irradiation tests in HANARO

An instrumented capsule has been used for an irradiation test of various nuclear materials in the research reactor, HANARO. The capsule is designed to have a standard 4-hole structure for the economical test of an RPV material at 290 ± 10 °C. The temperature of the specimens for the reactor powers, 0-24 MW, is measured by 12 thermocouples, and finite element (FE) analyses are also performed to compare and verify the irradiation test results. As a result of the tests and analyses, the maximum temperature at the reactor power of 24 MW is 256 °C for an irradiation test and 202.6 °C for an FE analysis at Stage 3 of the capsule. Also, for each stage of the capsule, the temperature difference of the specimen in the axial direction is very small to within 10 °C. It is expected that the results presented in this paper will be useful when designing the instrumented capsules for an irradiation test.     

Single event upset tests of an 80-Mb/s optical receiver

This paper studies the single event upset (SEU) sensitivity of a radiation-tolerant 80-Mb/s receiver developed for the CMS Tracker digital optical link. Bit error rate (BER) measurements were made while irradiating the receiver with protons and neutrons at different beam energies and incident angles and for a wide range of optical power levels in the link. Monte Carlo simulations have also been used to assist in the interpretation of the experimental results. As expected, the photodiode is the most sensitive element to SEU. The fake signal induced by direct ionization dominates the bit-error cross-section only for protons incident on the photodiode at large angles and low levels of optical power. Comparison of the neutron and proton bit-error cross-sections demonstrates that nuclear interactions contribute significantly to the proton-induced SEU errors and that they will dominate the radiation-induced error rate in the real Tracker application