Mankind now enjoys many benefits from nuclear-related technologies. There is, however, growing concern in many OECD countries that nuclear education and training is decreasing, perhaps to problematic levels. This report conveys the results of a pioneering survey on nuclear education and training in almost 2000 organizations in 16 countries. In most countries there are now fewer comprehensive, high-quality nuclear technology programs at universities than before. Facilities and faculties for nuclear education are aging, and the number of nuclear programs is declining. The principal reason for the deterioration of nuclear education is the downward spiral of budgetary cut and low enrolment of student whose perception is affected by the educational circumstances, negative public perception, the downsizing of the industry, and reductions in government-funded nuclear programmes, where little strategic planning is occurring. Unless something is done to arrest it, this downward spiral of declining student interest and academic opportunities will continue. Failure to take appropriate steps now will seriously jeopardize the provision of adequate expertise tomorrow. We must act now on the following recommendations: strategic role of governments; the challenges of revitalizing nuclear education by university; vigorous research and maintaining high-quality training; and benefits of collaboration and sharing best practices.

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As for the design of the compact heat exchanger (recuperator) of HTGR-GT system by the helium gas turbine, heat exchanger effectiveness (HEE) is set to the goal in 92% of very high values. A recuperator is consisted of multi-layer core element with the combination of ultra fine offset fins (fin height×pitch×offset×thickness, 1.1-1.5mm×1.1-1.5mm×3mm×0.15mm), separator, header with ultra fine straight fins (fin height×pitch×thickness, 1.1-1.5mm×3mm×0.15mm)and ducts. By the concept design of this recuperator, it got the prospect that 95% of HEE can be achieved by making this ultra-fine offset fin-type core element with the flow channel width×height×length, 890mm×6, 800mm×940mm. However, there is possibility that the flow unbalance occurs to the cold flow, which is supplied to the direction of the core element height from the header when the recuperator size becomes large-sized in this way and as results, that the performance of the recuperator declines. Therefore, by implementing the three-dimensional heat transfer flow analysis of the recuperator, it evaluated a performance about the heat transfer of the recuperator when the virtual flow unbalance occurs to the direction of the height of the duct of the side of cold flow.
As a result, the following conclusion was derived;
(1) Helium flow unbalance in the cold flow header is caused by the maximum, -20% to 14% to all the helium flow rate.
(2) When the flow unbalance which is identical with cold flow along the header occurs on the hot flow header, it declines by about 0.5% to HEE per recuperator 1 unit when the flow unbalance does not occur on the cold flow.
(3) When the symmetrical flow unbalance in cold flow header occur on the hot flow header, the rate with the declining heat transfer performance of the recuperator is the biggest. It declines by about 1.3% to the HEE per recuperator 1 unit when the flow unbalance does not occur on the cold flow header of the case.
When above result, the assumed flow unbalance occurred, the thing about which it is possible to design the recuperator which meets a design request specification was concluded.

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The Japan Atomic Energy Research Institute is developing a several MW-scale spallation target system under the High-Intensity Accelerator Project. A cold moderator using supercritical hydrogen is one of the key components in the target system, which directly affects the neutronic performance both in intensity and resolution. Since a hydrogen temperature rise in the moderator vessel affects the neutronic performance, it is necessary to suppress the recirculation and stagnant flows which cause hot spots. In order to develop the conceptual design of the moderator structure in progress, the flow field was measured using a PIV (Particle Image Velocimetry) system under water flow conditions using a flat model that simulated a moderator vessel. From these results, the flow field such as recirculation flows, stagnant flows etc. was clarified. The hydraulic analytical results using the standard k-ε model agreed well with experimental results. Thermal-hydraulic analyses in the moderator vessel were carried out under liquid hydrogen conditions. Based on these results, we clarified the possibility of suppressing the local temperature rise within 3K under 2MW operating condition.

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Fracture behavior of nuclear grade graphites was investigated under tensile-compressive stress distribution or stress gradient in front of inherent flaws in graphite materials, using the tension-bending bimodal strength test machine.
Tensile, three and four point bending tests and fracture toughness test were carried out with notched specimens (width×thickness×gage length=20mm×10mm×60mm, notch length=0-5.2mm) made of fine grade isotropic graphite, IG-110 and coarse grained quasi-isotropic graphite, PGX, and the following conclusions were derived;
(1) The following relationship between notch length, a and fracture strength, σf was well expressed as;
σ_f=Aa^-1/2,
where A: constant.
(2) Fracture toughness estimated by ASTM standard decreases as ligament ratio, a/W decrease in the range of a/W<0.05.
(3) The highest fracture resistivity was observed in 3 point bending test and the lowest one was in tensile test.
(4) Fracture toughness defined by on-set point of fracture can be evaluated in unique in these strength tests.

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