For the decommissioning or continuous long-term power generation of nuclear power plants, it is necessary to transfer the spent nuclear fuel from the wet storage pool to the dry storage. Spent nuclear fuel should go through the drying process, which is the first step of dry storage. The most important part in the drying process is the removal of the residual water. The spent fuel might be stored in a dry storage system for a long time. The integrity of internal components and spent fuel cladding should be maintained during the storage period. If residual water is present, problems such as aging of metal materials, oxidation of cladding, and the hydride-reorientation could occur. The presence or absence of residual water after vacuum drying is evaluated by pressure. If there is residual water in the vacuum drying process, it evaporates easily at low pressure to form water vapor pressure and the internal pressure rises. In the recent EPRI High burn up demonstration test, the gas inside the canister that satisfied the dryness criteria was extracted and analyzed. It showed that the water content was higher than the expected value. We are conducting verification studies on the pressure evaluation method, which is an indirect evaluation method of vacuum drying. The vacuum drying test was performed on small specimens at Sandia National Laboratory, and quantitative residual water evaluation was also performed. The report did not mention a detailed method for the assessment of residual water. Based on the test results of SNL, direct residual water evaluation was performed using energy balance. If the dryness criteria were satisfied, the quantitative amount of residual water was also evaluated. As a result, almost the same result as the evaluation result of SNL was derived, and it was confirmed that most of the water was removed when the dryness criteria was satisfied.

보수성 포장재가 지표면 열수지와 중규모 순환장에 미치는 영향을 파악하기 위하여 수치실험과 야외 관측을 실시하였다. 수치실험에 이용된 모형은 LCM(Local Circulation Model)이며, 야외 관측은 대기가 안정되어 날씨가 맑은 2007년 7월 19일 실시되었다. 야외 관측실험에서 보수성 포장재 지표면 온도의 최대치는 1430 LST에서 41.2˚C이고, 보수성 재료가 도포되어 있지 않은 일반 아스팔트보다 16.1˚C 낮게 관측되었다. 수치실험에서는 증발효율 0.3을 가정한 case BET03에서 관측과 가장 유사한 값을 나타내었다. 이때 현열과 잠열플럭스는 각각 227 와 229 W/m2이다. 수치실험 결과, 보수성 포장재는 낮은 지표면 온도, 혼합고와 관련된 잠열플럭스를 높이는 경향이 나타난다. 보수성 포장재에 의한 잠열플럭스의 불연속은 교외풍과 같은 중규모 순환장의 발달을 강화시키는 역할을 한다.

In construction sites there are many cases that concrete is cured in a dry condition, without being moistured, after form have been removed. Consequently such curing condition causes cracks on concrete. In this study is to observe when applied ERCO(Emulsified Refined Cooking Oil) coating on concrete surfaces after removal of form, affects water evaporation and Shrinkage of high-strength mortar.

LFG, generated by the decomposition of wastes, is very humid and has high temperature. When it cools during its transfer in the piping system, condensate forms, blocking the flow of LFG. Typical condensate removal devices, which works on the principle of trap usually used in the sewer pipe and utilizes water to prevent the intrusion of outer gas and to drain condensate, have limitation for their uses in landfill by the evaporation of water when it comes to dry condition in the landfill. In this study we investigated the temperature distribution in the waste layer and the possibility of the evaporation of water in the trap. LFG could be cooled down or heated by the temperature of waste layers where the transfer pipe locates. Evaporation rates, estimated by the use of temperature distribution in the landfill, were high enough to cause malfunctions when the difference of temperature between LFG and waste layer is high.