Heavy water (D2O) is a coolant as well as a moderator of pressurized heavy water reactors (PHWRs). During operation of PHWRs, deuterium (H-2, D) in heavy water is gradually converted to tritium (H-3, T), which is a radioactive nuclide with a half-life of 12.3 years, by capturing neutron. Various radioactive wastes contaminated by T are generated upon the PHWR operation. Owing to the similarity of D and T, they behave together a form of water (either liquid or vapor) in a normal circumstance. To handle D and T with the water form is quite difficult because it is not a solid and is highly mobile in nature. In this study, a mineralization technique to fix D and T in a solid form is suggested. It is considered that hydroxide minerals, which have low solubility in water, might tightly bind D and T in non-mobile, solid-state media. Feasibility of this strategy is studied by using a copper-based hydroxide mineral, atacamite. Atacamite is a natural mineral found in copper deposits with chemical formula of Cu2Cl(OH)3. Atacamite can be simply synthesized in laboratories by a precipitation method using copper chloride and calcium carbonate as precursors. Both chemicals were added into heavy water to obtain pale-green precipitates. Heavy water is the only source for D in this reaction and thus deuterated mineral is expected to be form. The obtained deuterated mineral, suspected to be Cu2Cl(OD)3, was then immersed in natural deionized water (extremely low D2O concentration) for several days to identify how fast D in Cu2Cl(OD)3 dissolves into water. In a preliminary Fourier transform infrared (FTIR) spectroscopy, absorption peaks related to HDO and D2O were not observed in the deionized water which is recovered after the immersion test, suggesting that D remained stable in the synthesized mineral. However, owing to low detection limit of FTIR, more precise analysis should be taken to clearly identify the stability of D of the deuterated atacamite. If deuterated hydroxide minerals are found to have sufficiently high D stability in natural water, they can be further treated with cement or other stabilization media to form a final wasteform for underground disposal.

최근 미세조류를 에너지원으로 활용하는 기술이 많은 관심을 받으면서 미세조류 고액분리 기술에 대한 연구가 진행 중이다. 미세조류 분리 기술에는 미세조류의 밀도차를 이용하여 분리하는 방법인 원심 분리법, 중력･응집 침전법, 부유선별법과 막 여과법이 있다. 그 중 막 여과법은 다른 공정에 비해 거의 모든 미세조류를 여과 할 뿐만 아니라 가장 간단한 구조로 초기비용이 적게 발생한다는 장점이 있다. 그러나 고밀도의 미세조류는 막오염(fouling)을 야기한다는 단점이 있다. 막 오염(fouling)은 처리수의 투과 수량을 감소시킬 뿐만 아니라 2차 적인 수질오염을 야기시킬 수 있다. 이에 따라 온도가 높은 유입수와 상대적으로 온도가 낮은 처리수의 온도차이로부터 발생하는 증기압 차이를 사용하는 막 증발법을 이용하고자 하였다. 막 증발법은 압력을 구동력으로 사용하는 일반적인 분리막 공정에 비해 온도차를 구동력으로 사용하기 때문에 유입수 중 입자성 물질의 막 표면으로의 물리적인 이송(convection)이 없으므로 막 오염(fouling)이 상대적으로 적게 발생한다는 장점이 있다. 따라서 본 연구에서는 선행연구에서 도출한 공정인자를 이용하여 미세조류를 고액 분리에 따른 투과 성능 및 막 세정 효과를 분석하고자 하였다. 이를 위하여 세정 주기와 세정 방법이 막 회복 및 제거율에 미치는 영향을 살펴보고자 한다.

The quantities of low-grade reject fly ash (RFA) and paper sludge ash (PSA) generated are increasing annually and causing a serious social problem. In this study, the utility of these by-products was analyzed by using RFA and PSA as mineral admixtures. RFA-PSA blended mortar was fabricated and evaluated for use as a cement additive. RFA was milled to improve workability and the hydration reaction, and PSA was mixed with anhydrite to create the ettringite. As the RFA-PSA blended powder replaced 10% of the cement by weight, compressive strength of the mortar exceeded that of ordinary mortar prepared with Portland cement (OPC). Length change (28 days) of the RFA-PSA mortar with a 10% replacement rate was 68% of the OPC mortar and was 62% with a 30% replacement rate.

Samchunpo(Sin Hyang) Harbor is located in the bay of Sa Chun, the central south coast of Korean peninsula. The harbor and coastal boundaries have been protecting by natural coastal islands and shoals. Currently, The Sin Hyang harbor needs maintenance and renovation of the sheltered structures against the weather deterioration and typhoon damages. Consequently to support this, the calculation of accurate design wave through the typhoon wave attack is necessary. In this study, calculation of incident wave condition is simulated using steady state spectrum energy wave model(wide area wave model) from 50 years return wave condition. And this simulation results in wide offshore area were used for the input of the extended mild slope wave model at the narrow coastal area. Finally, the calculation of design wave at Sin Hyang harbor entrance was induced by Boussinesq wave model(detail area wave model) simulation. The numerical model system was able to simulate wave transformations from generation scale to shoreline or harbor impact. We hope these results will be helpful to the engineers doing placement, design, orientation, and evaluation of a wide range of potential solutions in this area.