In order to improve the cryopreservation by vitrification or slow freezing of nuclear transplant rabbit embryos, the effects of factors affecting embryo cryopreservation such as cryoprotectants, equilibration, cooling rate and post-thaw dilution on post-thaw survial and development were determined using intact embryos of morular stage. And the post-thaw development of nuclear transplanted embryos cryopreserved under the optimal conditions examined was compared between vitrification and slow freezing. The cryoprotectant solution used was ethyleneglycol-ficoll-sucrose (EFS) or ethyleneglycol-poly-vinylpyrrolidone-galactose- I (EPG- I ) for vitrification, and EPG- II for slow freezing. To examine the viability of frozen-thawed embryos, the nuclear transplanted embryos were co-cultured in TCM-199 plus 10% FBS with bovine oviduct epithelial cells(BOEC) for 24 hrs and the intact morulae were co-cultured with BOEC for 5 days and 3 days to hatching blastocyst stage in 39 ˚C 5% incubator. The results obtained were as follows: Following vitrification with EFS, the post-thaw development of rabbit morulae to hatching blastocyst was significantly(P<0.05) higher in compacted stage(82.4%) than in early morular stage(60.0%). The post-thaw development of compacted morulae to hatching blastocyst was similarly high in vitrification with EFS(82.4%), EPG- I (85.0%) and in slow freezing with EPG- II (83.3%). Following vitrification with EPG- I, the post-thaw development of intact rabbit morulae to hatching blastocyst was similar as 78.0% and 85.0% in 1-step and 2-step post-thaw dilution, respectively. The post-thaw development of nuclear transplanted rabbit embryos of compacted morulae stage to hatching blastocyst was similarly 43.6% and 40.0% in vitrification with EPG- Iand slow freezing with EPG- II, respectively. These results indicated that the rabbit nuclear transplant and intact embryos of morulae stage could be well cryopreserved with either vitrification or slow freezing procedure.

The influence of cryopreservation of donor embryos on the in vitro developmental potential in the nuclear transplant rabbit embryos was evaluated. The embryos of 16-cell stage were collected and cryopreserved with EFS solution by vitrification method. The frozen embryos were thawed and synchronized to S and G phase of 32-cell stage. The recipient/ cytoplasms were obtained by removing the first polar body and chromosome mass from the oocytes collected by non-disruptive microsurgery procedure. The separated S and G phase blastomeres of 32-cell stage were injected into enucleated recipient cytoplasms by micromanipulation. After culture until 20 hrs post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. The fused nuclear transplant embryos were co-cultured with rabbit oviduct epithelial cells. After in vitro culture for 120 hrs, the nuclear transplant embryos developed to blastocyst stage were stained with Hoechst 33342 dye and their blastomeres were counted. The electrofusion rate was significantly (P<0.05) reduced in the frozen nuclear donor,compared with fresh donor nuclei as 80.0 vs 62.8% in S phase and 81.7 vs 64.8% in Gphase, respectivley. The in vitro developmental rate to blastocyst stage with the S and Gphase of fresh embryos(26.3 and 61.1%, respectively) was found significantly (P<0.05) higher, compared to the S and G]phase of frozen embryos(11.9 and 34.6%, respectively). When frozen as well as fresh donor embryos were synchronized to G phase, the in vitro developmental rate to blastocyst stage was significantly (P<0.05) higher, compared with S phase donor nuclei. The cell counts of nuclear transplant embryos developed to blastosyst stage were significantly (P<0.05) more in G phase of fresh or frozen embryos (180.1 and 125.7 cells, respectively), compared with S phase nuclear donor (145.1 and 103.7 cells, respectively). From the above results it was concluded that the rabbit embryos cryo- preserved by vitrification might be available as nuclear donor, though the developmentalpotential and cell counts of nuclear transplant rabbit embryos were decreased significantly.

The present study was conducted to investigate the influence of embryo cell stage at 18h post-fusion and oocyte preactivation on sebsequent in vitro developmental potential in the nuclear transplant rabbit embryos. The embryos of 16-cell stage were collected and synchronized to G phase of 32-cell stage. The recipient cytoplasms were obtained by removing the first polar body and chromosome rnass from the oocytes collected by non-dis-ruptive microsurgery procedure. The separated G phase blastomeres of 32-cell stage were injected into non-preactivated recipient cytoplasms. Otherwise, the enucleated recipient cytoplasms were preactivated by electrical stimulation at 18h post-hCG injection and the separated G phase blastomeres of 32-cell stage were injected. Mter culture until 20h post-hOG injection, the nuclear transplant oocytes were electrofused by electrical stimulation. The fused nuclear transplant embryos were classified into 3~4-cell, 2-cell and 1-cell stage at 18 hrs post-fusion and cultured until the embryos reached blastocyst stage. The developmental rate to blastocyst stage was significantly (P <0.05) higher in all the reconstituted embryos of 3~4-cell stage(58.0%) than in 2 and icell stage. The developmental rate to blastocyst stage in the embryos of 3~4-cell stage at 18 hrs post-fusion was significantly (P<0.05) higher in the reconstituted without oocyte preactivation(77.8%) than in the oocyte-preactivated embryos (33.3%). These results indicated that the higher rate of in the in vitro development to blastocyst stage might be obtained form the embryos which were reconstituted with nuclear donor of G phase and non-preactivated oocyte, and developed more rapidly for 18 hrs post-fusion.

This study evaluated the influence of cell stage of donor nucleus on nuclear injection, electrofusion and in vitro development in the rabbit to improve the efficiency of nuclear transplantation in the rabbit. The embryos of 8-, 16- and 32-cell stage were collected from the mated does by flushing viducts with Dulbecco's phosphate buffered saline(D-PBS) containing 10% fetal calf serum(FGS) at 44, 54 and 60 hours after hCG injection. The blastorneres separated from these embryos were used as donor nucleus. The ovulated oocytes collected at 14 hours after hCG injection were used as recipient cytoplasm following removing the nucleus and the first polar body. The separated blastomeres were injected into the enucleated oocytes by micromanipulation and were electrofused in 0.28 M mannitol solution at 1.5 kV /cm, 60 sec for three times. The fused oocytes were cocultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10% FGS for 72~120 hours at 39 in a 5% incubator. The cultured nuclear transplant embryos were stained with Hoechst 33342 solution and the number of cells were counted by fluorescence microscopy. The successful injection rate of 8-, 16- and 32-cell-stageblastomeres into enucleated oocytes was 86.7, 91.0 and 93.9%, respectively. The electrofusion rate of 8-, 16- and 32-cell-stage blastomeres with enucleated oocytes was 93.3,89.3 and 79.0%, respectively. Development of blastomeres to blastocyst was similar with 8-,16- and 32-cell-stage donor nuclei(26.2, 25.8 and 26.6%, respectively, P<0.05). The mean number of cell cycle per day during in vitro culture in nuclear transplant embryos which received 8-, 16- and 32-cell- stage nuclei was 1.87, 1.81 and 1.43, respectively.

The long term goal of this research is to develop an efficient procedure for large scale production of genetically identical or cloned animals. To improve nuclear transpalntation efficiency in the rabbit, this study evaluated the age of nuclear recipient oocytes on the different steps of nuclear transplantation. The ovulated oocytes in different ages were collected from the superovulated does by flushing oviducts with Dulbecco's phosphate buffered saline(D-PBS) supplemented with 10% fetal calf serum(FCS) from 13 to 15, 17 to 20 and 23 to 26 hours after hCG injection. The denuded oocytes were used as nuclear recipient cytoplasm following enucleation by micromanipulation. The blastomeres separated from the 8-cell embryos were used as nuclear donor. The enucleated oocytes receiving a blastomere in the perivitteline space were fused in the 0.28 M mannitol solution at 1.5 kV/cm, 60 sec for three times. The fused oocytes were co-cultured with the monolayered rabbit oviductal epithelial cells in TGM-199 solution with 10% FCS for 72 hours at 37 in a 5% incubator. The cultured nuclear transplant embryos and in vivo developed embryos collected at 72 hours after hCG injection were stained with Hoechst 33342 dye. Their cell numbers were counted under a fluorescent microscope. The results obtained were summarized as follows ; 1. The aged oocytes(20 hrs. post hCG) showed significantly(P<0.05) higher fusionrates(70 ~ 90%) than the recently ovulated oocytes(30.8%) 2. The aged oocytes which were electrically activated and fused at 20 hours developed to blastocyst at significantly(P<0.05) high rate, while none of the recently ovulated oocytes developed to blastocyst. 3. Even though the aged oocytes at 23~26 hours showed higher fusion rate(85.7%), not only they were inadequate to manipulate but also their developmental potential to blastocyst was highly impaired. 4. The developmental potential in vitro of nuclear transplant embryos was significantly retarded than in vivo deveolped embryos.

원전 격납건물은 프리스트레스 콘크리트 구조로 사고발생시 내부의 방사능물질이 외부로 유출되지 않도록 강재 철판을 내 측 콘크리트 면에 설치하여 압력경계를 유지하고 있다. 강재 철판은 건설시에는 콘크리트 거푸집이고 가동중에는 차폐역할 을 하게 된다. 최근 가동원전 격납건물 라이너플레이트에 일부 부식이 발생된 사례가 있는데 공칭두께 대비 10% 이상의 두께 감육부는 공학적 평가를 통해 계속사용 또는 교체를 한다. 본 논문에서는 공학적 평가를 위한 구조해석 모델 개발 시간 단축을 위해 라이너플레이트의 설계조건과 형상을 고려한 자동화시스템을 개발하였다.

This research and development analysis provides numerical analysis techniques that can be used conveniently to determining the safety of the current state and to predict the stability in the future. It also seeks to present algorithms of back analysis to develop unified management system for control, prediction, coordination, and information modeling that can reasonably handle appropriate responses to structural behavior at project sites and design changes.

In this study, the development of gravity type collecting device for nuclear dismantling through CFD simulation is shown as follows. As a result of investigating the dust removal efficiency according to the treatment air velocity of 5 m/s (low speed) ～ 30 m/s (high speed), large dusts (80 ～ 100 ㎛) As the wind speed increases, the damping efficiency decreases and the particle size of the dust behavior increases with the increase of the wind speed. As a result, the wind speed (wind speed) 5 m/s is considered to be suitable for improving the vibration damping efficiency.

건설해체공사와 유사한 특성을 갖는 원전 제염해체공사에서 구조적 리스크 관리는 매우 중요하다(DOE). 하지만 제염해체작업 중 발생할 수 있는 구조적 재난재해 및 위험요소는 크게 고려하지 않고 있다. 이로 인해, 구조적 재난 및 재해에 의해 발생할 수 있는 작업자 리스크 역시 체계적으로 정립되어 있지 않다. 또한, 재난 및 재해 그리고 리스크 분류체계는 작업의 특성(작업프로세스, 활용장비, 작업 위치 등)별로 분류되어 있지 않아 실제 해체공사를 위한 매뉴얼로 활용하기에 무리가 있다. 따라서 차폐 콘크리트 구조물 제염해체공사의 건설해체공사와의 유사성을 기반으로 작업의 특성별로 분류한 리스크를 도출하는 것은 원자력 발전소 해체공사 리스크 관리에 필수적으로 판단한다.