Genetic Variability Within and Among Three Ecoraces of the Tasar Silkworm Antheraea mylitta Drury, as Revealed by ISSR and RAPD Markers

( K. Vijayan ),( C. V. Nair ),( P. K. Kar ),( T. P. Mohandas ),( B. Saratchandra ),( S. Raje Urs ) 한국잠사학회 2005 International Journal of Industrial Entomology Vol.10 No.1

Genetic Variability Within and Among Three Ecoraces of the Tasar Silkworm Antheraea mylitta Drury, as Revealed by ISSR and RAPD Markers

Vijayan K.,Nair C. V.,Kar P. K.,Mohandas T. P.,Saratchandra B.,Urs S. Raje Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.10 No.1

Genetic diversity within and between populations of Antheraea mylitta Drury was studied using thirty individuals from three ecoraces using 12 ISSR and 10 RAPD primers. Rally, Daba and Modal ecoraces were collected from Chattisgarh, Jharkhand and Orissa states of India respectively. The ISSR and RAPD primers generated $94.7\%$ and $95.6\%$ polymorphism among the 30 individuals. The cluster analysis grouped these individuals according to their ecorace. The intra-ecoracial heterozygosity estimated with ISSR markers were $0.123{\pm}0.18,\;0.169{\pm}0.17\;and\;0.214{\pm}0.17$ respectively for Modal, Raily and Daba ecoraces. Like wise, with RAPD markers the intraecoracial heterozygosity was $0.17{\pm}0.22$ in Modal, $0.229{\pm}0.17$ in Raily and $0.23{\pm}0.19$ in Daba ecoraces. However, the significantly low genetic differentiation (GST) (0.182 for ISSR and 0.161 for RAPD) and the high gene flow (Nm) (2.249 for ISSR and 2.60 for RAPD markers) among the ecoraces revealed that the amount of genetic diversity present among the ecoraces is not significant enough to make drastic genetic drifts among these ecoraces in the near future.

Genetic variability within and among three ecoraces of the tasar silkworm Antheraea mylitta Drury, as revealed by molecular markers

K. Vijayan,C. V. Nair,P. K. Kar,T. P. Mohandas,B. Saratchandra,S. Raje Urs 한국잠사학회 2005 International Journal of Industrial Entomology Vol.10 No.1

Genetic diversity within and between populations of Antheraea mylitta Drury was studied using thirty individuals from three ecoraces using 12 ISSR and 10 RAPD primers. Raily, Daba and Modal ecoraces were collected from Chattisgarh, Jharkhand and Orissa states of India respectively. The ISSR and RAPD primers generated 94.7% and 95.6% polymorphism among the 30 individuals. The cluster analysis grouped these individuals according to their ecorace. The intra-ecoracial heterozygosity estimated with ISSR markers were 0.123 ± 0.18, 0.169 ± 0.17 and 0.214 ± 0.17 respectively for Modal, Raily and Daba ecoraces. Like wise, with RAPD markers the intraecoracial heterozygosity was 0.17 ± 0.22 in Modal, 0.229 ± 0.17 in Raily and 0.23 ± 0.19 in Daba ecoraces.However, the significantly low genetic differentiation (GST) (0.182 for ISSR and 0.161 for RAPD) and the high gene flow (Nm) (2.249 for ISSR and 2.60 for RAPD markers) among the ecoraces revealed that the amount of genetic diversity present among the ecoraces is not significant enough to make drastic genetic drifts among these ecoraces in the near future.

Genetic Variability in the Natural Populations of Daba Ecorace of Tasar Silkworm (Antheraea mylitta Drury), as Revealed by ISSR Markers

Mohandas, T.P.,Vijayan, K.,Kar, P.K.,Awasthi, A.K.,Saratchandra, B. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.2

Genetic diversity within the natural populations of Daba ecorace of Antheraea mylitta Drury was studied using individual silkworms collected from the South Singhbhum district of Jharkhand state of India with 21 inter simple sequence repeat (ISSR) primers. A total of 148 bands were produced, of which 79% was polymorphic. The pair wise genetic distance among the individuals varied from 0.186 to 0.329. The dendrogram grouped the individuals into 3 major clusters. Nei's heterozygosity analysis revealed 0.265 ${\times}$ 0.18 variability within the population. The high genetic variability present within the natural population of Daba ecorace of A. mylitta is indicative of their adaptational strategy in nature and have much importance for in situ conservation as well as utilization in breeding programs.

Role of Passive Safety Features in Prevention and Mitigation of Severe Plant Conditions in Indian Advanced Heavy Water Reactor

Vikas Jain,A. K. Nayak,M. Dhiman,P.P. KULKARNI,P. K. Vijayan,K.K. Vaze 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.5

Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor ‘AHWR’ is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.

ROLE OF PASSIVE SAFETY FEATURES IN PREVENTION AND MITIGATION OF SEVERE PLANT CONDITIONS IN INDIAN ADVANCED HEAVY WATER REACTOR

Jain, Vikas,Nayak, A.K.,Dhiman, M.,Kulkarni, P.P.,Vijayan, P.K.,Vaze, K.K. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5

Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor 'AHWR' is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.

Genetic Variability in the Natural Populations of Daba Ecorace of Tasar Silkworm (Antheraea mylitta Drury), as Revealed by ISSR Markers

T. P. Mohandas,K. Vijayan,P. K. Kar,A. K. Awasthi,B. Saratchandra 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.2

Genetic diversity within the natural populations of Daba ecorace of Antheraea mylitta Drury was studied using individual silkworms collected from the South Singhbhum district of Jharkhand state of India with 21 inter simple sequence repeat (ISSR) primers. A total of 148 bands were produced, of which 79% was polymorphic. The pair wise genetic distance among the individuals varied from 0.186 to 0.329. The dendrogram grouped the individuals into 3 major clusters. Nei’s heterozygosity analysis revealed 0.265 ± 0.18 variability within the population. The high genetic variability present within the natural population of Daba ecorace of A. mylitta is indicative of their adaptational strategy in nature and have much importance for in situ conservation as well as utilization in breeding programs.

Managing a Prolonged Station Blackout Condition in AHWR by Passive Means

Mukesh Kumar,A. K. Nayak,V. Jain,P. K. Vijayan,K.K. Vaze 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.5

Removal of decay heat from an operating reactor during a prolonged station blackout condition is a big concern for reactor designers, especially after the recent Fukushima accident. In the case of a prolonged station blackout condition, heat removal is possible only by passive means since no pumps or active systems are available. Keeping this in mind, the AHWR has been designed with many passive safety features. One of them is a passive means of removing decay heat with the help of Isolation Condensers (ICs) which are submerged in a big water pool called the Gravity Driven Water Pool (GDWP). The ICs have many tubes in which the steam, generated by the reactor core due to the decay heat, flows and condenses by rejecting the heat into the water pool. After condensation, the condensate falls back into the steam drum of the reactor. The GDWP tank holds a large amount of water, about 8000 m3, which is located at a higher elevation than the steam drum of the reactor in order to promote natural circulation. Due to the recent Fukushima type accidents, it has been a concern to understand and evaluate the capability of the ICs to remove decay heat for a prolonged period without escalating fuel sheath temperature. In view of this, an analysis has been performed for decay heat removal characteristics over several days of an AHWR by ICs. The computer code RELAP5/MOD3.2 was used for this purpose. Results indicate that the ICs can remove the decay heat for more than 10 days without causing any bulk boiling in the GDWP. After that, decay heat can be removed for more than 40days by boiling off the pool inventory. The pressure inside the containment does not exceed the design pressure even after 10days by condensation of steam generated from the GDWP on the walls of containment and on the Passive Containment Cooling System (PCCS) tubes. If venting is carried out after this period, the decay heat can be removed for more than 50 days without exceeding the design limits.

Sort Communication : Genetic Variability in the Natural Populations of Daba Ecorace of Tasar Silkworm (Antheraea mylitta Drury), as Revealed by ISSR Markers

( T. P. Mohandas ),( K. Vijayan ),( P. K. Kar ),( A. K. Awasthi ),( B. Saratchandra ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.2

Genetic diversity within the natural populations of Daba ecorace of Antheraea mylitta Drury was studied using individual silkworms collected from the South Singhbhum district of Jharkhand state of India with 21 inter simple sequence repeat (ISSR) primers. A total of 148 bands were produced, of which 79% was polymorphic. The pair wise genetic distance among the individuals varied from 0.186 to 0.329. The dendrogram grouped the individuals into 3 major clusters. Nei`s heterozygosity analysis revealed 0.265±0.18 variability within the population. The high genetic variability present within the natural population of Daba ecorace of A. mylitta is indicative of their adaptational strategy in nature and have much importance for in situ conservation as well as utilization in breeding programs.

MANAGING A PROLONGED STATION BLACKOUT CONDITION IN AHWR BY PASSIVE MEANS

Kumar, Mukesh,Nayak, A.K.,Jain, V,Vijayan, P.K.,Vaze, K.K. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5

Removal of decay heat from an operating reactor during a prolonged station blackout condition is a big concern for reactor designers, especially after the recent Fukushima accident. In the case of a prolonged station blackout condition, heat removal is possible only by passive means since no pumps or active systems are available. Keeping this in mind, the AHWR has been designed with many passive safety features. One of them is a passive means of removing decay heat with the help of Isolation Condensers (ICs) which are submerged in a big water pool called the Gravity Driven Water Pool (GDWP). The ICs have many tubes in which the steam, generated by the reactor core due to the decay heat, flows and condenses by rejecting the heat into the water pool. After condensation, the condensate falls back into the steam drum of the reactor. The GDWP tank holds a large amount of water, about 8000 $m^3$, which is located at a higher elevation than the steam drum of the reactor in order to promote natural circulation. Due to the recent Fukushima type accidents, it has been a concern to understand and evaluate the capability of the ICs to remove decay heat for a prolonged period without escalating fuel sheath temperature. In view of this, an analysis has been performed for decay heat removal characteristics over several days of an AHWR by ICs. The computer code RELAP5/MOD3.2 was used for this purpose. Results indicate that the ICs can remove the decay heat for more than 10 days without causing any bulk boiling in the GDWP. After that, decay heat can be removed for more than 40 days by boiling off the pool inventory. The pressure inside the containment does not exceed the design pressure even after 10 days by condensation of steam generated from the GDWP on the walls of containment and on the Passive Containment Cooling System (PCCS) tubes. If venting is carried out after this period, the decay heat can be removed for more than 50 days without exceeding the design limits.