Hesham Khater - Academia.edu (original) (raw)

Papers by Hesham Khater

Research paper thumbnail of Assessment of dose rate profiles and accessibility inside the building of the experimental fusion reactor, ITER, during operation and after shutdown

Fusion Engineering and Design, 1998

Research paper thumbnail of Activation and Safety Assessment of the ARIES-ST Design

Fusion Science and Technology

Research paper thumbnail of Radiological assessment of target debris in the National Ignition Facility

2009 23rd IEEE/NPSS Symposium on Fusion Engineering, 2009

ABSTRACT Detailed activation analysis and dose rate calculations are performed for the different ... more ABSTRACT Detailed activation analysis and dose rate calculations are performed for the different materials under consideration for use in the target capsules and hohlraums used during the ignition campaign on the National Ignition Facility. This analysis examined the impact of using Be-Cu and Ge-doped CH capsules on the external dose received by workers during maintenance activities. Five days following a 20 MJ shot, dose rates inside the target chamber (TC) due to the two proposed capsule materials are small (~ 1 mrem/h). Gold and depleted-uranium (DU) are considered as potential hohlraum materials. Following a shot, Au will most probably get deposited on the TC first wall. On the other hand, while noble-gas precursors from the DU are expected to stay in the TC, most of the noble gases are pumped out of the chamber and end up on the cryo-pumps. The dose rates inside the TC due to activated Au or DU, at 5 days following a 20 MJ shot, are about 1 mrem/h. Dose rates in the vicinity of the cryo-pumps (containing noble "fission" gases) drop-off to about 1 mrem/h during the first 12 hours following the shot. A wait period of about 12 hours is recommended before transporting the fission gases outside the Target Bay for radchem analysis.

Research paper thumbnail of Generic radiation safety design for SSRL synchrotron radiation beamlines

Radiation Measurements, 2006

Research paper thumbnail of Radiation safety design for SSRL storage ring

Radiation Measurements, 2006

Research paper thumbnail of Activation and waste disposal of the ARIES-II tokamak fusion power reactor

15th IEEE/NPSS Symposium. Fusion Engineering, 1994

ABSTRACT

Research paper thumbnail of Activation analysis of the PULSAR-I fusion power reactor

Proceedings of 16th International Symposium on Fusion Engineering, 1995

... Hesham Y. Khater and the ARIES Team Fusion Technology Institute University of Wisconsin-Madis... more ... Hesham Y. Khater and the ARIES Team Fusion Technology Institute University of Wisconsin-Madison 1500 Engineering Drive, Madison, WI 53706-1687 ABSTRACT PULSAR-I is a 1000 MWe pulsed inductively-driven toka-mak design. ...

Research paper thumbnail of Shielding analysis for X-ray sources generated in target chamber of the national ignition facility

Nuclear Technology, 2009

... Used ports are usually shielded with hardware providing more effective shielding than that pr... more ... Used ports are usually shielded with hardware providing more effective shielding than that provided by the port covers. In this analysis, as a conservative assumption, all diagnostic and direct-drive ports are assumed to be covered with only 35 mm of aluminum. ...

Research paper thumbnail of Evaluation of Prompt Dose Environment in the National Ignition Facility During D-D and THD Shots

Fusion Science and Technology, 2009

Evaluation of the prompt dose environment expected in the National Ignition Facility (NIF) during... more Evaluation of the prompt dose environment expected in the National Ignition Facility (NIF) during Deuterium-Deuterium (D-D) and Tritium-Hydrogen-Deuterium (THD) shots have been completed. D-D shots resulting in the production of an annual fusion yield of up to 2.4 kJ (200 shots with 10¹³ neutrons per shot) are considered. During the THD shot campaign, shots generating a total of 2 x

Research paper thumbnail of Activation Analysis of the Final Optics Assemblies at the National Ignition Facility

Fusion Science and Technology, 2009

ABSTRACT Commissioning shots have commenced at the National Ignition Facility (NIF) at the Lawren... more ABSTRACT Commissioning shots have commenced at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory. Within a year, the 192 laser beam facility will be operational and the experimental phase will begin. At each shot, the emitted neutrons will interact with surroundings, activating them, especially inside the target bay where the neutron flux is the highest. We are calculating the dose from those activated structures and objects in order to plan and minimize worker exposure during maintenance and normal NIF operation. This study presents the results of the activation analysis of the optics of the Final Optics Assemblies (FOA), which are a key contributor to worker exposure. There are 48 FOAs weighting three tons each, and routine change-out and maintenance of optics and optics modules is expected. We found that the effective dose from any optics is negligible 6 days after the last shot, and that the effective dose from frames is low but should be minimized not to reach the dose limit.

Research paper thumbnail of Initial nuclear assessment for a low aspect ratio power plant

Fusion Science and Technology

Interest in the low aspect ratio (LAR) concept led the U.S. ARIES team to examine the credibility... more Interest in the low aspect ratio (LAR) concept led the U.S. ARIES team to examine the credibility of this advanced concept as a future source of fusion energy. The compactness of the LAR machine imposes severe constraints on the Cu center post (CP). The analysis showed that the lifetime of CP is limited by the Class C low level waste

Research paper thumbnail of LIBRA-SP, A Commercial Fusion Reactor Based on Near Term Technology

Fusion Science and Technology

Research paper thumbnail of Radiological dose rate calculations for the International Thermonuclear Experimental Reactor (ITER)

Research paper thumbnail of Need for Inboard Shield to Protect the Center Post of ST Power Plants

Fusion Science and Technology

Research paper thumbnail of Activation Analysis for the ITER Divertor Cassette

Fusion Science and Technology

Research paper thumbnail of Overview of neutron/proton source applications from IEC fusion devices

Transactions of the American Nuclear Society

A recent proposal for reorienting a significant fraction of the fusion program to more near-term ... more A recent proposal for reorienting a significant fraction of the fusion program to more near-term applications has been made. As part of the reoriented program, it is suggested that unique commercial products could be made from small ...

Research paper thumbnail of Post-Shot Radiation Environment Following Low-Yield Shots Inside the National Ignition Facility

Fusion Science and Technology, 2011

ABSTRACT A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been... more ABSTRACT A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been developed to estimate the post-shot radiation environment inside the facility. The model includes large number of structures and diagnostic instruments present inside the TB. These structures and instruments are activated by the few nanosecond pulse of neutrons generated during a shot and the resultant gamma dose rates are estimated at various decay times following the shot. The results presented in this paper are based on a low-yield D-T shot of 10^16 neutrons. General environment dose rates drop to below 3 mrem/h within three hours following a shot with higher dose rates observed at contact with some of the components. Dose rate maps of the different TB levels were generated to aid in estimating worker stay-out times following a shot before entry is permitted into the TB.

Research paper thumbnail of Apollo - An advanced fuel fusion power reactor for the 21st century

Fusion Science and Technology

A preconceptual design of a tokamak reactor fueled by a D-He-3 plasma is presented. A low aspect ... more A preconceptual design of a tokamak reactor fueled by a D-He-3 plasma is presented. A low aspect ratio (A=2-4) device is studied here but high aspect ratio devices (A > 6) may also be quite attractive. The Apollo D-He-3 tokamak capitalizes on recent advances in high field magnets (20 T) and utilizes rectennas to convert the synchrotron radiation directly to

Research paper thumbnail of Self-Shielding Effects in Decay Heat Calculations for Tungsten

Fusion Science and Technology

Research paper thumbnail of Safety Assessment of the Protective Gases Used in IFE Chambers

Research paper thumbnail of Assessment of dose rate profiles and accessibility inside the building of the experimental fusion reactor, ITER, during operation and after shutdown

Fusion Engineering and Design, 1998

Research paper thumbnail of Activation and Safety Assessment of the ARIES-ST Design

Fusion Science and Technology

Research paper thumbnail of Radiological assessment of target debris in the National Ignition Facility

2009 23rd IEEE/NPSS Symposium on Fusion Engineering, 2009

ABSTRACT Detailed activation analysis and dose rate calculations are performed for the different ... more ABSTRACT Detailed activation analysis and dose rate calculations are performed for the different materials under consideration for use in the target capsules and hohlraums used during the ignition campaign on the National Ignition Facility. This analysis examined the impact of using Be-Cu and Ge-doped CH capsules on the external dose received by workers during maintenance activities. Five days following a 20 MJ shot, dose rates inside the target chamber (TC) due to the two proposed capsule materials are small (~ 1 mrem/h). Gold and depleted-uranium (DU) are considered as potential hohlraum materials. Following a shot, Au will most probably get deposited on the TC first wall. On the other hand, while noble-gas precursors from the DU are expected to stay in the TC, most of the noble gases are pumped out of the chamber and end up on the cryo-pumps. The dose rates inside the TC due to activated Au or DU, at 5 days following a 20 MJ shot, are about 1 mrem/h. Dose rates in the vicinity of the cryo-pumps (containing noble "fission" gases) drop-off to about 1 mrem/h during the first 12 hours following the shot. A wait period of about 12 hours is recommended before transporting the fission gases outside the Target Bay for radchem analysis.

Research paper thumbnail of Generic radiation safety design for SSRL synchrotron radiation beamlines

Radiation Measurements, 2006

Research paper thumbnail of Radiation safety design for SSRL storage ring

Radiation Measurements, 2006

Research paper thumbnail of Activation and waste disposal of the ARIES-II tokamak fusion power reactor

15th IEEE/NPSS Symposium. Fusion Engineering, 1994

ABSTRACT

Research paper thumbnail of Activation analysis of the PULSAR-I fusion power reactor

Proceedings of 16th International Symposium on Fusion Engineering, 1995

... Hesham Y. Khater and the ARIES Team Fusion Technology Institute University of Wisconsin-Madis... more ... Hesham Y. Khater and the ARIES Team Fusion Technology Institute University of Wisconsin-Madison 1500 Engineering Drive, Madison, WI 53706-1687 ABSTRACT PULSAR-I is a 1000 MWe pulsed inductively-driven toka-mak design. ...

Research paper thumbnail of Shielding analysis for X-ray sources generated in target chamber of the national ignition facility

Nuclear Technology, 2009

... Used ports are usually shielded with hardware providing more effective shielding than that pr... more ... Used ports are usually shielded with hardware providing more effective shielding than that provided by the port covers. In this analysis, as a conservative assumption, all diagnostic and direct-drive ports are assumed to be covered with only 35 mm of aluminum. ...

Research paper thumbnail of Evaluation of Prompt Dose Environment in the National Ignition Facility During D-D and THD Shots

Fusion Science and Technology, 2009

Evaluation of the prompt dose environment expected in the National Ignition Facility (NIF) during... more Evaluation of the prompt dose environment expected in the National Ignition Facility (NIF) during Deuterium-Deuterium (D-D) and Tritium-Hydrogen-Deuterium (THD) shots have been completed. D-D shots resulting in the production of an annual fusion yield of up to 2.4 kJ (200 shots with 10¹³ neutrons per shot) are considered. During the THD shot campaign, shots generating a total of 2 x

Research paper thumbnail of Activation Analysis of the Final Optics Assemblies at the National Ignition Facility

Fusion Science and Technology, 2009

ABSTRACT Commissioning shots have commenced at the National Ignition Facility (NIF) at the Lawren... more ABSTRACT Commissioning shots have commenced at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory. Within a year, the 192 laser beam facility will be operational and the experimental phase will begin. At each shot, the emitted neutrons will interact with surroundings, activating them, especially inside the target bay where the neutron flux is the highest. We are calculating the dose from those activated structures and objects in order to plan and minimize worker exposure during maintenance and normal NIF operation. This study presents the results of the activation analysis of the optics of the Final Optics Assemblies (FOA), which are a key contributor to worker exposure. There are 48 FOAs weighting three tons each, and routine change-out and maintenance of optics and optics modules is expected. We found that the effective dose from any optics is negligible 6 days after the last shot, and that the effective dose from frames is low but should be minimized not to reach the dose limit.

Research paper thumbnail of Initial nuclear assessment for a low aspect ratio power plant

Fusion Science and Technology

Interest in the low aspect ratio (LAR) concept led the U.S. ARIES team to examine the credibility... more Interest in the low aspect ratio (LAR) concept led the U.S. ARIES team to examine the credibility of this advanced concept as a future source of fusion energy. The compactness of the LAR machine imposes severe constraints on the Cu center post (CP). The analysis showed that the lifetime of CP is limited by the Class C low level waste

Research paper thumbnail of LIBRA-SP, A Commercial Fusion Reactor Based on Near Term Technology

Fusion Science and Technology

Research paper thumbnail of Radiological dose rate calculations for the International Thermonuclear Experimental Reactor (ITER)

Research paper thumbnail of Need for Inboard Shield to Protect the Center Post of ST Power Plants

Fusion Science and Technology

Research paper thumbnail of Activation Analysis for the ITER Divertor Cassette

Fusion Science and Technology

Research paper thumbnail of Overview of neutron/proton source applications from IEC fusion devices

Transactions of the American Nuclear Society

A recent proposal for reorienting a significant fraction of the fusion program to more near-term ... more A recent proposal for reorienting a significant fraction of the fusion program to more near-term applications has been made. As part of the reoriented program, it is suggested that unique commercial products could be made from small ...

Research paper thumbnail of Post-Shot Radiation Environment Following Low-Yield Shots Inside the National Ignition Facility

Fusion Science and Technology, 2011

ABSTRACT A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been... more ABSTRACT A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been developed to estimate the post-shot radiation environment inside the facility. The model includes large number of structures and diagnostic instruments present inside the TB. These structures and instruments are activated by the few nanosecond pulse of neutrons generated during a shot and the resultant gamma dose rates are estimated at various decay times following the shot. The results presented in this paper are based on a low-yield D-T shot of 10^16 neutrons. General environment dose rates drop to below 3 mrem/h within three hours following a shot with higher dose rates observed at contact with some of the components. Dose rate maps of the different TB levels were generated to aid in estimating worker stay-out times following a shot before entry is permitted into the TB.

Research paper thumbnail of Apollo - An advanced fuel fusion power reactor for the 21st century

Fusion Science and Technology

A preconceptual design of a tokamak reactor fueled by a D-He-3 plasma is presented. A low aspect ... more A preconceptual design of a tokamak reactor fueled by a D-He-3 plasma is presented. A low aspect ratio (A=2-4) device is studied here but high aspect ratio devices (A > 6) may also be quite attractive. The Apollo D-He-3 tokamak capitalizes on recent advances in high field magnets (20 T) and utilizes rectennas to convert the synchrotron radiation directly to

Research paper thumbnail of Self-Shielding Effects in Decay Heat Calculations for Tungsten

Fusion Science and Technology

Research paper thumbnail of Safety Assessment of the Protective Gases Used in IFE Chambers