Progress on Establishing Guidelines for National Ignition Facility (NIF) Experiments to Extend Debris Shield Lifetime
The survivability and performance of the debris shields on the National Ignition Facility (NIF) are a key factor for the successful conduct and affordable operation of the facility. The improvements required over Nova debris shields are described. Estimates of debris shield lifetimes in the presence of target emissions with 4 - 5 J/cm{sup 2} laser fluences (and higher) indicate lifetimes that may contribute unacceptably to operations costs for NIF. We are developing detailed guidance for target and experiment designers for NIF to assist in minimizing the damage to, and therefore the cost of, maintaining NIF debris shields. The guidance limits the target mass that is allowed to become particulate on the debris shields (300 mg). It also limits the amount of material that can become shrapnel for any given shot (10 mg). Finally, it restricts the introduction of non-volatile residue (NVR) that is a threat to the sol-gel coatings on the debris shields to ensure that the chamber loading at any time is less than 1 pg/cm{sup 2}. We review the experimentation on the Nova chamber that included measuring quantities of particulate on debris shields by element and capturing shrapnel pieces in aerogel samples mounted in the chamber. We also describe computations of x-ray emissions from a likely NIF target and the associated ablation expected from this x-ray exposure on supporting target hardware. We describe progress in assessing the benefits of a pre-shield and the possible impact on the guidance for target experiments on NIF. Plans for possible experimentation on Omega and other facilities to improve our understanding of target emissions and their impacts are discussed. Our discussion of planned future work provides a forum to invite possible collaboration with the IFE community.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15013194
- Report Number(s):
- UCRL-JC-140065; TRN: US200802%%1130
- Resource Relation:
- Journal Volume: 60; Journal Issue: 1; Conference: International Atomic Energy Agency Technical Committee Meeting on Physics and Technology of Inertial Fusion Energy Targets and Chambers, Madrid, Spain, Jun 07 - Jun 09, 2000
- Country of Publication:
- United States
- Language:
- English
Constraints on target chamber first wall and target designs that will enable NIF debris shields to survive
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conference | July 1999 |
| X-ray ablation measurements and modeling for ICF applications | report | September 1996 |
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Constraints on target chamber first wall and target designs that will enable NIF debris shields to survive
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