Radiological design aspects of the National Ignition Facility.

The National Ignition Facility (NIF) has been designed to accommodate some challenging radiological conditions. The high prompt neutron source (up to 1.6 × 10(19) neutrons per shot) results in the need for significant fixed shielding. Concrete shielding approximately 2 m thick is used for the primary (target bay) shield. Penetrations in this shield, including those required for 192 laser beams, utilities, diagnostics, and 19 shielded personnel access doors, make the design challenging. An additional 28 shield doors are part of the secondary shield. In addition, the prompt neutron pulse results in activated air within the target bay, requiring special ventilation considerations. Finally, targets can use a number of hazardous and radioactive materials including tritium, beryllium, and depleted uranium (the latter of which results in the generation of small quantities of fission products). Frequent access is required to the associated potentially contaminated volumes for experimental setup, facilitating the need for local exhaust ventilation to manage these hazards. This paper reviews some of these challenges, design considerations, and the engineering solutions to these design requirements.

Assuring operational readiness of the National Ignition Facility.

National Ignition Facility experiments involve the use of a variety of materials that generate a number of radiological issues. Along with the use of tritium and depleted uranium, shots generating neutrons create prompt radiation fields as well as fission and activation products. In order to assure readiness for these hazards, a series of readiness reviews was conducted as the hazards were introduced. Each step was built upon the previous steps, as well as the basic infrastructure and operating capability of the laser facility. A detailed preparation plan for the introduction of these hazards was developed. This included ensuring required equipment was in place and ready, all plans and procedures were developed, and personnel were trained and qualified to perform work in the environment. The approach for preparing the facility for operations under the new set of conditions, the preparations for the readiness reviews, the review process, as well as the approach to initial operations are discussed.