Design of a very low inventory tritium fill system for NIF cryogenic targets

In this report we finalize our conclusions concerning the issues that determine the feasibility of a low-inventory NIF target filling system: 1) calculation of the basic physical (thermodynamic, thermal flow, strength, etc.) characteristics; 2) choice of the optimum technological sequence; 3) choice of the principal design. To make discussion easier, in this report we present more or less detailed sketches of the filling system assembly inexplicit form. Since some of the already available important physical-engineering solutions (for instance, the design of the capsule removal device) are not know to us, we left certain engineering questions open for further discussion and detalization. Summing up very briefly, we show that a very low-inventory filling system is undoubtedly feasible, notwithstanding some lingering ambiguities (for example, choice of the auxiliary capacity design, pressure gauge principle, etc.). Our previous evaluation [1] of the general concept of the low-inventory filling system was based on calculations for normal D{sub 2}. The recalculation to the 50-50% D{sub 2}-T{sub 2} mixture, reported here, does not change much in either final figures, or conclusions. We do not formulate anew the overall concept but refer to Part III of Agreement. We either omit some of our previous reasonings and evaluations, referring the reader to 1st Quarterly Report [1]