DCLL TBM Safety Status Brad Merrill, Fusion Safety Program UCLA TBM Meeting May 10-11th, 2006

TBM Safety Workshop Summary A workshop on TBM Safety/Licensing was held April 3rd at Cadarache. The workshop participants included members of the ITER International Team (IT) (Jean-Philippe Girard, Markus Iseli, and Neill Taylor) and the TBM Safety Contact Person from each TBM Party Members from the ITER IT presented ITER’s licensing schedule and the safety input that was required from each TBM The ITER IT is presently planning to submit ITER’s Report on Preliminary Safety (RPrS) to the French Nuclear Safety Authority (NSA), which is comparable to the US NRC, in September of 2007, with the hope of obtaining a permit to construct ITER by April 2009 In order to meet this schedule, the ITER IT must have the RPrS completed by August of 2007, which means that all input to the RPrS, including TBM safety input, must be available to the ITER IT by January 2007 This input must include for both the TBM and ancillary systems: Technical description Source terms (radioactive, energy, and chemical) Operational releases Plant worker operation radiation exposure estimates

TBM Safety Workshop Summary (cont.) This input must include for both the TBM and ancillary systems (con’t): Failure modes and effects analysis (FMEA) study Consequence analysis of selected design basis accidents (DBA) and beyond design basis accidents (BDBA) Waste disposal analysis Regarding accident analyses, the ITER IT is only planning to include the bounding (worst consequence) TBM accident result in ITER’s RPrS to avoid complicating the licensing process The safety analysis performed for the DCLL, as contained in the DDD, is lacking in three areas Plant worker operational radiation exposure estimates An FMEA study to determine likely accidents Consequence analysis of accidents based on FMEA results The accident scenarios analyzed in our DDD are those specified by the ITER IT during the ITER EDA, and may or may not be those ITER would like to include in ITER’s RPrS

TBM Safety Workshop Summary (cont.) I pushed back hard on these reporting requirements for two reasons: Given the schedule ITER is on, the US does not have the resources to perform a complete FMEA, perform accident consequence analysis for seven accident categories (e.g. seven accidents), plus estimate occupational doses related to TBM maintenance An FMEA does not tell you which accidents to analyze per category (e.g. which will be the worst consequence accident) so in theory you must analyze them all By the end of the meeting, the ITER IT and TBM Parties agreed that Draft copies of EU FMEAs (already nearing completion) would be made available to all parties by June 2006 The safety sections from each TBM’s Design Description Document (DDD) would be transmitted to the ITER IT by July 2006 to start the process of assembling source term and operational release information for ITER’s RPrS; the safety sections can be either transmitted as they exist now in the DDD or revised if desired In September 2006, there will be a meeting to discuss FMEA results and select accidents from only four accident categories for each TBM Party to analyze Consequence results will be transmitted to the ITER IT by January 2007

Future Plans I plan to submit our DDD safety section with little or no changes, which means a larger TBM with higher: radioactive source inventories, tritium production rates, decay heating, and PbLi flow rates than presently envisioned, because I do not have enough funding to shoot at a moving target during this process I would like to revise the tritium operational release calculation in our DDD because the DCLL TBM operational releases were considerably higher than other TBM estimates. I would like to include the permeation reduction afforded by the SiC FCI in the PbLi outer pipe and possibly increase the length of the permeator tubes. To include the FCI, I need an estimate from the team on the fraction of PbLi that flows in the gap between the FCI and outer FS pipe. I plan to use most of the EU HCLL TBM FMEA for our TBM, and have Lee Cadwallader at the INL complete our FMEA by including the PbLi cooling systems After September, new accident analyses will be performed on the TBM and TBM ancillary systems as they appear in the DDD and the results submitted to the ITER IT by the end of December I did not reach an agreement with the ITER IT regarding occupational exposure estimates. My proposal was to base TBM dose estimates on those already being developed for the ITER device scaled by radioactive contact dose (e.g., scaled from divertor maintenance doses) Beyond the RPrS, the ITER IT is asking for a fully developed Dossier on Safety for each TBM similar to the RPrS in scope