29th Symposium on Fusion Technology (SOFT 2016)

O1A.1 Tritium modeling in HCPB breeder blanket at a system level: a preliminary parametrical approach

5 Sep 2016, 16:40

20m

Congress Hall 2nd floor (Prague Congress Centre)

Board: 1

Oral H. Fuel Cycle and Breeding Blankets O1A

Speaker

Elisabetta Carella (National Fusion Laboratory)

Description

Tritium behavior in a breeding blanket is a key design issue because of its impact on safety and fuel-cycle best performance. Nowadays there are only few references and any fully validated tool with predictive capabilities. Considering the difficulty in handling tritium and its fundamental role inside a fusion reactor, it is intended to prepare a simulation tool for tritium transport.In this work a preliminary model for tritium transport at system level has been developed for the HCPB breeder concept (2014), focusing on the multi-physics of the release, diffusion, permeation, recombination phenomena. The numerical technique presented here is based on EcoSimPro simulation tool, a program with an object-oriented nature which offers the possibility of mixing various disciplines by robust equation-solving algorithms. The model is based on the integration of gas flow, concentration and tritium mass transport phenomena together with the isotope interactions between tritium atoms and the atoms of the purge gas flow. Some simplified assumptions have been adopted and the achieved results have been compared with others studies obtained by other programs. With this simplification in mind, this preliminary model includes a Tritium Extraction System and the counter of all the breeder modules present in a DEMO design blanket.The study is presented with several parametrical studies which aim is to identify the most relevant parameters for implementing breeder performances concerning tritium extraction and permeation. Significant variation in the permeation rate, as in the inventory of tritium in the different components, has been obtained especially from the variation of purge gas properties (pressure, flow rate, chemical composition).After this analysis, a quite low permeation factor per day has been found (about the 0.4 % of the diary T generation), confirming that HCPB model seem to be a quite robust breeder concept in terms of tritium radiological risk.