.(. i I i U AECL-9999 ATOMIC ENERGY ( ^7 \'">•) ENERGIEATOMIQUE OF CANADA LIMITED VJ^A / DU CANADA LIMITEE FUSION-BLANKET FABRICATION DEVELOPMENT AND IRRADIATION TESTING COUVERTURE DE REACTEUR A FUSION - MISE AU POINT DE LA FABRICATION ET ESSAIS SOUS IRRADIATION I.J. HASTINGS, A.J. ELLIOT, J.M. MILLER, B.J.F. PALMER and R.A. VERRALL Presented ai the 10th Annual Conference of the Canadian Nuclear Society Ottawa, Ontario, 1989 June 4-7 Chalk River Nuclear Laboratories Laboratoires nucleates de Chalk River Chalk River, Ontario KOJ 1J0 June 1989 juin ATOMIC ENERGY OF CANADA LIMITED FUSION-BLANKET FABRICATION DEVELOPMENT AND IRRADIATION TESTING I.J. Hastings**, A.J. Elliot+, J.M. Miller**'**, B.J.F. Palmer and R.A. Verrall 10th Annual Conference, Canadian Nuclear Society, Ottawa, Ontario 1989 June 4-7 Program Cofunded by Atomic Energy of Canada Limited Research Company and Canadian Fusion Fuels Technology Project ** Member, Canadian Nuclear Society System Chemistry and Corrosion Branch Chemical Engineering Branch Fuel Materials Branch Chalk River Nuclear Laboratories Chalk River, Ontario KOJ 1J0 1989 June AECL-9999 CFFTP-G-8915 l-NKRCll' ATOMIQUE DU CANADA LIMITEE COUVERTURE DE RÉACTEUR À FUSION - MISE AU POINT DE LA FABRICATION ET ESSAIS SOUS IRRADIATION* I.J. Hastings, A.J. Elliot, J.M. Miller, B.J.F. Palmer et R.A. Verrall 10e Conférence annuelle de la Société nucléaire canadienne, Ottawa, Ontario du 4 au 7 juin 1989 RÉSUMÉ Le programme de couverture de réacteur à fusion aux Laboratoires nucléaires de Chalk. River, financé conjointement par EACL et le PCTCT, vise la mise au point de la fabrication et les essais sous irradiation de la couverture. Les efforts canadiens de mise au point de couches fertiles solides sont concentrés sur le concept Spherepac. Les sphères, fabriquées par un procédé utilisant l'extrusion, sont solides, résistent à des cycles de chauffage rapides et présentent une taille de grain d'environ 1 jum. La résistance à la chaleur, la tenue mécanique et le rapport libération-production de tritium des sphères fabriquées par ce procédé font l'objet d'une caractérisation détaillée. Lors de l'irradiation en capsule à event CRITIC-I du Li20, on a obtenu une combustion massique totale du lithium de 1 % et on a recueilli 2100 Ci (70 TBq) de tritium au cours d'une période d'irradiation de ?A mois. On participe également aux efforts sur le concept de solution aqueuse de sels de lithium (ALSB). On a réalisé la radiolyse en cellule gamma de solutions aqueuses de sels de lithium à l'appui du concept et retenu l'hydroxyde de lithium pour les prochains essais en réacteur. Le Canada participe actuellement au projet BEATRIX-II, qui comprendra la mise à l'essai des sphères de zirconate de lithium de fabrication canadienne à l'installation FFTF, à Hanford, réalisé en collaboration avec le Japon et les É.-U. Service des Matériaux pour combustibles Laboratoires nucléaires de Chalk River Chalk River (Ontario) KOJ 1J0 1989 juin AECL-9999 CFFTP-G-8915 *Programme financé conjointement par la Société de recherche d'Énergie atomique du Canada limitée et le Projet canadien sur la technologie des combustibles thermonucléaires. ATOMIC ENERGY OF CANADA LIMITED FUSION-BLANKET FABRICATION DEVELOPMENT AND IRRADIATION TESTING* I.J. Hastings, A.J. Elliot, J.M. Miller, B.J.F. Palmer and R.A. Verrall 10th Annual Conference, Canadian Nuclear Society, Ottawa, Ontario 1989 June 4-7 ABSTRACT The fusion-blanket program at Chalk River Nuclear Laboratories concentrates on fabrication development and irradiation testing. Canadian efforts to develop solid-breeder blankets are focused on the sphere-pac concept. The spheres, fabricated by an extrusion-based process, are strong, survive rapid heating cycles, and have an average grain size of about one micrometre. In the recently completed CRIT1C-I vented-capsule irradiation of Li.,0, a total lithium hurnup of 1% was achieved, and 2100 curies+of tritium collected, over the 21-month irradiation. We are also participating in the development of an aqueous lithium salt blanket concept and lithium hydroxide has been chosen for further in-reactor studies. Canada is participating in the BEATRIX-II project, which will test Canadian-fabricated lithium zirconate spheres in FFTF, Hanford, with Japan and the US as the other partners. We are also members of the JAERI (Japan) Tritium Project, to improve blanket neutronics data. *Program cofunded by Atomic Energy of Canada Limited Research Company and Canadian Fusion Fuels Technology Project + 2100 curies equal 70 TBq. Fuel Materials Branch Chalk River Nuclear Laboratories Chalk River, Ontario KOJ 1J0 1989 June AECL-9999 CFFTP-G-8915 1. INTRODUCTION Canada is making significant contributions to the worldwide effort to develop fusion as an energy source. The lead agency in the Canadian program is Atomic Energy of Canada Limited (AECL) through the National Fusion Program, and major components are the Tokamak at Varennes, Quebec and the Canadian Fusion Fuels Technology Project (CFFTP) in Toronto, Ontario. A program eofunded by AliCL and CFFTP, and focusing on fusion-blanket technol- ogy, began at Chalk River Nucleai Laboratories (CRNL) in 1983. The program was based on AECL's generic expertise in ceramics, irradiation testing and tritium technology, all key aspects in developing a breeder blanket. This paper updates the status of the program (1). The major components discussed are lithium-ceramic fabrication development, in-reactor testing, and work on an alternate concept, the aqueous lithium salt blanket (ALSB). Particular emphasis is given to the recently completed CRITIC-I experiment (CRITIC - Chalk River In-reactor Tritium Instrumented Capsule), now in the post- irradiation examination phase. Additionally, progress in international aspects of the program is outlined. 2. FABRICATION DEVELOPMENT Canadian efforts to develop solid-breeder blankets focus on sphere-pac. AECL has substantial generic expertise through its experience with the concept in fission-fuel development (2). Sphere-pac blankets for fusion application require large numbers of tritium-breeding lithium-ceramic spheres. These are randomly packed into dense beds within the blanket modules incorporated into a fusion reactor. Because of their relatively small size, typically about 1 mm diameter, large numbers are required to fill a blanket bed. For example, a small-scale irradiation test on a 1-litre sphere bed requires in excess of 1 000 000, 1 mm diameter spheres. A full-size sphere-pac breeder blanket would be about 300 000 litres in volume, requiring more than 3xl0ll, 1 mm diameter ceramic spheres. Work is under way at CRNL to develop technology for high-speed production of lithium aluminate and lithium zirconate spheres. Lithium aluminate is a well- established candidate for blanket application. Lithium zirconate has recently shown attractive low-temperature tritium-release properties during in-reactor rests (3). Emphasis in the fabrication program is on achieving the high production rates required to produce the large numbers of spheres necessary for a blanket module. Pilot-scale equipment capable of producing 1 mm spheres at the rate of 250 000 spheres per minute is currently being installed and commissioned. To date, more than 1 000 000 prototype lithium aluminate spheres have been produced at CRNL by the production process, based on extrusion. The spheres are mechanically strong, survive rapid heating cycles and have an average grain size of about 1 micrometre. In particular, the small surface-to-centre temperature differential (AT, less than 20°C), inherent in the sphere concept, provides one of its major advantages (4). Long-term irradiation testing (5) has identified cracking due to large ATs as a potential problem for blanket designs based on pellets or monolithic assemblies. In addition to the development of a production process, good progress has been made in lithium-based powder synthesis. While lithium aluminate is available in industrial quantities via custom order, only small amounts of lithium zirconate have been produced worldwide. At CRNL, the precipitation technique has shown itself to be not feasible for quantity production. Current efforts focus on the solid-state reaction between zirconia and lithium carbonate. The thermal, mechanical and tritium-release performance of spheres prepared by the extrusion-based process will be characterized in detail. An in-reactor CREATE (Chalk River Experiment to Assess Tritium Emission) test has just been completed on lithium aluminate spheres. In addition, high-flux irradiation tests are planned in the CRITIC facility of the NRU reactor at CRNL, and in the Fast Flux Test Facility (FFTF) at Han ford, Washington, as part of the BEATRIX-II program (International Breeder Exchange Matrix). 3. IRRADIATION TESTING Two types of ceramic-blanket irradiation testing are performed at CRNL: CREATE tests, in which tritium-release information is obtained via post- irradiation annealing, and CRITIC tests, which permit on-line monitoring of tritium release as the irradiation progresses. Nine CREATE tests have been performed on lithium oxide and lithium aluminate, examining the effects of temperature, microstructure, sweep-gas composition and capsule material (oxygen potential) on the amount and form of tritium release. Full details of these tests are given elsewhere (6-8). The recently-completed CRITIC-I test in the NRU reactor at CRNL has produced a substantial amount of reactor-relevant data. Annular Li2<) pellets (30 mm I.D. x 40 mm 0-D.) were fabricated for CRITIC-I at Argonne National Laboratories under the BEATRIX-I program coordinated by the International Energy Agency (.TEA). The fabrication techniques and characterization results for CRITIC-I are described in detail elsewhere (9-12). The total weight of Li20 irradiated was 103 g, density 91.5% of theoretical, original isotopic content was 1.53 wt% ^Li and average grain size was 50 urn. The temperature of the ceramic was controlled by varying the composition of a He-Ar insulating gas layer (gap gas).