You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass

    Measurement and Calculation of Helium Generation in Beryllium Pebbles Irradiated in EBR-II

    Published: 01 January 2000

      Format Pages Price  
    PDF (248K) 13 $25   ADD TO CART
    Complete Source PDF (27M) 1254 $371   ADD TO CART

    Cite this document

    X Add email address send
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    Beryllium pebbles are being evaluated for their potential use as a neutron multiplier in fusion power reactors. Commercially available pebbles were irradiated in the Experimental Breeder Reactor II to study property changes and gas production. Helium production rates from fast neutron irradiation are significantly higher in beryllium than in other metals due to the low neutron energy threshold and large (n,2n)2α nuclear cross section. Furthermore, the 9Be(n,α)6He(β) reaction breeds 6Li, which has a high thermal neutron cross section for producing helium and tritium. Calculations of helium and tritium production were performed based on neutron dosimetry measurements.

    Stepped-anneal and total helium release measurements were conducted on single and multiple beryllium pebbles, from two different suppliers, Brush Wellman and Nippon Gashi Co.-Japan. The measurements were conducted to determine the total helium content for comparison with predictions, and to determine the helium release characteristics as a function of time and temperature. These data are required for fusion reactor design. Sequential helium analyses were conducted over a temperature range from 500°C to 1100°C in approximately 100°C steps. Observed helium release in both beryllium lots was nonlinear with time at each temperature interval, with each step being characterized by a rapid initial release rate, followed by a gradual slowing of the rate over time. Fractional helium release as a function of temperature was observed to be substantially different for the two lots.

    Comparisons of the measured and calculated total helium production in the beryllium agree within ±5%. This agreement validates our understanding of the reaction mechanisms, nuclear cross sections, and neutron dosimetry results, thereby demonstrating that we can confidently predict helium generation and release characteristics for the design of fusion reactors.


    helium measurements, helium release, beryllium

    Author Information:

    Greenwood, LR
    Pacific Northwest National Laboratory, Richland, WA

    Oliver, BM
    Pacific Northwest National Laboratory, Richland, WA

    Gelles, DS
    Pacific Northwest National Laboratory, Richland, WA

    Baldwin, DL
    Pacific Northwest National Laboratory, Richland, WA

    Dalle Donne, M
    Forschungszentrum Karsruhe INR, Karlsruhe,

    Kawamura, H
    JMTR, Oarai Establishment, JAERI Oarai-machi, Ibaraki-ken,

    Scaffidi-Argentina, F
    Forschungszentrum Karsruhe INR, Karlsruhe,

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP12452S