Three Vessel Replacements at Chalk River

  • J. W. Logie


Since 1947, when Canada’s first research reactor, NRX, went critical, CRNL has been faced with the task of partially dismantling nuclear research reactors three times. In each case, twice for NRX and once for NRU, the object was the replacement of the calandria or vessel. Planning and techniques have improved from the hectic days of the first NRX calandria change in 1953, to the relatively effortless NRU vessel change in 1972. Of the many dismantling lessons learned, three stand out:
  • careful, detailed planning with time for intensive review, and practice on full-scale mockups

  • procedures designed to minimize radiation dose to personnel

  • design of special tooling to carry out dismantling operations effectively and safely

We have gained enough confidence in our ability to deal with dismantling operations that power reactor dismantling is viewed without undue pessimism. That is not to say that power reactors hold fewer difficult problems for dismantling teams than do our vessels for us. We are well aware of the much larger radiation fields associated with power reactor components, and the much greater volumes of radioactive material that future teams will have to consider. The application of techniques already at hand, the introduction of methods now being worked out, and the design of future reactors to ease radiation problems, will overcome many of the difficulties we can foresee.


Burial Ground Tube Sheet Removal Operation Thermal Shield Lift Point 
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  1. 1.
    W.B. Lewis, The Accident To The NRX Reactor On December 12, 1952, Report AECL-232, (1953).Google Scholar
  2. 2.
    W.F. Merritt and C.A. Mawson, Retention of Radionuclides Deposited In The Chalk River Nuclear Laboratories Waste Management Areas, Report AECL-4510, (1973).Google Scholar
  3. 3.
    G.W. Hatfield, Renovation Of The NRX Reactor At Chalk River, Ontario, Report WM-1, (1954).Google Scholar

Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • J. W. Logie
    • 1
  1. 1.Atomic Energy of Canada LimitedCanada

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