CANDU 3 transient analysis using Atomic Energy of Canada Ltd. codes

A limited number of transient scenarios were calculated using a computer code suite and input modeling provided by the Atomic Energy of Canada Limited (AECL) for the CANDU 3 design. Emphasis was placed on a large-break loss-of-coolant accident with delays in actuation of the two independent shutdown systems (shutdown rods and liquid poison injection). Although an extremely unlikely scenario, it was studied because of the potential consequences that would result from a positive void coefficient of reactivity. Results indicate that a few seconds delay in shutdown would result in quickly reaching fuel or cladding melting temperatures before the emergency core cooling system would be activated. Only small changes in the timing and consequences of the scenario result when several parameters, of potential importance to the progression of the accident, are varied. Five calculations were also performed for loss-of-off-site-power scenarios. These calculations assume that the plant failed to enter the island mode, i.e., power to the main coolant pumps was not restored using on-site power generation