A test procedure had been written, but the authors were not aware of the unusual RBMK-1000 reactor behaviour under the planned operating conditions.[21]: 52 It was regarded as purely an electrical test of the generator, not a complex unit test, even though it involved critical unit systems. According to the regulations in place at the time, such a test did not require approval by either the chief design authority for the reactor (NIKIET) or the Soviet nuclear safety regulator.[21]: 51–52 The test program called for disabling the emergency core cooling system, a passive/active system of core cooling intended to provide water to the core in a loss-of-coolant accident, and approval from the Chernobyl site chief engineer had been obtained according to regulations.[
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