21Requirement for approval of nuclear actions

21  Requirement for approval of nuclear actions  (1) A constitutional corporation, the Commonwealth or Commonwealth agency must not take a nuclear action that has, will have or is likely to have a significant impact on the environment.  (2) A person must not, for the purposes of trade or commerce:  (a) between Australia and another country; or  (b) between 2 States; or  (c) between a State and a Territory; or  (d) between 2 Territories; take a nuclear action that has, will have or is likely to have a significant impact on the environment.  (3) A person must not take in a Territory a nuclear action that has, will have or is likely to have a significant impact on the environment.  (4) Subsections (1), (2) and (3) do not apply to an action if:  (a) an approval of the taking of the action by the constitutional corporation, Commonwealth agency, Commonwealth or person is in operation under Part 9 for the purposes of this section; or  (b) Part 4 lets the constitutional corporation, Commonwealth agency, Commonwealth or person take the action without an approval under Part 9 for the purposes of this section; or  (ba) there is in force a determination under section 79E that the action may continue to be taken and the action is taken in accordance with the conditions (if any) specified in the determination; or  (c) there is in force a decision of the Minister under Division 2 of Part 7 that this section is not a controlling provision for the action and, if the decision was made because the Minister believed the action would be taken in a manner specified in the notice of the decision under section 77, the action is taken in that manner; or  (d) the action is an action described in subsection 160(2) (which describes actions whose authorisation is subject to a special environmental assessment process).