Related Rule
South Africa
Practice Relating to Rule 42. Works and Installations Containing Dangerous Forces
South Africa’s LOAC Manual (1996) provides:
The LOAC grants particular protection to the following categories of persons and targets which are termed “protected targets” … Protected places include the following: … installations containing dangerous forces (e.g. dams and nuclear electrical power stations). 
South Africa, Presentation on the South African Approach to International Humanitarian Law, Appendix A, Chapter 4: International Humanitarian Law (The Law of Armed Conflict), National Defence Force, 1996, § 29(b)(ii); see also § 22.
South Africa’s Revised Civic Education Manual (2004) states: “Protected places include … installations containing dangerous forces (e.g. dams and nuclear electrical power stations).” 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 51(b).
The manual also provides that “[a]ny unlawful attack on a clearly recognised … work or installation containing dangerous forces” is a grave breach of the law of armed conflict and a war crime. 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 57.