The article discusses the operating principle and design of the environmentally safe reactor of the heat source - K&RK generator invented by the authors based on a new initiation method for cold fusion reaction in ordinary water. The paper demonstrates the result of the action of the K&RK generator as a new type of heat source whose yield turns out to be positive for the first time in world history without any additional energy sources connected to the device. It contains a short overview of the physical nature of the initiation method of cold fusion reactions in ordinary water making a revolutionary change in the power industry.