"expensive to build, complex to operate, susceptible to prolong shutdown as a result of even minor malfunctions, and difficult and time-consuming to repair." - - Rickover.
Here with everything you always wanted to know about the liquid metal cooled reactor as was to be found in the Soviet era Alfa class submarine.
A liquid metal cooled nuclear reactor, liquid metal fast reactor or LMFR is an advanced type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for nuclear submarines
The Soviet Union/Russian Navy Project 705 'Lyre' was a class of hunter/killer nuclear-powered submarines. The class is also known by the NATO reporting name of Alfa. They were the fastest class of military submarines built [only the prototype K-222 (NATO Papa class) exceeding them in submerged speed].
The Lira was a unique design among submarines. In addition to the revolutionary use of titanium for its hull, it used a powerful lead cooled fast reactor as a power source, which greatly reduced the size of the reactor compared to conventional designs, thus reducing the overall size of the submarine, and allowing for very high speeds
Two types of LFR reactor were used in Soviet Alfa class submarines of the 1970s. The OK-550 and BM-40A designs were both capable of producing 155MWt. They were significantly lighter than typical water-cooled reactors and had an advantage of being capable to quickly switch between maximum power and minimum noise operation modes.
Greater power in a SMALLER package and able to reach higher power quicker! Also more quiet. Need anything else?
LMFR HOWEVER HAVING DISADVANTAGES THOSE ASPECTS OF WHICH OUTWEIGH THE ADVANTAGES?
MORE TO FOLLOW.