188. Water is a better coolant than a gas (like CO2, He, N2 etc.), because it

is a better neutron moderator as well.
requires comparatively smaller pumps and heat exchanger for a given heat transfer rate.
has a better heat transfer characteristics, and it can be pressurised to attain a high temperature.
all (a), (b) and (c).
✅ The correct answer is option D.

190. A boiling water reactor is the one, in which the

coolant water is allowed to boil in the core of the reactor.
coolant water, after being heated in the reactor core, generates steam in a boiler.
pressurised water is pumped into the core.
fuel and the coolant are thoroughly mixed to form a homogeneous solution.
✅ The correct answer is option A.