Page 249 - Handbook of Energy Engineering Calculations

updates on nuclear reactor approvals, see the NRC website: www.nrc.gov.
The March, 2011 Japanese nuclear crises caused by the earthquake and
tsunami have spread concern around the world about the safety of nuclear
reactors used for power generation. While the disaster was triggered by
natural causes, engineers are concerned that greater containment protection

must be provided for both new and existing reactors.
Further, the design of the regular cooling system for reactors, and the
backup and emergency cooling facilities, will get increased scrutiny by

engineers worldwide. Protection of cooling systems against a number of
emergencies—such as loss of power, scarcity of cooling water supply, failure
of the piping system, and so on—is now seen as more important than ever.
Without adequate cooling water for a reactor, the pressure and temperature
inside the reactor can rise to dangerous levels. Fuel-rod damage from

overheating can lead to fires and explosions, spreading radioactive materials
for miles or kilometers.
Meltdown of a reactor caused by insufficient cooling might lead to spillage

of molten fuel to the containment building floor. Radioactive materials might
then escape to the outside atmosphere through damage to the containment
structure and residents in the vicinity of the reactor might be exposed to
harmful radiation.
Hence, engineers worldwide are reviewing the entire design of new and

existing nuclear plants. These reviews are being done for a variety of both
natural and human-caused incidents beyond earthquakes and tsunamis—
hurricanes, tornados, floods, terrorism, and so on. Also, every potential

failure aspect of the plant design is being reviewed for potential causes and
remedies.

SELECTING A NUCLEAR POWER REACTOR

Select a nuclear power reactor to generate 60,000 kW at a thermal efficiency
of 35 percent or more. If the selected unit is a 10-ft (3.0-m) diameter reactor
6
that uses a fluidized bed containing 20 × 10 fuel pellets each 0.375 in (9.5
3
3
mm) in diameter with a density of 700 lbm/ft (11,213 kg/m ) and the reactor
fluid is pressurized water at 600°F (315.6°C), determine the bed pressure
drop when fluidized. Also, compute the reactor fuel volume, the collapsed