What are the advantages and disadvantages of using nuclear fission to power electrical generating plants and submarines?

Answer 1

There are quite a few advantages to nuclear propulsion on a submarine.

1. Operational cost - While up-front construction costs are expensive, long term maintenance and operational costs are lower given the lack of need for fuel supplies for the main engines.

2. Range - Nuclear powered boats have unlimited range between refueling stops ( 5-10 years), and are only limited by crew / maintenance requirements. By comparison, their Diesel-Electric counterparts are limited in range by the amount of fuel they can carry.

3. Tactical Speed - All modern nuclear submarines are designed to escort/scout ahead of fleets/battle groups, and as such have great sustainable speed underwater (the old Russian ALFA fast-attack was known to achieve 45 knots submerged). DE boats just don't have that capability, as it drains their batteries too quickly.

Speed is also a great advantage when there's a torpedo headed toward you and you need to evade it.

4. Tactical Equipment - With increased electrical generating capacity comes increased equipment capability, and therefore overall tactical capability. Even in bigger boats, they just cram in more equipment; crew habitation comes second, though it's fairly comfortable by most shipboard standards.

5. Atmospheric Regeneration - Nuclear power allows for machines that constantly regenerate the atmosphere while submerged, generating oxygen and removing Carbon Monoxide/Carbon Dioxide/Particulates from the air. DE submarines do have regeneration capability, but it's limited, and that also limits crew size and overall tactical capability.

Even so, the air does get a bit stale after a couple of months if you don't bring in fresh air.

6. Water generation - Water distillation achieved by using the steam from reactor allows for thousands of gallons of water to be made daily for crew use.

7. Civilian Emergencies - Most people don't realize it, but all nuclear powered vessels have the capability of reversing their electrical generation flow from ship to shore in the event a city or town loses its power generation in a disaster. The amount of water generated can also provide thousands of gallons of fresh, potable water to disaster survivors.

There are three disadvantages to nuclear propulsion:

1. Spent fuel rods - The first is the need to deal with the used fuel. In years past, spent fuel was recycled into weapons-grade material for nuclear weapons, but since arms limitation treaties were signed, spent fuel has become a problem, particularly since environmentalists keep trying to block the opening of the Yucca Mountain Nuclear Waste disposal site.

In coming years this won't be as much of a problem, as there is development proceeding on "lifetime fuel", or reactors that are fueled for the life of the submarine.. This means that they won't have to refuel every several years as they do now, but will go 30 or more years before the need arises.

2. Sinking - If a nuclear powered boat sinks from enemy action or accident, radiation can possibly enter the ocean, but this hasn't yet proven to be a problem with the several known boats that have sunk over the past 50 years. Submarine reactor vessels are constructed to withstand extreme pressures and explosion damage to avoid such problems.

3. Noise - All nuclear powered boats, as do shore reactors, use active cooling systems, which mean active machinery coolant pumps. The main engines and turbine-generators are also powered by steam generated by the reactor.

The additional noise generated by the steam and machinery makes nuclear powered boats much noisier than their DE counterparts; however, advances over the past 50 years in ship silencing have reduced the underwater noise range of nuclear powered boats to rival that of DE submarines running on the battery.