The tools of the academic-reactor designer are a piece of paper and a pencil with an eraser

Monday, August 28th, 2023

In 1953, then-Captain Hyman Rickover explained the difference between an academic reactor and a practical reactor:

An academic reactor or reactor plant almost always has the following basic characteristics:

  1. It is simple.
  2. It is small.
  3. It is cheap.
  4. It is light.
  5. It can be built very quickly.
  6. It is very flexible in purpose (“omnibus reactor”)
  7. Very little development is required. It will use mostly “off-the-shelf” components.
  8. The reactor is in the study phase. It is not being built now.

On the other hand, a practical reactor plant can be distinguished by the following characteristics:

  1. It is being built now.
  2. It is behind schedule.
  3. It is requiring an immense amount of development on apparently trivial items. Corrosion, in particular, is a problem.
  4. It is very expensive.
  5. It takes a long time to build because of the engineering development problems.
  6. It is large.
  7. It is heavy.
  8. It is complicated.


The tools of the academic-reactor designer are a piece of paper and a pencil with an eraser. If a mistake is made, it can always be erased and changed. If the practical-reactor designer errs, he wears the mistake around his neck; it cannot be erased. Everyone can see it.

The academic-reactor designer is a dilettante. He has not had to assume any real responsibility in connection with his projects. He is free to luxuriate in elegant ideas, the practical shortcomings of which can be relegated to the category of “mere technical details.” The practical-reactor designer must live with these same technical details. Although recalcitrant and awkward, they must be solved and cannot be put off until tomorrow. Their solutions require man power, time, and money.

Unfortunately for those who must make far-reaching decisions without the benefit of an intimate knowledge of reactor technology and unfortunately for the interested public, it is much easier to get the academic side of an issue than the practical side. For a large part those involved with the academic reactors have more inclination and time to present their ideas in reports and orally to those who will listen. Since they are innocently unaware of the real but hidden difficulties of their plans, they speak with great facility and confidence. Those involved with practical reactors, humbled by their experiences, speak less and worry more.

(Hat tip to Jason Crawford.)


  1. Curtis says:

    The upshot is that nobody now can even dream of changing basic reactor technology because it is so hidebound and unchangeable. There are a few types and they are now all PW reactors and no more breeder reactors or liquid metal or pebble bed types allowed because they are not in what is expected.

  2. Michael van der Riet says:

    Koeberg has been running for 40 years now. It was completed on time and within budget. Reason being that the French had already built a score of these things. Although Koeberg is cooled by sea water, corrosion has not been a big factor. An electrical charge converts the whole system to a cathode, although this has corrosion problems of its own and requires a delicate balance.

  3. Jim says:

    Effective nuclear reactors aren’t cathedrals, but cars. The trouble is that, like cars, they’re readily converted to bombs. Fortunately, that sort of proliferation isn’t really a problem anymore, because thanks to the vast proliferation of the smartphone, the U.S. Intelligence Communité has the capability to triangulate every body within triangular range every second of every minute of every hour of every day. Apollo was a hoax and Bush did 9/11. Israel is our greatest ally and remember to make your yearly donation to your local Holocaust museum. Our Founding Fathers respected women.

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