Re: Bacteria in Nuclear Reactors

[Peter Fear <fearp@VAX.CS.HSCSYR.EDU>]

Bob,

You make a common assumption with bacteria, that they use carbon compounds
as an energy source. That is not always the case. When I was a grad student
in microbial genetics (many years before probes were used), we had a lab
course where we grew the bacteria that the professor used for his research.
It got its energy from iron and used sulfur instead of oxygen. It only
required very small amounts of carbon to make proteins, etc. Most of the
carbon that is used by most non-plant organisms is burned in order to get
energy. Since these bacteria do not use carbon in that manner (as an energy
source), they really don't need very much - only a trace is enough.

These bacteria are anaerobic and in using the sulfur, they create H2SO4
(sulfuric acid). They are able to live in pH 1.0!

Pete

Peter Fear
SUNY Health Science Center
750 E. Adams St.
Syracuse, NY 13210

fearp@vax.cs.hscsyr.edu

-----Original Message-----

At 01:20 PM 5/12/98 -0500, you wrote:
>     Don't have my class notes anymore, so I
>     can't verify this, but I believe the report of a bacteria adapted to
>     life in a reactor is correct.

OK, I can accept the idea of bacteria that have adapted to high
temperatures (especially in water) and to high pressures (deep sea
conditions). I can even accept the idea of bacteria that have adapted to
high radiation environments (although the evolutionary sequence where the
bacteria encountered the high radiation fields isn't obvious to me).

What I can't see is a bacteria colony in primary coolant water of a power
reactor. The control of water chemistry is such that I think we would also
be looking at a bacterium that has somehow adapted to starvation, and I
don't think that likely.

Once a reactor is opened, bacteria could get in and perhaps thrive on the
surface in a substantial gamma radiation field, but there would be a food
supply from the air. Once the reactor was closed up again, the bacteria, if
not filtered out, would face starvation. Hard to adapt to that.

Or am I missing something?

---------
Bob Flood
Dosimetry Group Leader
Stanford Linear Accelerator Center
(650) 926-3793
bflood@slac.stanford.edu