Re: Ada and the NMD

[Steve Howard <stephen.e.howard@lmco.com>]

David Bolen wrote:

> Richard Riehle <richard@adaworks.com> writes:
>
> > Ada, once it is understood on its own merits instead of as a
> > military-only programming language, may prove just as valuable for
> > certain software applications.  I note you are from Boeing.
> > Certainly, Boeing has found some virtue in Ada for some
> > products. Also, since this discussion involves nuclear energy, it
> > would be remiss of us to overlook the fact that some of the newest
> > nuclear power plants under construction (alas, not in the United
> > States) will have software developed in Ada.
>
> Anyone know what current US plants are using for their control systems?

Relay logic.

Although it has been a few years (12, to be exact) since I worked in the
nuclear industry, my guess is that things have not changed significantly in
that time frame.

At that time, AFAIR, there was no computer control of any of the
safety-related systems of any commercial reactor. The systems used were
purely relay and electronic logic based. Even one of the last reactors
commissioned, completed ca. 1990 (Nine Mile Point Unit II in Oswego, NY) did
not use computers for controlling the reactor. Some auxiliary systems used
computers for control (rad waste processing). Computers served almost
exclusively a monitoring role. The main plant computer collected data for
display, and to use for fuel calculations, but the reactor controls and
instrumentation used analog gauges, meters, and controls. Other computer
systems monitored radiation levels, meteorological conditions, etc., mostly
for use in emergency preparedness. In my experience, these were programmed in
assembly or FORTRAN.

Around that time, some plants were installing digital feedwater control
systems, replacing the older control systems. I did not have any exposure to
these systems, but the were probably micro-controller based.

Steve

--
Steve Howard
Lockheed Martin Naval Electronics & Surveillance Systems-Syracuse
stephen.e.howard at lmco dot com
(315)456-7579