Indian Point was an efficiency disaster from the start-up. Probably
due to the inability of the main turbine condensers from operating down
to 1" hg. absolute. No one ever found out why the plants thermo
cycle was so way 'out of whack'. Suggestions were posed but never
proved that the condensation on the condenser tubes was not film-wise
condensation but some sort of 'wierd' drop-wise or mixture condensation
..... and no one ever found out why.

In article , daestrom
wrote:

"Jere Lull" wrote in message
...
In article ,
Neon John wrote:

Even Roland's appreciation of the "big picture" is incorrect. Modern
supercritcal fossil plants achieve overall efficiencies in the 50%
range.
Even the good old nuke are in the high 30s. The Sequoyah Nuclear Plant
where
I worked for about 10 years recently replaced the steam generators. The
improved design plus some plant upgrades pushed the efficiency to 38%
and a
fraction, something that spawned a small staff party. Oh, and BTW,
Roland,
the waste heat goes up the cooling tower stacks and not into the lake,
at
least not to any significant extent. Much to the chagrin of local
fishermen
who discovered that the warm water (pre-cooling towers) spawned great
fish
growth and fishing conditions.
John De Armond

Depending on *how* it's measured, efficiency can be higher. Back in '70,
I worked as a co-op at the Eddystone plant (Philly area), then arguably
the most efficient plant in the world -- only the USSR supposedly had a
better one. Steam started at 4,999.5 psi according the gauge, ended in
partial vacuum. They burned (actually closer to exploded) 1-200 tons of
coal an hour and we STILL needed heaters in the "basement" labs in the
winter. [yes, we had walls ;-)] They only used the gas turbines (jet
engines) in the yard when absolutely necessary, because their efficiency
was so low.

By each measure, efficiency was pretty high.

But are they making plants like that any more? When they built units 3 &
4, they went back to a "mere" 1-2000 psi. AFAIK, only one supercritical
production nuke was built: Peachbottom.

Indian Point I (long shutdown now) was a nuke that used the reactor to make
saturated steam, then used an oil-fired superheater to superheat the steam.
Not sure how hot it ran, but pressure was only about 1000 psi (due to the
limits of the nuke's steam-generator).

In recent past, the industry has been going for combined-cycle gas-turbine.
Less pollution controls needed and overall cycle efficiencies running close
to 60%. But this has raised demand on natural gas, so that price has
started to climb and things are shifting once again.

daestrom