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I don't think Combustion Engineering and Babcock & Wilcox are
still in business. They probably have been bought by some other organization.
Babcock & Wilcox originally had 9 plants, but two are shutdown permanently.
These are the ill fated Three Mile Island plant in Pennsylvania and Rancho Seco
in California. More on these later.
The term PWR means pressurized water type plants
and BWR means boiling water type plants. The PWR plants operate with pressurized
single phase water systems whereas the General Electric BWR plants boil water in the reactor
and the steam goes directly to the turbine.
Most of the commercial nuclear reactor plants are going on thirty
years old. They have served us well and have operated safely during that time. Most of these plants are
going through or have gone though a re-licensing function. But how long will they
be around? They will have to be eventually replaced. What will we use for the additional electric energy due
to population growth and the need for replacements? I submit that renewables will not be a significant
contributor. Conservation and renewable energy systems, as the religious and
environmentalists organizations suggest, will certainly not suffice.
A Moody's Investor Service Report.
Oct. 13, 2004 – As the cost of generating electricity from fossil-fueled power
plants has risen in recent years due to climbing fuel costs, the competitive
advantage of nuclear power plants has grown, a new report issued by Moody’s
Investors Service concludes.
“Nuclear plants have become extremely attractive due to their competitive cost
structure … In fact, as nuclear plants continue to operate above 90% capacity,
nuclear power should continue to compete well against almost any form of power
with the exception of hydroelectric utilities, which have no fuel costs,” states
the report released in late September.
The report is entitled, “U.S. Nuclear Assets Remain Attractive Acquisition
Targets; With Potentially Favorable Credit Implications for Efficient
Operators.” It is the third report in a series of special comments by Moody’s on
the U.S. nuclear energy industry.
The average electricity production cost (fuel and operations and maintenance)
at nuclear power plants in 2003 was 1.72 cents/kilowatt-hour (kWh), according to
data from the Federal Energy Regulatory Commission and the Electric Utility Cost
Group. The average production cost at coal-fired power plants was 1.8 cents/kWh;
at natural gas-fired power plants was 5.77 cents/kWh; and oil-fired plants was
5.33 cents/kWh, according to the FERC/EUCG data.
While the pace of plant acquisitions has slowed the past few years, “owners of
multiple nuclear plants continue to be interested in acquiring nuclear
facilities because well-operated plants are low-cost, competitive, and reliable
sources of generating capacity that can be counted on well into the future,” the
report states.
Of the 103 reactors operating in 31 states, ownership
of 70 is concentrated in the hands of 10 investor-owned utilities, the report
notes. The largest owners include: Excelon, Entergy, FPL Group, Progress Energy,
Duke Energy, Southern Co., First Energy, Constellation, Dominion and Public
Service Enterprise Group.
Capacity Factors
It is significant to note that the capacity
factors of the nuclear plants are between 89 an 91 percent if we exclude the B &
W plants. Recall that the capacity factors of wind and solar system values range between 15 to 22 percent. This means that the nuclear plants generate
approximately 89/20 =
4.5 times more electric energy per installed kWe capacity. This fact alone demonstrates
that nuclear has an enormous economic advantage over the renewable energy
systems. The cost of electrical energy is inversely proportional to the capacity
factor. In other words the energy system gets paid in proportion to the amount
of electrical energy it produces.
Babcock & Wilcox
What went wrong with Three Mile
Island?
The accident at the Three Mile Island Unit 2 (TMI-2)
nuclear power plant near Middletown, Pennsylvania, on March 28, 1979, was the
most serious in U.S. commercial nuclear power plant operating history, even
though it led to no deaths or injuries to plant workers or members of the nearby
community. But it brought about sweeping changes involving emergency response
planning, reactor operator training, human factors engineering, radiation
protection, and many other areas of nuclear power plant operations. It also
caused the U.S. Nuclear Regulatory Commission to tighten and heighten its
regulatory oversight. Resultant changes in the nuclear power industry and at the
NRC had the effect of enhancing safety.
The nine B & W plants deserve an explanation
because one of them, the Three Mile Island plant had the worst ever accident
that ruined the plant. The other plant, Rancho Seco, experienced temperature
transients that scared the owners and it was abandoned. My understanding
of the Three Mile Island accident is the following:
All of the B&W plants were fitted with
once-through steam generators. This type of unit does not have a large reserve
of water as the recirculation boilers do. This was part of the problem. The
accident started when a condensate pump tripped and stopped the feedwater flow
to the steam generators. The low feedwater flow caused the reactor
primary water side to heat up immediately. This caused the primary system
pressure to rise. The pressure relief valve on the pressurizer open as it should
have and relieve the over pressure by venting the steam to a holding tank
located in another building. The accident really was initiated because the
relief valve stuck open and allowed the primary system to depressurize. But the
reactor emergency core sprays operated and sprayed water into the reactor vessel
to prevent the fuel elements from over heating . The reactor shutdown as it was
supposes to do. Now the gross operator error occurred. When the holding tank in
the other building over flowed the operators thought there was too much water
flow and they shut off the emergency reactor core sprays. The reactor core went
partially dry and some of the fuel elements melted. Thus it
was a mess, but it did become under control without radioactive fission products
exhausted to the atmosphere. No one was over exposed to radiation. But the plant
was a mess and could not be recovered.
An important lesson was learned. The control and
operating functions of the safety grade systems should be isolated in a
compartment
where the operators cannot shutdown or compromise the safety system operations
in any manner. Safety grade systems for a nuclear reactor plant have always been
designed to be very reliable and redundancy is provided. They are tested and the
reliability is verified statistically.
In fact the Russian Chernobyl plant failure was
initiated because the operators were in a hurry to get some routine testing done
and they shutoff the safety control systems. Also the Russians do not use a
containment vessel around their primary reactor systems. This would have
tremendously mitigated their accident.
After the event of Three Mile Island and the
thermal temperature transients of Rancho Seco, the B&W units have been operated
safely.
Rancho Seco
Rancho Seco was another Babcock Wilcox plant identical to
Three Mile Island. It was owned and operated by the Sacramento Municipal Utility
District (SMUD). The plant was located just South of Sacramento.
The problem was also due to the once through steam generators. A small unbalance
between the feed water and primary system flow resulted it thermal transients
that scared the SMUD operating crews. The utility district just
decided to give up and walk way from the plant. They did not have the technical
acumen as Duke Power did. The latter simply improved the control systems and
startup power level so that
the thermal transients did not occur.
SMUD was supposed to have a highly qualified nuclear engineer
in charge of the project. It was reported in the newspapers that manger's
last job was with a transit district in Philadelphia.
Epilogue
Before nuclear power can
re-emerge in the US, three actions must be undertaken:
-
The manufacturing industry must gear up
to make the components that go into a nuclear power plant. The industry has
been shut down for 20 odd years and there is no present manufacturing base.
If there is only one order for a plant we would have to get most of the
components manufactured in overseas..
-
The reactor manufacturers and
owners must be protected against frivolous law suits. In the past the
environmentalists would stop all progress with ridiculous law suites that
would delay the progress for up to ten years. This can double or
triple the capital cost of the plants.
-
Allow for fuel reprocessing to
lower fuel costs and reduce the volume of fission products that must be
stored and protected.
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