As the global economic slow down hits hard on several sectors of the once thriving power industry, the utilities segment is now striving to find innovative ways to enhance their plants operating capacity. Several US based nuclear plants are in the process of modifying their existing fleet to achieve enhanced output. While these initiatives will increase USA’s power output, can very well be implemented in South Asia to deliver similar results. The knowledge on these procedures can be valuable for all power plants across the globe.
Power up-rate in simple terms is the process of increasing the power output of a running plant by enabling modification to existing components. Since up-rate of existing plants require less investment & little down time, many more utilities are submitting their desire to NRC (Nuclear Regulatory Commission, USA). When the NRC issues a license for a commercial nuclear power plant, the agency sets limits on the maximum heat output, or power level, for the reactor core. This power level dictates a significant role in many of the analyses that demonstrate plant safety, so the NRC’s authorization is required before a plant can change its maximum power level. Power up-rate only occurs after the NRC approves a commercial nuclear power plant’s request to augment its power.
The Beaver Valley nuclear power plant, USA. Almost half of American reactors have undergone maintenance to boost performance, often carried out alongside work to extend the reactors' working lives.
To increase the power output of a reactor, more highly enriched uranium fuel and/or more fresh fuel is required. This enables the reactor to produce extra thermal (Heat) energy and therefore additional steam, driving a turbine generator to produce more electricity.
Types of Power Up-rates:
The design of every commercial reactor has excess capacity needed to potentially allow for an up-rate, which can fall into one of three categories:
a) Measurement uncertainty recapture power up-rates
b) Stretch power up-rates
c) Extended power up-rates.
a) Measurement uncertainty recapture {MUR} power up-rates are power increases less than 2 % of the approved power level, and are achieved by implementing superior techniques for calculating reactor power. This involves the use of high-tech devices to more accurately measure feed water flow which is used to calculate reactor power.
b) Stretch power up-rates {SPU} are classically between 2 % and 7 %, with the actual increase in power depending on a plant designs specific operating margin. These involve, modest equipment replacement and little or no change to either the nuclear steam supply system {Reactor – Boiler} or turbine by limiting increase in pressure (2% to 3%) to allow sufficient mass flow margin in the high-pressure {HP} turbine. Stretch power up-rates usually involve changes to instrumentation settings but do not involve major plant modifications.
c) Extended power up-rates are greater than stretch power up-rates and EPU (Extended Power Uprate) increases the original licensed thermal power output by up to 20%. Extended power up-rates usually require significant modifications to major pieces of non-nuclear equipment such as high-pressure turbines, Feed water heaters, condensate extraction pumps, Drain pumps, Feed pumps and motors, main generators, and/or transformers.
Expected Applications for Power Up-rates:
The following information is based on the October 2008 survey of NRC licensees. Survey indicate utilities plan to submit 42 power up-rate applications in the next five years, including 21 extended power up-rates, 1 stretch power up-rates and 20 measurement uncertainty recapture up-rates. If these applications are permitted, the resulting up-rates would add another 8,683 MWt (2,894 MWe) to America’s power generating capacity.
Many Economic Returns:
There are also other benefits associated with an up-rate. Many of the existing nuclear plants have been operating for 30 years or more and require some kind of retrofits and modifications on major equipments. These and other potential plants have either completed or looking for a license renewal. Combining an up-rate with a maintenance upgrade or license extension allows some of the cost to be shared among these programs. Also utility doesn’t have to wait as long to collect the benefits of an EPU. An EPU can be brought into operation in about half the time required to license and build a new plant.
More than Replacing Components:
The success of an EPU program heavily relies on the quality of the management team, their ability to develop an effective execution plan, to schedule the work efficiently and to build valuable controls to ensure that those schedules are carried out.
It is difficult to generalize the perfect plan to complete an EPU for a given plant. Difference between previous modifications and equipment change outs to maintain plant operation all combine to make the EPU program for each nuclear plant unique.
With coal, oil and gas-fired power plants increasingly coming under criticism for damaging the environment, Nuclear energy is poised to pave the way for an important electric power generation platform for the future.
Written by Kandhan
Filed under: Business & Economy, Science & Technology, EPU, Fossil Plants, NRC, Nuclear, Power Plant, South Asia, SPU, USA
[…] the agency sets limits on the maximum heat output, or power level, for the reactor core. … http://kalugu.com/2009/06/16/nuclear-power-up-rate-will-aid-growth-to-world-power-generation/ June 16, 2009 […]
Increasing the efficiency of the existing Nuclear Power Plants looks like a renovation technique.Such approach is applicable to all industries.
Considering the closed nature of Indian set up with regard to Nuclear plants , we can only hope such trends catch up with the imagination of Indian Nuclear scientists as soon as possible.
May be, Dr. Kalam should advice our scientists on this.
With coal, oil and gas-fired power plants increasingly coming under criticism for damaging the environment, Nuclear energy is poised to pave the way for an important electric power generation platform for the future
– Kandhan
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Good article Kandhan. I am not sure if the nuclear scientists have successfully found a way to safely dispose the nuclear wastes. The entire world is stockpiling the nuclear wastes as they cant dispose it off easily. Cant imagine the amount of nuclear wastes that future generations will have at the end of this century. Research is still going on to destroy the nuclear wastes in an environmentally friendly way, i am not sure if they have successfully implemented it. As a suggestion, a follow up article on nuclear waste stockpiling and disposal would certainly benefit the kalugu readers. Certainly i am curious to know.
Regards
Ram
Ram,
Thanks for your comments.
As per your suggestion, in the near future – I will write a follow-up article on nuclear waste stockpiling and disposal.
Mr. Kandhan, Thanks for your message.Is it true that few years ago the environmentalists in and around kalpakkam protested against the careless disposal of wastes from the nuclear plant (certainly not the core nuclear waste, but some other sorts of wastes?) to the near by sea? Were there complaints that the fishermen were affected in and around kalpakkam? I just heard it from a friend. so i am not sure if something of that sort happened or its just a rumour?
Sorry, I am not aware of these incidences.
Kandhan:
Good article..What do you think is going to win in future-Thermal or nuclear?
Why are western countries not using more nuclear? although they could..
Which is cheaper
Ronin,
We need both. Also wind / solar / biomass etc and oil / gas. Diversification is key to control emission / global warming/ hazard /price.
Western countries are using nuclear – In Canada, nuclear power provides 15% of overall electricity generation and USA percentage is 20%. In France more than half of their electricity comes from nuclear.
Initial investment of Thermal is cheaper than Nuclear. But nuclear operating cost is less than Thermal.
Most of the USA nuclear plants are old. Hence they should go for some more new nuclear plants.
but Mr.Kandhan why are they not going for nuclear plants in a large scale (just 20% in USA) ..they are the ones who are more concerned about environment!! is it just the initial cost of a nuclear power plant ..thats little hard to believe..
itsme,
You are right. They are concern about Safety / lately Environment. Of course money too, it is a corporate America. Unless project is financially viable – forget it, nothing will move.
Lot of time – particular technology was chosen based on lobby groups. Although each has its own pros and cons over other, it is more of a policy decision.