Can nuclear power plants deliver on all the attributes U.S. energy secretary Rick Perry claims

October 11, 2017

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 October 11

The U.S. has finally recognized the potential attributes that nuclear  power generation brings to the power grid. “US energy secretary Rick Perry has called on the Federal Energy Regulatory Commission (FERC) to act swiftly to address threats to grid resiliency through market reforms to recognise the attributes of baseload generation sources including nuclear”, and, “Traditional baseload generation, with on-site fuel supplies and the ability to provide voltage support, frequency services, operating reserves and reactive power, is essential to provide resiliency during events like the Polar Vortex of 2014, and more recently hurricanes Harvey, Irma and Maria, Perry said”. Also, “Perry’s proposed rule would allow for the recovery of costs of “fuel-secure generation units that make our grid reliable and resilient”. To be eligible, units must be located within FERC-approved organised markets; be able to provide “essential energy and ancillary reliability services”; and have a 90-day fuel supply on site. They must also be compliant with all applicable environmental regulations” (Reference 1).
 
Question is, can U.S. nuclear generation deliver on those attributes.

This is what the United States Nuclear Regulatory Commission (U.S. NRC) says, (Reference 2)

“Nuclear Power Plants (NPPs) are designed as base load units and are not designed to load follow (either by plant operator action or automatically via external control signal). While operators can adjust power in general, rapid changes are difficult and power changes are most problematic near the end of a fuel cycle (typically 18 months) where reactor power control is more complicated.
NPPs control systems will not be interfaced with or controlled from grid network control systems. Control of a NPP has to be handled by the NRC licensed operators to ensure nuclear safety.”

Thus in the U.S. it looks as if nuclear plants are not licensed to provide attributes like dispatchable load-following, automatic generation control (AGC) and primary frequency response although they would provide reactive power and voltage support and they certainly have adequate on-site fuel supplies. They also provide highly reliable baseload with a 92.5 percent capacity factor in 2016. Since nuclear units are operated at 100 percent full power they would not provide operating reserves. This is not to say they cannot do all the things that energy secretary Perry claims it just means the U.S. NRC prohibits them from doing so.

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CANDU 6 Performance in 2016

March 30, 2017

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 March 29

History

The two lead CANDU 6 projects were Gentilly 2 in Quebec and Point Lepreau in New Brunswick and these were quickly followed by Embalse in Argentina and Wolsong, now Wolsong 1, in South Korea and all came into service in the early to mid 1980s. These can be regarded as the first tranche of CANDU 6 build.

The second tranche of CANDU 6 units came with Wolsong 2, 3 and 4 in South Korea, Cernavoda 1 and 2 in Romania, and Qinshan 3-1 and 3-2 in China (the other units at Qinshan site are not CANDU), all entering service between 1996 to 2007. Each of the second tranche CANDU 6 units incorporate lessons learned from operation of the earlier units with changes to meet latest regulatory codes and standards.

More information on the CANDU 6 projects can be found in, CANDU 6 Performance in 2015 (reference 1).

Capacity Factor

The Capacity Factors are taken from the PRIS database. Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor. Capacity Factors are based on the (net) Reference Unit Power and on the (net) Electricity Supplied figures, as defined in the PRIS database.

CANDU 6 Units

Point Lepreau, New Brunswick, Canada. At the end of 2016 the lifetime Capacity Factor since start of commercial operation in 1983 was 70 percent, including the refurbishment outage. For the last four years, post refurbishment, the average Capacity Factor was 76.3 percent and the annual Capacity Factor for 2016 was 78.5 percent. Read the rest of this entry »


Enhanced CANDU 6 and NuScale SMR have capability to easily integrate wind and solar

August 17, 2016

by: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 August 17.

Nuclear power plants do not like to operate at anything less than 100 percent full power. The main reason is that capital costs for nuclear are high and fuel costs are low so fuel cost savings are negligible at reduced power while revenue losses are appreciable. Another reason is that when reactor power is reduced relatively quickly there is an increase of Xenon-135 in the fuel, a fission product, that tends to reduce reactivity and sets a limit on the rate and depth of any power reduction that can be achieved before the reactor shuts itself down, the so called “poison out”. On a CANDU this is about a 40 percent reactor power reduction to a reactor power of 60 percent after a fast power reduction. Xenon also slows the return to full reactor power. The xenon transient means that frequent power changes, down and up, in support of load following dispatches, would be difficult. Indeed CANDU was not designed to load follow although it was designed to load cycle, that is, reduce reactor power overnight and return to full power in the morning, without bypassing steam around the turbine to the condenser. Light water reactors use enriched fuel so are better able to respond to the xenon transient, at least with a fresh core.

In the past some domestic units and off-shore units (CANDU 6) did accumulate considerable good experience with load cycling, with some deep reactor power reductions, but not on a continuous daily basis. For example back in the 1980s several of the Bruce B units experienced nine months of load-cycling including deep (down to 60 percent full power, or lower) and shallow power reductions. All done without steam bypass. Analytical studies based on results of in-reactor testing at the Chalk River Laboratories showed that the reactor fuel could withstand daily and weekly load-cycling. However this load cycling capability has been configured out of the Ontario CANDUs and they presently operate continuously at 100 percent reactor power. Note that the eight units at the Bruce Nuclear Power Station load cycle when required to do so by bypassing steam around the turbine to the condenser but the reactor remains at full 100 percent power. With certain restrictions station electrical output can be reduced to around 60 percent of the full electrical output (reference 1).
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CANDU 6 Performance in 2015

March 28, 2016

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 March 27

History

The two lead CANDU 6 projects were Gentilly 2 in Quebec and Point Lepreau in New Brunswick and these were quickly followed by Embalse in Argentina and Wolsong, now Wolsong 1, in South Korea and all came into service in the early to mid 1980s. These can be regarded as the first tranche of CANDU 6 build.

The second tranche of CANDU 6 units came with Wolsong 2, 3 and 4 in South Korea, Cernavoda 1 and 2 in Romania, and Qinshan 3-1 and 3-2 in China (the other units at Qinshan site are not CANDU), all entering service between 1996 to 2007. Each of the second tranche CANDU 6 units incorporate lessons learned from operation of the earlier units with changes to meet latest regulatory codes and standards.

More information on the CANDU 6 projects can be found in, CANDU 6 Performance in 2014 (reference 1). Note that the Power Reactor Information System (PRIS) database of the International Atomic Energy Agency (IAEA) identifies the Qinshan units in China as Qinshan 3-1 and Qinshan 3-2, that is, units 1 and 2 of Phase 3 of the Qinshan Nuclear Power Project. These were identified previously (reference 1) as Qinshan 4 and 5.

Capacity Factor

The Capacity Factors are taken from the PRIS database. Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor. Capacity Factors are based on the (net) Reference Unit Power and on the (net) Electricity Supplied figures, as defined in the PRIS database. The annual Energy Availability Factor (reference 2) will only be given in this article if it is significantly different from the unit Capacity Factor.

CANDU 6 Units

Point Lepreau, New Brunswick, Canada. At the end of 2015, just over three years after refurbishment, the “refurbished lifetime” Capacity Factor was 75 percent and the annual Capacity Factor for 2015 was 74.0 percent. The lifetime Capacity Factor since start of commercial operation in 1983 was 69.7 percent, including the refurbishment outage. Read the rest of this entry »