New Nuclear Plants

candice_84

Where can i find more information about new nuclear plant start-up procedures?

fatra2

Hi there,

What do you mean by "start-up procedures"??? Are you looking for the commission tests that are made on new plants??? Where are you from, since this will influence the answer whether you are in the US, in Europe, or somewhere else.

Cheers

Astronuc

Which new plants? Considering the new generation of LWRs will be operated more or less as are the older generation, the startup procedures will be much the same. How much detail does one expect? Is this related to power plant commissiong or a general startup following a refueling outage?

candice_84

By start-up I mean for example, when they start the reactor for the very first time, they start the reactor with 10% percent of the full power. Then they run the reactor for couples of month before going straight up to the full power. I'd like to find information about why they don't just start the reactor with its full power? How long does it take to go to full power? Why is it necessary to take those steps? In terms of reactors I prefer to know about PWR types of reactor such as AP-1000, the new EPR or Candu?

Astronuc

In the initial heat up, the reactor system is given time to heat up for cold zero power (CZP) to hot zero power (HZP) and at the same time the system is pressurized. This is actually accomplished by running the pumps, and it gives the system time to adjust, and the plant staff test various systems. With the first time, many components are checked to verify that they are performing as expected, and instrumentation calibration is checked. At temperature, they would control rod drop (scram) tests.

Criticality is achieved after withdrawing various banks of control rods, and rod worth is tested. In-core and ex-core detectors are checked.

Normally with an operating plant, the turbine will start rolling at about 15% power - give or take, and the secondar side of a PWR is given a chance to heat up. Once systems are stabilized, power ascension continues. At about 30% power, chemistry checks are performed and flux maps are taken. There is usually another hold at 50%, the about 75%, and may be a few more to look at the axial power distribution, chemistry and thermocouple readings.

Startup is also the time that operators and other plant personnel are introduced to the plant operation, although they will have had training on a simulator.

Ships are tested on a shake down cruise to test the systems and introduce the crew to operation, and I believe prototype aircraft are similarly tested.

FYI - http://www.nrc.gov/reading-rm/doc-co...r-reactors/rg/

Specifically - Reg Guide 1.68 - Initial Test Programs for Water-Cooled Nuclear Power Plants
http://www.nrc.gov/reading-rm/doc-co...068/01-068.pdf

candice_84

How Does the first heat up achieved? I assume reactor is shut down so there is no heat generation from fission. Is there an electrical heating system involved?

Xnn

Reactor Recirculation Pumps impart energy into the reactor coolant that eventually turns into heat.

candice_84

They do this test, before fueling the reactor? How long does it take to to go from Cold zero power to hot zero power? where do they bring power to run the pumps? Do you know how much power in terms of Watt requires to run the recirculation pumps?

Astronuc

Startup from cold, the primary circuit pumps are run to heat up the primary system. Depending on the capacity of the primary system, the pumps may add on the order of 5 MW per pump. This heats up the primary system and reactor. The pressurizer has a heater, but this is really to maintain heat on the pressurizer to ensure the primary circuit pressure is maintained in the operational range.

FYI - http://www.ansn-jp.org/jneslibrary/npp1.pdf

Astronuc

Here's an example from the UK.

Pre-operational tests are performed in two phases:
• Phase I: preliminary tests
• Phase II: plant functional tests (before fuel loading)

PLANT COMMISSIONING PROGRAMME