KR20180061497A - Loading pattern of Cobalt Bundle - Google Patents

Abstract

The present invention relates to a method for designing a cobalt bundle of a heavy water power plant which includes the step of designing a pattern without fluctuation in reference output when designing the pattern for loading the cobalt bundle of the heavy water power plant in a core. In order to minimize a core output distribution for carry and usage by discharging the cobalt bundle at a desired time point by loading the cobalt bundle on the core and prevent the evaluation reprocessing and the output reduction of a neutron high output system, the method for designing a cobalt bundle of a heavy water power plant includes the steps of: designing a core loading pattern; and designing a loading pattern in order to remove the confusion of an operator by loading the cobalt bundle at a specific position in a fuel bundle. Accordingly, the present invention can easily produce Co-60.

Description

Loading pattern of Cobalt Bundle}

The present invention provides a core loading method for a cobalt bundle for minimizing the core output distribution and discharging the cobalt fuel at a desired point by loading the cobalt bundle into a core, and reducing the output and evaluation of the neutron high- The channel in which flow measurement is performed in conjunction with the stop system is expected to be influenced by the low flow trip system, so it is excluded from the cobalt bundling channel, and the peripheral channel in which the neutron high power system instrument connected with the reactor stop system is located is replaced with the cobalt- And it is designed so that there is no fluctuation of reference output. In order to prevent operator disruption by always loading a cobalt bundle at a specific position in 12 bundles, Core of bundle of cobalt designed by bundle replacement method And a loading method.

As shown in FIG. 1, the heavy water fuel is composed of 37 bars, and the whole is composed of 0.72% natural uranium of U-235.

The total number of bundles is 4560, and 12 are loaded in 380 channels. Neutron absorption is stronger than heavy water, so both coolant and moderator use critical water, and critical maintenance is required.

Conventionally, cobalt production using heavy water nuclear reactors produces Co-60 by neutron irradiation during the operation of the reactor by charging Co-59 isotopes into the control rods introduced into the reactor during normal reactor operation.

When Co-59 is neutron irradiated in a heavy water reactor, Co-60 is produced, which is used as industrial sterilized isotopes.

The cobalt core charged in the form of a cobalt core (pencil) is drawn out of the control rod during the maintenance of the reactor and is taken out of the charged cobalt core, and the worker is exposed to radiation during the process.

Insertion and withdrawal of the control rods are possible only at a fixed time, such as reactor maintenance period, and are not fluid at the date of cobalt production.

In the heavy fuel bundle, uranium dioxide is charged in the form of pellets in 37 fuel rods, and the fuel bundles are loaded into 380 fuel channels as shown in Fig.

Periodically, the fuel bundles are changed daily or weekly.

In the case of domestic heavy water fuel bundle replacement, 8 bundles are replaced in one channel having 12 bundle positions, and fuel bundles in positions 1 ~ 4 are moved to positions 9 ~ 12 when the fuel is replaced and burned twice until next fuel replacement.

Related Japanese Patent Laid-Open Publication No. 2011-7733 discloses a gamma-ray and neutron beam irradiating apparatus. Japanese Laid-Open Patent Publication No. 2013-140136 discloses a method of converting a material of an isotope into neutrons The present invention is designed such that the reference output of the reactor does not fluctuate and the cobalt bundle is always loaded at a specific position in the 12 bundles, There is a problem in that the cobalt bundle is designed to be replaced by a twelve-bundle replacement method instead of the existing 8-bundle replacement method, so that the difficulty of construction is remarkable compared with the prior arts, Compared with 1,2, there is a significant difference in composition and action effect.

The problem to be solved by the present invention is that when a cobalt bundle is injected into a bundle of heavy water reactor fuel as in a bundle of cobalt fuel in a heavy water power plant, neutrons are irradiated in a heavy water reactor so that Co-59 is modified into Co-60 to facilitate production of Co-60 have.

In addition, the present invention is advantageous in the production of Co-60 isotopes such that the production process of the cobalt produced is simple while the risk of exposing the workers to radioactivity is reduced while maintaining the core power distribution as before.

The method of the present invention includes a step of designing a pattern for loading a cobalt bundle of a heavy water power plant in a core so that there is no fluctuation in reference output, Designing a core loading pattern so as not to re-execute the reduction and evaluation of the output of the neutron high-power system, minimizing the core output distribution for utilization, and designing the loading pattern so that the cobalt bundle is loaded at a specific position in the fuel bundle, The method comprising the steps of: providing a cobalt bundle of a heavy water power plant;

As a solution to the other problem of the present invention, the specific position is to fix the second and eleventh bundles in the channel of 12 fuel bundles in order to simplify the drawing process of the produced cobalt Co-60 and reduce the risk of exposure to radioactivity by workers. And a method of loading a core of a cobalt bundle of a heavy water power plant.

Another object of the present invention is to provide a cobalt bundle of a heavy water power plant including a step of designing a corresponding channel fuel replacement method to be a twelve bundle replacement method so that a cobalt bundle is always loaded at a specific position, And to provide a core loading method.

As another means for solving the problem of the present invention, the cobalt bundle modified by cobalt Co-60 in the cobalt Co-59 loaded at a specific position in the 12 bundles includes a step of releasing the cobalt bundle in the same route as the spent fuel And a method for loading a core of a cobalt bundle.

The present invention relates to a method for designing a cobalt bundle of a heavy water plant, wherein a cobalt bundle (Co-59) of a heavy water plant is injected into a bundle of heavy water reactor fuel and neutron irradiation is performed in a heavy water reactor, There is an advantageous effect that it can be easily produced.

In addition, the present invention has an advantageous effect for production of Co-60 isotope such that the production process of the cobalt produced is simple while the risk of exposing the worker to radiation is reduced while maintaining the core power distribution as before.

1 shows a state in which a heavy water fuel is loaded in a channel.
2 shows the channel output effect evaluation 1) for the cobalt bundle loading channel pattern (E03 / E20 / S03 / S20) in the core. (Error = (normal bundle-cobalt bundle) / normal bundle * 100 (% )
Figure 3 shows the channel output effect evaluation for the cobalt bundle loading channel pattern (B06 / B17 / V06 / V17) in the core (error = (normal bundle - cobalt bundle) / normal bundle * 100 (%)).
Figure 4 shows a cobalt bundle loading scheme in a channel.

Hereinafter, the present invention will be described in detail.

It is a method of neutron irradiation inside the reactor to reduce the radiation exposure time of the worker and to produce the same amount of cobalt isotope.

The cobalt charge bundle discharged in a fuel replacement manner is configured to be located in the spent fuel reservoir through the same path as the spent fuel.

The cobalt charge bundle in the spent fuel storage tank is transported to a Co-60 processing facility produced safely in a shielded container. The process of withdrawing the cobalt produced is simple and the risk of workers being exposed to radioactivity is reduced.

A specific embodiment of the present invention will be described.

<Examples>

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will now be described with reference to the drawings.

1 shows a state in which a heavy water fuel is loaded in a channel.

2 shows the channel output effect evaluation 1) for the cobalt bundle loading channel pattern (E03 / E20 / S03 / S20) in the core. (Error = (normal bundle-cobalt bundle) / normal bundle * 100 (% )

Figure 3 shows the channel output effect evaluation for the cobalt bundle loading channel pattern (B06 / B17 / V06 / V17) in the core (error = (normal bundle - cobalt bundle) / normal bundle * 100 (%)).

Figure 4 shows a cobalt bundle loading scheme in a channel.

The present invention is a method for producing cobalt Co-60 using a heavy water reactor.

The present invention is to load a cobalt bundle loaded with cobalt into neutron irradiation in Co-59 in a reactor until it is loaded in place of a bundle of fuel loaded with uranium dioxide and discharged by fuel replacement.

In order to prevent operator disruption in loading the cobalt bundle into the core, the second and eleventh bundles in the channel are fixed and installed in the channel as shown in FIG. 4, so that the process of withdrawing the cobalt produced is simple, It can reduce the risk.

In order to prevent cobalt-loaded fuel bundles from harming the design output and reactor safety, the operation restrictions of the power plant should be examined.

In order to maintain the design output of the heavy water reactor core, the replacement of the heavy fuel bundle is selected by the plant core manager considering the core power distribution of the reactor to determine the replacement channel.

It is desirable to exclude the channel from the loading channel because the channel with the flow measurement connected to the reactor stop system is expected to affect the low flow trip system.

The peripheral channel in which the neutron high-power system instrument connected with the reactor stop system is located is preferable to design the core fill-in pattern as shown in FIGS. 2 and 3, since it may cause a temporary over-output signal when the bundle of cobalt- Do.

It is desirable to design the fill pattern as shown in FIG. 4 so that there is no fluctuation of the reference output when designing the core fill-in pattern and the cobalt bundle is loaded at a specific position in 12 bundles to avoid operator confusion.

It is desirable to design the channel fuel replacement method so that the 12-bundle replacement method is used instead of the 8-bundle replacement method used in order to prevent operator confusion by always loading the cobalt bundle at a specific position in the bundle 12.

The technical construction of the core loading method of the cobalt bundle according to the present invention will be described in more detail.

The cobalt bundle is loaded into the core to discharge the cobalt fuel at a desired point, minimizing the core output distribution for transportation and utilization, and designing the core fill-in pattern as shown in FIGS. 2 and 3 in order not to re- duce the output of the neutron high- .

And designing such that there is no reference output fluctuation in designing the core fill-in pattern.

And a step of designing the loading pattern as shown in FIG. 4 so that the cobalt bundle is loaded at a specific position in the bundle 12 so that operator confusion is avoided.

The specific position includes a step of fixing the second and eleventh bundles in the twelve bundles in order to simplify the process of drawing the produced cobalt Co-60 and reduce the risk that the worker is exposed to radioactivity.

In order to prevent operator disruption by always loading the cobalt bundle at a specific position in the twelve bundles as described above, the corresponding channel fuel replacement method is designed to be a twelve bundle replacement method instead of the conventional eight bundle replacement method.

12 bundle of cobalt Co-60 produced at a specific location in the bundle is placed in the spent fuel storage tank through the same path as the discharged spent fuel in the fuel replacement mode.

That is, the present invention includes a step of designing a pattern for loading a cobalt bundle in a core of a heavy water power plant so that there is no reference output fluctuation. The cobalt bundle is loaded in the core to discharge a cobalt bundle at a desired point, , Designing the core loading pattern so as not to re-execute the neutron high power system output reduction and evaluation, and designing the loading pattern so that the cobalt bundle is loaded at a specific position in the fuel bundle, .

Also, the present invention includes a step of fixing the second and eleventh bundles in the channel of twelve fuel bundles in order to simplify the drawing process of the produced cobalt Co-60 and reduce the risk of exposure of the operator to radioactivity.

The present invention includes a step of designing the corresponding channel fuel replacement method to be a twelve-part replacement method so that the cobalt bundle is always loaded at a specific position and there is no operator confusion.

The cobalt bundle modified from cobalt Co-59 to cobalt Co-60 in a specific position in the 12 bundles according to the present invention includes a step of releasing the cobalt bundle modified in the same route as the spent fuel.

The method of the present invention includes a step of designing a pattern for loading a cobalt bundle of a heavy water power plant in a core so that there is no fluctuation in reference output, Designing a core loading pattern so as not to re-execute the reduction and evaluation of the output of the neutron high-power system, minimizing the core output distribution for utilization, and designing the loading pattern so that the cobalt bundle is loaded at a specific position in the fuel bundle, The present invention provides a core loading method of a cobalt bundle of a heavy water power plant including the step of preparing a Co-60 isotope, and thus the Co-60 isotope can be produced more easily.

Claims (4)

In a core loading method of a cobalt bundle of a heavy water power plant,
And designing a pattern for loading the cobalt bundle of the heavy water power plant in the core so that there is no fluctuation in the reference output,
A step of designing a core filler pattern so as to minimize the core output distribution for discharging the cobalt bundle at a desired time point by loading the cobalt bundle into the core and to reduce the power output of the neutron high power system and to re-evaluate the system; And
And designing a loading pattern so that a cobalt bundle is loaded at a specific location in the fuel bundle to avoid operator disruption. The method according to claim 1,
The specific location includes a step of fixing the second and eleventh bundles in the channel of twelve fuel bundles in order to simplify the withdrawal process of the produced cobalt Co-60 and reduce the risk of exposure of the operator to radioactivity, Of the cobalt bundle. The method according to claim 1,
Comprising the step of designing the corresponding channel fuel replacement method to be a twelve bundle replacement method in order to prevent operator disruption by always loading a cobalt bundle at a specific location. The method of claim 3,
12. A core loading method of a cobalt bundle in a heavy water plant, comprising the step of loading a cobalt bundle modified with cobalt Co-60 from cobalt Co-59 at a specific location in a bundle, in the same fuel path as the spent fuel.

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