CS201893B1 - Method of determinating the places with reduced passability and non passable places in the sodium loops - Google Patents

Description

SUMMARY OF THE INVENTION The present invention provides a method for detecting sites of reduced patency and impassable sites in sodium loops for treating liquid sodium in nuclear power plants.

In nuclear power plants, liquid sodium is used as heat-transmitting handle. For this purpose, sodium must be in a mechanically and chemically completely pure state. After reaching chemical purity, it is treated in sodium loops, consisting of heated pressure vessels, heated pipes, cool sumps, valves of β measuring instruments. During the treatment, liquid sodium containing dissolved impurities is fed via a conduit to so-called cool sumps, where the impurities in the form of oxides are released and settled due to the reduced temperature and flow rate. Even with correctly designed loops, it may happen that the dirt starts to settle not only in cold wells, but also in some parts of piping β with a narrower cross-section and lower temperature compared to the surrounding parts of the loop. Such a ground becomes impassable after some time.

For technological reasons, there may be several of these tapered profiles on the loop, and then the problem of identifying an impassable site arises. So far, there is no other way to detect impassable milling than to progressively disassemble the portions of the loop that are most likely to be clogged, and mechanically check for continuity.

The above-mentioned drawbacks are eliminated by the method of detecting bottlenecks and impassable sites in the sodium loops according to the invention.

201 893 that in the exposed, delimited sections of the sodium loop, the electrical resistance of each of the delimited sections of the loop is grained and recorded in a fault-free state, whereby the measured electrical resistance values are compared to its resistive value will show relative to a trouble-free state relatively seen change.

The method of detecting reduced throughput and impermeable sites of the present invention allows a relatively accurate and rapid identification of such a site in the sodium loop without the need to disassemble the individual parts of the loop. In order to increase the accuracy, it is also possible to sense the temperatures of the respective sections in both the failure-free and partially or completely impassable states, and to correct the electrical resistance values at these temperatures.

The exposed sections of the sodium loop, where incrustation and subsequent blockage may occur, are delimited by electrical terminals that can be welded to the pipeline and brought to the level of the heating bendings and insulation layers of the pipeline. After putting the loop into operation, the electrical resistance of the individual sections defined by the terminals is measured. In case of blockage of the loop or probability of contamination increase in some sections, the electrical resistance of the individual sections e is measured again and the measured values are compared with the values not measured in the failure-free state. The loop section which will have the relatively greatest deviation of the electrical resistance in this comparison is impassable.

Measurement of electrical resistances of defined loop sections It is possible to carry out, for example, a bridge for measuring low resistances. For field devices, this method can be applied by appropriate wiring to automatic loop blocking.

Claims (1)

SUBJECT OF THE INVENTION A method for detecting bottlenecks and impassable sites in sodium loops, characterized by the fact that in exposed, bounded sections of the sodium loop, the electrical resistance of each of the bounded sections of the loop ripples and is recorded in a faultless state. The impermeable spot ee identifies the impassable point ee in the section in which its resistance value shows relatively the largest change compared to the failure-free state.