Spurious signals in instrumentation cables


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A Nuclear Power Plant is almost commissioned. Trial was conducted before making the reactor to reach criticality. However, spurious signal/noise was observed in the instrumentation cables. It was to that extent that the DCS gets tripped because of the high level of noise in the instrumentation cable. What will be the possible source of noise? How this can be overcome?

One of the known facts is that the control system documentation came late. The instrumentation cables were not laid earlier and taken out properly before the Reactor pressure vessel containment structures were made. The reactor pressure vessels containment structure was later cut open to lay the instrumentation and control cables. At this juncture, the Instrumentation and power cables were laid in the same tray. However, in spite of no power production, spurious signals / noise is there in the instrumentation cables. Please give details about the probable cause of spurious signals to this magnitude.

Thanking you in advance.

<b>Moderator's note:</b> poster does not give any info about the country he is from. Almost told him to contact the United Nations Nuclear Regulatory Commission.
Well, youve already told us what the problem is - you laid signal cables in the same tray as power cables. Any other suggestions we can give you would be pure speculation.

At this point you appear to have a very serious problem. If what you have told us is correct then your plant control system could have significant reliability problems for its entire operating life. Given that this particular type of plant needs very high reliability, then you're in trouble.

I think you probably need to get an independent expert on site now to do a full investigation.
Energy... US Nuclear plants do not use a DCS to control the Nuclear-side of such plants!

However, if you want to learn how Nuclear Plant Availability in the US can be increased by at least 100 hours per year, then obtain a copy of the report:

Electrical Power Research Institute (EPRI)Report # NP-5416, Project 2641-1, "Turbine Protection System Evaluation"!

Regards, Phil Corso