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- From: harrisp@wl.aecl.ca
- Newsgroups: comp.ai.neural-nets
- Subject: Advice re suitabilty of ANN's for this application
- Message-ID: <14AUG92.09433373@wl.aecl.ca>
- Date: 14 Aug 92 15:43:33 GMT
- Sender: news@cu23.crl.aecl.ca (USENET News System)
- Organization: AECL RESEARCH
- Lines: 81
- Nntp-Posting-Host: wc4.wl.aecl.ca
-
-
-
- We are trying to determine if the following problem is one which is suitable
- for addressing with a neural network. If so, what sort of network would be
- "best" to use? Any advice re: software to use, implementation and testing
- of the system, relevant literature etc would be greatly appreciated.
-
- The problem may be stated as follows:
-
- In a nuclear power reactor, a wide variety of chemical processes may occur in
- the water used both in the boiler and the steam side of the heat transport
- system. Important chemical parameters to be monitorred include the pH,
- conductivity, dissolved hydrazine, dissolved oxygen, and particulate
- concentrations. Often, transient conditions occur, during changes in reactor
- power, which lead to sudden changes in the water chemistry.
- These chemical processes can lead corrosion and the formation
- of "crud", leading to boiler fouling. This in turn leads to lost revenue
- due to derating, shutdown, cleaning and replacement of components.
-
- Monitorring of the chemistry has been in progress for a number of years,
- primarily through the acquisition and analysis of grab samples, although more
- online monitoring is being included as time progresses. The reactor
- operators are required to monitor the chemistry in the heat transport
- systems, to attempt to identify when an undesirable event is likely to
- occur, and to take preventive measures to minimize damage and lost revenue.
- The process of trying to assimilate the large amounts of data, and to
- qualitatively determine whether this will lead to an undesirable event, is
- of course quite difficult.
-
- We have as data (for a potential training set) the chemistry related data
- from before, after and during a number of "events". Also included in the
- data sets is the efforts taken by the operators to deal with the event,
- and info on what caused the event to happen. Two approaches have
- been proposed to make use of this data. One is to develop a mechanistic
- model based on the chemical reaction kinetics of the species and surfaces
- present in the system. This model could then be used to determine the
- conditions under which fouling is likely to occur. The second approach would
- be to use a non-mechanistic approach, such as an Artificial Neural Network,
- which would be trained, using the data described previously, in such a way
- that the data for the "current" measurements, and perhaps some information
- from "past" measurements, could be used as input to the network, and the
- network would provide as output:
-
- a) Problem / No Problem (minimal information needed)
-
- This would be what we would consider successful, but not
- very satisfactory solution to the problem
-
- b) Problem Identification (ie there is a problem due to the combined
- effects of high dissolved oxygen and
- low pH {this type of information to
- have been obtained from the training
- sets} )
-
- This would be both successful and satisfactory if achieved.
-
- c) Problem Identification and/or Solution Proposal
-
- (ie. the network identifies the problem and proposes
- a method, based on past experience, for resolution
- of the problem)
-
- This would be the ideal solution to the problem.
-
- The main desire in this program is provide an automated method for dealing
- with the data to minimize the need of the reactor operators to concern
- themselves with the chemistry of the heat transport loop, and focus even
- more of there attention of reactor operating conditions and safety (which is
- already there primary responsibility, they would prefer not to have to worry
- to much about the chemistry end of the heat transport)
-
- An expert system approach has been attempted by others for solving this
- problem, but it apparently didn't meet with much success. Hard to get much
- info about it, as it was done under a proprietary research contract to an
- electrical utility.
-
- ANY ADVICE/SUGGESTIONS/INFORMATION re the feasibility of this project
- would be greatly appreciated.
-
- Thanks in advance
- Phil Harris
-