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Title: ORCHID - a computer simulation of the reliability of an NDE inspection system

Abstract

CANDU pressurized heavy water reactors contain several hundred horizontally-mounted zirconium alloy pressure tubes. Following a pressure tube failure, a pressure tube inspection system called CIGARette was rapidly designed, manufactured and put in operation. Defects called hydride blisters were found to be the cause of the failure, and were detected using a combination of eddy current and ultrasonic scans. A number of improvements were made to CIGARette during the inspection period. The ORCHID computer program models the operation of the delivery system, eddy current and ultrasonic systems by imitating the on-reactor decision-making procedure. ORCHID predicts that during the early stage of development, less than one blistered tube in three would be detected, while less than one in two would be detected in the middle development stage. However, ORCHID predicts that during the late development stage, probability of detection will be over 90%, primarily due to the inclusion of axial ultrasonic scans (a procedural modification). Rotational and axial slip could severely reduce probability of detection. Comparison of CIGARette's inspection data with ORCHID's predictions indicate that the latter are compatible with the actual inspection results, through the numbers are small and data uncertain. It should be emphasized that the CIGARette system has beenmore » essentially replaced with the much more reliable CIGAR system.« less

Authors:
Publication Date:
Research Org.:
Ontario Hydro Research Division, Toronto
OSTI Identifier:
5857209
Resource Type:
Journal Article
Journal Name:
J. Nondestr. Eval.; (United States)
Additional Journal Information:
Journal Volume: 6:1
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 36 MATERIALS SCIENCE; BLISTERS; DETECTION; CANDU TYPE REACTORS; INSPECTION; PRESSURE TUBES; EDDY CURRENT TESTING; FAILURES; ULTRASONIC TESTING; TEST FACILITIES; O CODES; RELIABILITY; SYSTEMS ANALYSIS; ZIRCONIUM ALLOYS; COMPUTERIZED SIMULATION; HYDRIDATION; HYDROGEN EMBRITTLEMENT; PROBABILITY; ACOUSTIC TESTING; ALLOYS; CHEMICAL REACTIONS; COMPUTER CODES; ELECTROMAGNETIC TESTING; EMBRITTLEMENT; HEAVY WATER MODERATED REACTORS; MATERIALS TESTING; NONDESTRUCTIVE TESTING; PRESSURE TUBE REACTORS; REACTORS; SIMULATION; TESTING; THERMAL REACTORS; TUBES; 210400* - Power Reactors, Nonbreeding, Otherwise Moderated or Unmoderated; 360105 - Metals & Alloys- Corrosion & Erosion; 360103 - Metals & Alloys- Mechanical Properties

Citation Formats

Moles, M.D.C. ORCHID - a computer simulation of the reliability of an NDE inspection system. United States: N. p., 1987. Web. doi:10.1007/BF00566694.
Moles, M.D.C. ORCHID - a computer simulation of the reliability of an NDE inspection system. United States. doi:10.1007/BF00566694.
Moles, M.D.C. Sun . "ORCHID - a computer simulation of the reliability of an NDE inspection system". United States. doi:10.1007/BF00566694.
@article{osti_5857209,
title = {ORCHID - a computer simulation of the reliability of an NDE inspection system},
author = {Moles, M.D.C.},
abstractNote = {CANDU pressurized heavy water reactors contain several hundred horizontally-mounted zirconium alloy pressure tubes. Following a pressure tube failure, a pressure tube inspection system called CIGARette was rapidly designed, manufactured and put in operation. Defects called hydride blisters were found to be the cause of the failure, and were detected using a combination of eddy current and ultrasonic scans. A number of improvements were made to CIGARette during the inspection period. The ORCHID computer program models the operation of the delivery system, eddy current and ultrasonic systems by imitating the on-reactor decision-making procedure. ORCHID predicts that during the early stage of development, less than one blistered tube in three would be detected, while less than one in two would be detected in the middle development stage. However, ORCHID predicts that during the late development stage, probability of detection will be over 90%, primarily due to the inclusion of axial ultrasonic scans (a procedural modification). Rotational and axial slip could severely reduce probability of detection. Comparison of CIGARette's inspection data with ORCHID's predictions indicate that the latter are compatible with the actual inspection results, through the numbers are small and data uncertain. It should be emphasized that the CIGARette system has been essentially replaced with the much more reliable CIGAR system.},
doi = {10.1007/BF00566694},
journal = {J. Nondestr. Eval.; (United States)},
number = ,
volume = 6:1,
place = {United States},
year = {1987},
month = {3}
}