Tube support effectiveness and wear damage assessment in the U-bend region of nuclear steam generators
- Atomic Energy of Canada Limited, Chalk River, Ontario (Canada). Chalk River Labs.
Damage mechanisms such as fretting-wear and fatigue have resulted in substantial long-term problems in nuclear steam generators (SGs). These damage mechanisms must be better understood in order to improve the design for future SGs and limit the damage occurring in existing SGs. In the U-bend region of these heat exchangers, tube vibration is caused by two-phase cross flow. An experimental program has been developed to simulate two-phase cross flow in the U-bend region. The effectiveness of U-bend tube restraints is studied by monitoring the tube vibration and the tube-to-support contact during single- and two-phase cross flow. Work-rate is a measurement of the contact criteria that combines both contact force and sliding distance. The work-rate is directly related to the wear rate between the tube and support. Effectiveness of the tube supports in the in-plane and out-of-plane directions was studied by examining tube response and the resultant work-rates for two different tube-to-support clearances. U-bend tube restraints limit the out-of-plane tube motion to the magnitude of the tube-to-support clearance while in-plane motion continues to increase with flow rate. Surprisingly, tube-to-support work-rates for two-phase cross flow did not increase with pitch velocities greater than approximately 2 m/s. Tube eccentricity within the support clearance also proved to be a significant factor in the measured work-rate and therefore the resulting tube-to-support wear.
- OSTI ID:
- 403400
- Report Number(s):
- CONF-960706-; ISBN 0-7918-1775-X; TRN: 97:000269
- Resource Relation:
- Conference: American Society of Mechanical Engineers (ASME) pressure vessels and piping conference, Montreal (Canada), 21-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Flow-induced vibration -- 1996. PVP-Volume 328; Pettigrew, M.J. [ed.] [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]; Paidoussis, M.P. [ed.] [McGill Univ., Montreal, Quebec (Canada)]; Weaver, D.S. [ed.] [McMaster Univ., Hamilton, Ontario (Canada)]; Au-Yang, M.K. [ed.] [Framatome Technologies, Lynchburg, VA (United States)]; PB: 498 p.
- Country of Publication:
- United States
- Language:
- English
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