This paper describes preparing mockup tubesheet specimens for visual examination using a digital microscope to determine that tube-to-tubesheet joint welds are of the specified size and that expanded joints are satisfactory for the intended purpose. It discusses nondestructive examinations (NDE) of the tubesheets and tube joints intended to assure achieving sufficient tightness and strength to satisfy the uses to which the exchangers will be put. This paper refers to the ASME Boiler and Pressure Vessel Code (Code) paragraphs that apply to tube joint welds and expanded joints including shear load testing when the Code requires it [1]. The discussion also addresses the need for manufacturers to have qualified tube joining procedures and personnel qualified to use the qualified procedures. The work concludes with a summary of ways to assure tube joint tightness and strength.

References

References
1.
The ASME Boiler and Pressure Vessel Code, The American Society of Mechanical Engineers, New York. The current edition of the Code is the 2011 edition. The Code is published at two-year intervals
.
2.
Standard for Power Plant Heat Exchangers
,
4th ed.
,
2004
,
The Heat Exchange Institute
,
Cleveland, OH
.
3.
Standards of the Tubular Exchanger Manufacturers Association
,
9th ed.
,
2007
,
The Tubular Exchanger Manufacturers Association
,
Tarrytown, NY
.
4.
Standards for Closed Feedwater Heaters
,
8th ed.
,
2008
,
The Heat Exchange Institute
,
Cleveland, OH
.
5.
Directive 97/23/EC of the European Parliament
.
6.
Yokell
,
S.
,
2007
, “
Hybrid Expansion Revisited
,”
ASME J. Pressure Vessel Technol.
,
129
,
pp.
482
487
.
7.
Yokell
,
S.
,
2011
, “
Pressure Testing Feedwater Heaters and Power Plant Auxiliary Heat Exchangers
,”
ASME J. Pressure Vessel Technol.
,
133
,
054502
.
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