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197° io-® 
Mox. Permissible Level (uc/cm>) 
FIG. 1. Leaktightness re- 
quirements of primary 
coolant system for 107-ft? 
building with 5,000-ft3/min 
ventilation 
107 
Nuclear-Plant Leaktightness 
By J. P. VERKAMP and S. L. WILLIAMS 
Knolls Atomic Power Laboratory,* General Electric Company, Schenectady, New York 
LEAKTIGHTNESS PROGRAM SHOULD INCLUDE: 
@ Determination of how extensive a program can be justified 
@ Design of components and connections for cleaning and inspecting facility, 
minimum-size welds, and convenient-size subassemblies 
@ Enforceable cleanliness and inspection program 
@  Leaktightness requirements in all component specifications and all subas- 
sembly work; sequence operations to permit several rechecks of leak-sus- 
ceptible components 
@ Extra care to insure sound welds in component and subassembly work and 
final system assembly 
@ Integration and sequencing of over-all fabrication, inspection, testing, and 
assembly work 
ALTHOUGH LEAKAGE CONTROL has been 
an important consideration in engineer- 
ing and constructing remote nuclear 
power plants, greater emphasis on 
leaktightness will be necessary for 
plants located in populated areas. 
Since the use of sewers, streams, or the 
atmosphere for dissipating leakage and 
medical surveillance of the local popu- 
* Operated for the U. S. Atomic Energy 
Commission by the General Electric Co. 
114 
lation are impractical, a leaktightness 
program must be instituted covering 
design, fabrication, and final assembly 
of the plant. 
Design 
In designing piping for nuclear 
plants, particular attention should be 
paid to selecting components that will 
minimize leaks. For example, socket 
weld fittings have been used on small 
piping as a general construction prac- 
tice to facilitate field assembly. But 
welding these fittings to obtain leak- 
tight joints is frequently difficult, and 
the fittings do not lend themselves to 
radiographic testing after installation. 
Early pressurized-water systems re- 
quired a number of auxiliary systems 
composed of numerous small pipe con- 
nections. Here, careful selection of 
