Table 2: Summary of challenges

1 January 2000

	RSG Component/Assembly	Specification Requirements	Challenges	Design	Fabrication	QC
1	Channel head	Maintain thermal rating	Maintaining reactor coolant flow rate within specified limits	X	X
		Maximize number of heat transfer tubes
		Eliminate stay cylinder	Optimizing primary side volume	X
2	Tubesheet	Withstand primary-to-secondary full dP	Optimizing tubesheet thickness	X
		Limit on tube hole runout	Tubesheet drilling		X	X
		Minimize number of hole surface imperfections
3	Tube bundle	Limit on number of tube dings at time of delivery	Controlling tube bundle sag during assembly		X	X
			Monitoring temperature distribution during PWHT of the channel head-to-tubesheet weld
					X	X
4	Tube-to-tubesheet joints	Ensuring adequate tube-to tubesheet joint strength, leak resistance and corrosion resistance	Qualifying tube-to-tubesheet joint	X	X	X
			Controlling tube-to-tubesheet joint crevice depth		X	X
		Limit on allowable tube-to-tubesheet crevice depth
5	Tube supports	Preventing tube wear	Configuring tube-to-tube support interface	X
		Preventing tube denting at tube supports
6	AVB support structure	Preventing tube wear	AVB structure assembly	X	X	X
7	Feedwater distribution system	Elimination of susceptibility to water hammer and thermal stratification	Configuring inlet piping to feedwater ring	X
		Resistance to erosion/corrosion
8	Moisture separators	Limit on allowable moisture carryover	Designing moisture separator assemblies	X

Post to: