The 
reporting on the seemingly left field decision by the IOTUS to allow korean access to US nuclear power technology has suggested a viable course for the RCN (and perhaps RAN) wrt acquiring and operating SSNs.
At first glance it highlights that potentially, this could be through an adaption of the KSS-III design. While the KSS-III displaces 4,000t submerged it could be able to be redesigned for nuclear propulsion (using the existing US S9G PWR). It is a possibility as France’s 
Rubis-class SSNs displaced just 2,600t submerged, and were far shorter at 74m in length compared to the Batch 2 KSS’ 89m form.
While these potential SSNs would not be available for the next 15+ years or more it would be an advantage to the RCN to select and use the KSS-III batch 2 SSKs to maintain the silent service until they can procure the new KSS-III batch 3 SSNs. That would allow the time for the training of the operators and maintainers of nuclear powered submarines.