Actually we both screwed up by a factor of 1000, the article states 190 becquerels of tritium per litre, not cubic meter.

Seems like you have the right order of magnitude, but the sources I've seen gives the ocean close to 0.5-2 TU, or "Tritium Units" which correspond to 180 Bq/m^3. So I wouldn't call the water being released as cleaner, just basically on average with the ocean already.

https://www.ldeo.columbia.edu/res/fac/etg.tmp/text/woce_method.html https://www.sciencedirect.com/science/article/pii/S0048969718348034