  A brief review is given of the integrable realization of affine fusion
discovered recently by Korff and Stroppel. They showed that the affine fusion
of the $su(n)$ Wess-Zumino-Novikov-Witten (WZNW) conformal field theories
appears in a simple integrable system known as the phase model. The Yang-Baxter
equation leads to the construction of commuting operators as Schur polynomials,
with noncommuting hopping operators as arguments. The algebraic Bethe ansatz
diagonalizes them, revealing a connection to the modular S matrix and fusion of
the $su(n)$ WZNW model. The noncommutative Schur polynomials play roles similar
to those of the primary field operators in the corresponding WZNW model. In
particular, their 3-point functions are the $su(n)$ fusion multiplicities. We
show here how the new phase model realization of affine fusion makes obvious
the existence of threshold levels, and how it accommodates higher-genus fusion.
