Let our YBCO superconductor have the formula YBa2Cu3O7. Then the reaction with hydrochloric acid solution proceeds according to the following equation:
YBa2Cu3O7 + 13HCl → YCl3 + 2BaCl2 + 3CuCl2 + 6.5H2O + O2.
This and some other reactions of YBCO superconductor are described in the follow NASA...