Page 8 - SRNS_Today_May_2021
P. 8

8   |   SRNS TODAY   | MAY 2021

                           SRNL’s Kevin Counts attaches extensions to a camera rig to lower
                           into the mock-up test bed as SRNL’s Lisa Ward looks on.

                         Through the lens

                         A new approach for assessing

                          spent nuclear fuel containers

                       F      or the first time, SRNS recently completed visual examinations of non-aluminum
                              clad spent nuclear fuel (SNF) bundles stored in the L Disassembly Basin using
                              underwater cameras, which helped to ensure the integrity of the underwater
                        storage systems for this fuel for an extended storage time.
                        Most SNF stored in L Basin is covered, or clad, in aluminum and then placed in aluminum
                        bundles. However, a small portion of the fuel in L Basin is housed in aluminum bundles
                        but clad in either zirconium alloy (zircaloy) or stainless steel.
                        “We needed a way to inspect the aluminum bundles that house non-aluminum clad
                        spent nuclear fuel to make sure galvanic corrosion wasn’t occurring,” SRNS Augmented
                        Monitoring and Condition Assessment Program (AMCAP) Manager Michelle Hromyak
                        said. “Galvanic corrosion happens when two metals that are dissimilar in nature, in this
                        case the aluminum bundles and the zircaloy or stainless steel clad spent nuclear fuel, are
                        closely coupled underwater and one metal corrodes the other.”
                        AMCAP is a spent fuel program that provides non-destructive examination capabilities to
                        aid extended safe storage of the SNF until its final disposition.
                        The cameras were specially selected, and tooling was designed in conjunction with SRNL
                        to withstand the radiochemistry of the water while being submerged approximately 30
                        feet into L Basin.
                        In advance of the examinations, SRNL and SRNS developed a mock-up to test the
                        cameras and the accompanying long-handled tools specially developed to accomplish the
                        fuel bundle visual examinations.
                        “Over the next few years, we plan to continue visual examinations to ensure fuel integrity,”
                        Hromyak said. “With SRNL’s help, we are also developing ultrasonic testing capability to
                        validate the integrity of the fuel inside the bundles and determine if any worsening storage
                        conditions are occurring that we cannot see with just visual examinations.”
   3   4   5   6   7   8   9   10   11   12   13