This interim progress report evaluates existing data on HWC effects on shutdown radiation fields. Recommendations are made on mitigation techniques that could be employed immediately, future plant and laboratory work to identify the role of key variables, mechanisms of phenomenon, and potential mitigation techniques worthy of further development.
This document provides an interim report on the progress of Project RP1930-7, BWR Hydrogen Water Chemistry - Chemical Surveillance. It describes the work performed at Commonwealth Edison's Dresden Nuclear Power Station Unit 2 during its first full fuel cycle on Hydrogen Water Chemistry to monitor its chemical and radiological performance. It includes the results of gamma scan/dose rate campaigns, ion chromatography, and other extensive water chemistry measurements. Also reported are findings and recommendations regarding plant operational practices and offgas fires. This experience at Dresden-2 has demonstrated that a plant can operate on Hydrogen Water Chemistry with only minor impact on plant parameters, but with a major positive impact on intergranular stress corrosion cracking (IGSCC) mitigation for sensitized stainless steel components.
With GEZIP (Gneneral Electric Zinc Injection Passivation), zinc is injected into reactor cooling water in order to control the build up of radiation fields. The technique was used for the first fuel cycle at Hope Creek and - following tests to confirm the absence of adverse effects in a mature reactor - at Millstone 1.
This report covers work on the BWR Radiation Assessment and Control (BRAC) Program from 1978 to 1982. The major activities during this report period were assessment of the radiation-level trends in BWRs, evaluation of the effects of forward-pumped heater drains on BWR water quality, installation and operation of a corrosion-product deposition loop in an operating BWR, and analyzation of fuel deposit samples from two BWRs. Radiation fields were found to be controlled by cobalt-60 and to vary from as low as 50 mr/h to as high as 800 mr/h on the recirculation system piping. Detailed information on BWR corrosion films and system deposits is presented in the report. Additionally, the results of an oxygen injection experiment and recontamination monitoring studies are provided.
This report provides the status of zinc addition to the boiling water reactor (BVM) for the purpose of controlling shutdown dose rates in the primary system. For the thirteen plants which have reported results thus far, the most recent average contact dose rate at the standard comparison locations is 135 mR/h. The historical averages at these locations in non-zinc BWRs has been approximately 350 mR/h. The other impacts of zinc additions on BWR chemistry, fuel performance and IGSCC mitigation are discussed. The report concludes that the use of zinc addition has successfully lowered dose rates and recommends broader industry implementation.
