Document: NUREG-0800
Document ID: 81a2e18b-7311-4c4e-822e-8dfe1b0ba7aa
Document Type: srp
Title: REACTOR PRESSURE VESSEL INTERNALS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0702/ML070230009.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.5
CFR Part: 
CFR Title: 

Content:
essure fluctuations in main steam lines) for use in confirmation of the results of any scale model testing and/or analysis for the steam dryer load definition prior to the power uprate request. 3. BWR Steam Dryer Stress and Limit Curves. After developing a steam dryer load definition, an applicant for the construction and operation of a BWR nuclear power plant and a licensee proposing a power uprate for an operating BWR nuclear power plant apply the steam dryer load definition to a stress model (usually a finite element model) of the steam dryer to determine the stress on the steam dryer with justified damping assumptions and applicable weld factors and stress intensities. Use of damping coefficients greater than 1 percent should be substantiated with measurements. After including applicable bias errors and random uncertainties, the applicant/licensee compares the peak stresses for individual steam dryer locations to the fatigue limits in the ASME Code. The applicant/licensee also compares the primary and secondary stresses on the steam dryer from plant transients to the applicable ASME Code Service Level limits. The stresses from adverse flow effects (flow-excited vibrations and acoustic resonances) should be treated as primary stresses. The BWR applicant/licensee is expected to implement any necessary modifications to the BWR steam dryer based on the design stress margins. The BWR applicant/licensee also is expected to develop a stress limit curve for power ascension for assurance that the stress in the individual steam dryer components will not exceed the ASME Code limits. 3.9.5-14 Revision 3 - March 2007 The BWR applicant/licensee develops a method that can be used for calculating the steam dryer stress, including appropriate bias errors and random uncertainties, for collecting plant data during power ascension and full licensed power conditions. As the steam dryer is not a Code component, the applicant/licensee may justify different stress acceptance criteria.