ML18120A370
| ML18120A370 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 04/30/2018 |
| From: | NRC |
| To: | NRC/NRO/DNRL/LB1 |
| References | |
| Download: ML18120A370 (5) | |
Text
NuScaleDCRaisPEm Resource From: Chowdhury, Prosanta Sent: Monday, April 30, 2018 5:28 PM To: Request for Additional Information Cc: Lee, Samuel; Cranston, Gregory; Markley, Anthony; Tesfaye, Getachew; Dudek, Michael; Lavera, Ronald; NuScaleDCRaisPEm Resource
Subject:
Request for Additional Information No. 445 eRAI No. 9255 (12.02)
Attachments: Request for Additional Information No. 445 (eRAI No. 9255).pdf Attached please find NRC staffs request for additional information (RAI) concerning review of the NuScale Design Certification Application.
Please submit your technically correct and complete response within 60 days of the date of this RAI to the NRC Document Control Desk.
If you have any questions, please contact me.
Thank you.
Prosanta Chowdhury, Project Manager Licensing Branch 1 (NuScale)
Division of New Reactor Licensing Office of New Reactors U.S. Nuclear Regulatory Commission 301-415-1647 1
Hearing Identifier: NuScale_SMR_DC_RAI_Public Email Number: 476 Mail Envelope Properties (BN7PR09MB2609B528B7D5F6E531235D7A9E820)
Subject:
Request for Additional Information No. 445 eRAI No. 9255 (12.02)
Sent Date: 4/30/2018 5:27:33 PM Received Date: 4/30/2018 5:27:38 PM From: Chowdhury, Prosanta Created By: Prosanta.Chowdhury@nrc.gov Recipients:
"Lee, Samuel" <Samuel.Lee@nrc.gov>
Tracking Status: None "Cranston, Gregory" <Gregory.Cranston@nrc.gov>
Tracking Status: None "Markley, Anthony" <Anthony.Markley@nrc.gov>
Tracking Status: None "Tesfaye, Getachew" <Getachew.Tesfaye@nrc.gov>
Tracking Status: None "Dudek, Michael" <Michael.Dudek@nrc.gov>
Tracking Status: None "Lavera, Ronald" <Ronald.LaVera@nrc.gov>
Tracking Status: None "NuScaleDCRaisPEm Resource" <NuScaleDCRaisPEm.Resource@nrc.gov>
Tracking Status: None "Request for Additional Information" <RAI@nuscalepower.com>
Tracking Status: None Post Office: BN7PR09MB2609.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 556 4/30/2018 5:27:38 PM Request for Additional Information No. 445 (eRAI No. 9255).pdf 95744 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
Request for Additional Information No. 445 (eRAI No. 9255)
Issue Date: 04/30/2018 Application
Title:
NuScale Standard Design Certification 048 Operating Company: NuScale Power, LLC Docket No.52-048 Review Section: 12.02 - Radiation Sources Application Section: 12.2 QUESTIONS 12.02-31 Regulatory Basis 10 CFR 52.47(a)(5) requires applicants to identify the kinds and quantities of radioactive materials expected to be produced in the operation and the means for controlling and limiting radiation exposures within the limits set forth in part 20.
Appendix A to Part 50General Design Criteria for Nuclear Power Plants, Criterion 61"Fuel storage and handling and radioactivity control," requires systems which may contain radioactivity to be designed with suitable shielding for radiation protection and with appropriate containment, confinement, and filtering systems.
10 CFR 52.47(a)(22) requires applicants to provided information necessary to demonstrate how operating experience insights have been incorporated into the plant design.
10 CFR 20.1101(b) states that "the licensee shall use, to the extent practical, procedures and engineering controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the public that are as low as is reasonably achievable (ALARA)." 10 CFR 20.1003 states that ALARA "means making every reasonable effort to maintain exposures to radiation as far below the dose limits in this part as is practical consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest." 10 CFR 20.1701 states that "the licensee shall use, to the extent practical, process or other engineering controls (e.g., containment, decontamination, or ventilation) to control the concentration of radioactive material in air." 10 CFR 20.1202(a) states that if the licensee is required to monitor under both 10 CFR 20.1502(a) and (b), the licensee shall demonstrate compliance with the dose limits by summing external and internal doses.
The DSRS Acceptance Criteria section of NuScale DSRS Section 12.2, "Radiation Sources,'
states that the applications should contain the methods, models, and assumptions used as the bases for all sources described in DCA Section 12.2.
Background
The radionuclide concentrations listed in DCA Subsection 12.2 are the basis of the information used to establish plant source terms. NuScale DSRS 12.2 Acceptance Criteria, states that all of
the sources of radiation exposure to workers and members of the public (from contained sources) should be identified, characterized, and considered in the design and operation of the facility. This section of the DSRS also states that unless described within other sections of the FSAR, source descriptions should include the methods, models, and assumptions used as the bases for all values provided in FSAR Section 12.2. Based on information made available to the staff during the RPAC Chapter 12 Audit, the staff was unable to identify where or how the airborne activity concentrations within the RWB were assessed.
DCA Tier 2 Revision 0, Section 12.2.2, "Airborne Radioactive Material Sources," describes the airborne radioactive material sources that form part of the basis for design of ventilation systems and personnel protective measures. DCA Section 12.2.2.1 "Reactor Building Atmosphere,"
states that airborne radioactivity may be present in the RXB atmosphere due to reactor pool evaporation or primary coolant leakage. DCA Table 12.2-33: "Reactor Building Airborne Concentrations," list the estimated airborne radionuclide concentrations for various portions of the Reactor Building (RXB). DCA Table 12.2-32: "Input Parameters for Determining Facility Airborne Concentrations," describes assumptions for calculating airborne activity within the RXB.
Alpha emitting radionuclides are radiologically significant because of their potential presence in fluids in contact with reactor fuel, and because alpha emitting radionuclides have a significantly lower Annual Limit on Intake (ALI) than beta-gamma emitting nuclides (see 10 CFR Part 20 Appendix B, Table 1.) Based on operating experience, even from plants with historically low levels of fuel defects, there is a reasonable expectation that alpha emitting radionuclides will be present in reactor coolant system fluids and the connected system components. The specific activity of the alpha emitting isotopes will increase with the amount of fuel defects present (such as operation at the Technical Specification RCS specific activity limit) and the duration of operation with even low levels of fuel defects. Electric Power Research Institute (EPRI) technical report (TR) 3002000409 Revision 2, "EPRI Alpha Monitoring Guidelines for Operating Nuclear Power Stations," (ADAMS Accession Number: ML14083A589) provides information about the significance of alpha emitting radionuclides for radiation protection. The report states that transuranic (TRU) nuclides, such as americium, plutonium and curium are formed in irradiated uranium fuel by neutron activation and decay predominantly by alpha emission. Alpha contamination most commonly associated with systems and components associated with fuel such as the reactor coolant system, spent fuel pool, and the associated radioactive waste systems. As noted in this report, the principal TRU nuclides of interest for radiation safety include curium-243/244, plutonium-238, plutonium-239/240, plutonium-241 (which decays to americium-241) and americium-241.
As noted in NUREG 1400, "Air Sampling in the Workplace," (ADAMS Accession Number:
ML13051A671) and operating experience (e.g., INPO-SER 3-93 "Contamination Events Involving Alpha-Emitting Transuranic Elements" (ADAMS Accession No. ML12228A123) and Information Notice -1997-036 "Unplanned Intakes by Workers of Transuranic Airborne Radioactive Materials and External Exposure Due to Inadequate Control of Work" (ADAMS Accession No. ML031050563)), dry radioactive material is more likely to result in significant intakes from airborne TRU alpha-emitting radionuclides.
Key Issue DCA Tier 2 Revision 0, Section 12.2.2, "Airborne Radioactive Material Sources," does not include a discussion about the sources of airborne radioactivity within the Radioactive Waste
Building (RWB). DCA Table 12.2-32, does not contain a list of assumptions relevant to the determination of airborne activity concentrations in the RWB. The RWB has a number of components and active processes that contain significant quantities of radioactive material.
Question To facilitate staff understanding of the application information in support of its reasonable assurance review regarding radiation exposures, the staff requests that the applicant:
- Revise and update Section 12.2.2 of the NuScale DCA to include a description of the airborne activity assessment for the RWB and revise and update Section 12.2.2 of the NuScale DCA to include the associated methods, models, and assumptions, used to develop the concentrations of the alpha-emitting radionuclide concentrations, x As necessary, revise DCA Table 12.2-32 to include the relevant assumptions for calculating the airborne activity concentrations in the RWB, x As necessary, revise the DCA to include a table describing the resultant estimated airborne activity concentrations, OR Provide the specific alternative approaches used and the associated justification.