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ALARA

ALARA. As Low As is Reasonably Achievable. Enabling Objectives - 1. Define ALARA & Describe Concepts Explain Stochastic & Nonstochastic Effects & Describe Differences State Aim of ALARA & How Achieved Identify Regulatory Basis for ALARA Define “Acceptable” and “Total” Risk

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ALARA

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  1. ALARA As Low As is Reasonably Achievable TVAN Technical Training Health Physics (RADCON) Initial Training Program

  2. Enabling Objectives - 1 • Define ALARA & Describe Concepts • Explain Stochastic & Nonstochastic Effects & Describe Differences • State Aim of ALARA & How Achieved • Identify Regulatory Basis for ALARA • Define “Acceptable” and “Total” Risk • Responsibilities for Implementing ALARA TVAN Technical Training Health Physics (RADCON) Initial Training Program

  3. Enabling Objectives - 2 • Identify the ALARA Committee and Functions • State the ALARA Goal Setting Process • State Criteria for ALARA Planning Report & Post-Job Report • Identify Responsibilities for the Annual ALARA Report • Identify Six Items in the Pre-Job Brief TVAN Technical Training Health Physics (RADCON) Initial Training Program

  4. Enabling Objectives - 3 • State Means to Reduce Cobalt • Identify the Desired Type of Control • List Four Exposure Reduction Techniques • Identify Regulatory Basis for Change Evaluations • State two Consequences of Removing Shielding Without Approvals TVAN Technical Training Health Physics (RADCON) Initial Training Program

  5. Radiation Protection Radiation Protection is concerned with the protection of Individuals, their Progeny and Mankind as a whole, while still allowing necessary activities from which radiation exposure might result. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  6. Purpose of ALARA Minimize Risk as a Result of Exposure to Radiation or Radioactive Material to Employees and the Public to a Level that is As Low As is Reasonably Achievable (ALARA) TVAN Technical Training Health Physics (RADCON) Initial Training Program

  7. ALARA • Make Every Reasonable Effort • Maintain Radiation Exposures as far Below the Dose Limits as is Practical • Consistent with Purpose of Licensed Activity • Consider State of Technology and Economics vs. Benefits Provided TVAN Technical Training Health Physics (RADCON) Initial Training Program

  8. ALARA Goal • Maintain ALL Exposures ALARA - Individual Exposures – Rem - Collective Exposures – Sum of Doses received by all exposed Individuals – Man-rem Don’t reduce individual exposure at the expense of population exposure. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  9. Acute & Chronic Doses Acute Radiation Dose – A relatively large dose of Radiation received in a short period of time. Chronic Radiation Dose – The sum of small radiation doses received repeatedly over long periods of time. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  10. Nonstochastic Health Effects • Health Effects, the severity of which varies with the dose and for which a threshold is believed to exist.Example - Radiation-Induced cataract formation TVAN Technical Training Health Physics (RADCON) Initial Training Program

  11. Stochastic Health Effects • Health Effects that occur randomly and for which the probability of the effect occurring, rather than its severity, is assumed to be a linear function of dose without threshold.Examples – Hereditary effects and cancer incidence. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  12. Aim of Radiation Protection • Prevent detrimental nonstochastic effects and limit the probability of stochastic effects to levels deemed acceptable. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  13. To Achieve Aim: (1) • Nonstochastic Effects – Set dose limits at sufficiently low values so that no threshold dose would be reached. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  14. To Achieve Aim: (2) • Stochastic Effects – Keep all justifiable exposures as low as is reasonably achievable, taking into account economic and social factors and ensuring that appropriate dose equivalent limits are not exceeded. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  15. Basis for ALARA • Regulation: 10CFR20.1101 “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 general public that are as low as is reasonably achievable (ALARA).” TVAN Technical Training Health Physics (RADCON) Initial Training Program

  16. Guidelines for ALARA • Regulatory Guides:- RG 8.8, Maintaining exposures at nuclear power stations ALARA. • - RG 8.10, Guidance for maintaining occupational exposures ALARA. - RG 8.29, Risks from occupational radiation exposures. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  17. Acceptable or Comparable Risk • The occupational dose limit for adult workers (5 rem/y), combined with the application of ALARA principles, provides a level of risk of delayed effects considered acceptable by the NRC (stochastic effects), or comparable to risks associated with other “safe” industries. (RG 8.29) TVAN Technical Training Health Physics (RADCON) Initial Training Program

  18. Total Risk Concept • In evaluating specific activities, the concept of “total” risk reduction should be considered. (RG 8.29) - Consider the sum of external and internal exposures. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  19. Total Risk Concept:Example • The use of respirators can lead to increased work time in radiation areas, which increases external doses. • The advantage of using respirators to reduce internal exposure must be evaluated against the increased external exposure. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  20. Components of ALARA • Training • Planning • Cost-Benefit Analysis • Implementation • ALARA Suggestion Program TVAN Technical Training Health Physics (RADCON) Initial Training Program

  21. Cost-Benefit Analysis • Costs: - Equipment Dollars- Labor Dollars- Risk in Dollars of exposure received • Benefits:- Dollars saved by use of ALARA- Exposure saved, Dollars Assign a value of $25,000 for each rem. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  22. Cost-Benefit Example • Proposal to add shielding to piping • Cost:- (equipment & labor) = $359,000- 8 man-rem X $25,000 = $200,000- Total cost = $559,000 • Benefit:- Reduced dose: 0.95 man-rem/month for 2 year fuel cycle = 22.8 man-rem.- Total benefit = $570,000 TVAN Technical Training Health Physics (RADCON) Initial Training Program

  23. ALARA Responsibilities - 1 • Corporate Manager, Radiological and Chemistry Services- Recommend and Document ALARA Policy • Radchem Manager- Administer site ALARA Program • Each Individual- Seek methods to save or reduce man-rem exposure. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  24. ALARA Responsibilities - 2 • RADCON staffs:- Maintain ALARA dose tracking.- Review radiation exposures.- Prepare Annual ALARA Report.- Pursue reduction of occupational radiation exposures.- Promote ALARA attitude- Implement RADCON requirements TVAN Technical Training Health Physics (RADCON) Initial Training Program

  25. ALARA Responsibilities - 3 • Each Individual should:- Seek methods to save or reduce man-rem exposure.- Comply with procedures & practices.- Report hazardous/changing condition- Minimize personal radiation exposure- Track individual dose status.- Avoid exceeding dose limits. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  26. ALARA CommitteeResponsibilities • Review effectiveness of ALARA program. • Track ALARA goals. • Review ALARA suggestions. • Review ALARA planning documents for jobs exceeding 5 man-rem TEDE. • Review exposure trends. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  27. ALARA Committee • Chaired by Site VP, Plant Manager or designee • Members from:- RADCON - Modifications- Operations - Engineering- Outage - Maintenance- Nuclear Assurance- Training TVAN Technical Training Health Physics (RADCON) Initial Training Program

  28. ALARA GoalsObjectives • Objective – Minimize TEDE. • Ensures continued awareness in radiological control. • Established by functional areas and approved by Site VPs. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  29. ALARA GoalsPurposes • Set organizational exposure goals. • Set annual station man-rem goals. • Goals for major outages or work events • Goals for routinely performed operations. • Emphasize administrative dose levels. • Incentives for improving performance. • Focus attention at all levels of ALARA. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  30. Setting ALARA Goals • Identify the task, components, sources. • Identify number of workers & time . • Review radiation survey results. • Review past history. • Develop exposure estimate. • Identify exposure reduction potential. • Establish dose/dose rate action levels. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  31. ALARA Planning Report • Form SPP-5.2.1, “Preliminary Radiological Impact/Evaluation Checklist.” • Issued when plant specific criteria met, for example when TEDE for a specific task expected to exceed 1 man-rem. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  32. Post-Job Report • Required if: - Pre-Job Report was required,- Dose exceeds estimated dose by 25 percent or greater,- TEDE exceeded 1 man-rem. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  33. Annual ALARA Report • Submitted by RADCON to Site VP • Includes:- Comparison of ALARA Results with ALARA Goals.- Comparison of ALARA Results with Results in previous years.- ALARA Goals for coming year. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  34. Pre-Job Briefing • Conducted when TEDE expected to exceed 1 man-rem. • Incorporates appropriate ALARA considerations. • Attended by all personnel directly involved in the work. • Scheduled as near as possible to start of job. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  35. Pre-Job Brief Contents -Radiological (1) • Review of applicable procedures. • Dose rates, Contamination levels, etc. • Access routes to & from work site. • Areas to be avoided. • High radiation areas & hot spots. • Location of low dose rate areas. • Special radiological limitations/controls TVAN Technical Training Health Physics (RADCON) Initial Training Program

  36. Pre-Job Brief Contents – Radiological (2) • Hold Points. • Stay Times. • Maximum dose limits. • Maximum dose rate limits. • Operating Experience/Lessons learned. • ALARA goals for the job or task. • Potential problems & contingency plan TVAN Technical Training Health Physics (RADCON) Initial Training Program

  37. Pre-Job Brief Contents – General • What are we going to do? • What is the Worst Thing that could happen? • What are the Critical Steps? • What if Mistakes happen, especially at Critical Steps? • What are the Error Likely Situations? • What are the Safety Concerns? • Operating Experiences TVAN Technical Training Health Physics (RADCON) Initial Training Program

  38. Post-Job Briefing –Radiological • Review factors affecting job performance or exposure. • Identify problems encountered. • Review radiological exposures & identify factors leading to increases or decreased from expected. • Identify corrective actions. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  39. Post Job Briefing – General (1) • Any Recommended Changes? • Any Unexpected Aspects or Occurrences? • Task Accomplished with Expected Results? • Any Enhancement to Plant Documentation Warranted? • Planning & Scheduling Optimized to Reduce Human Errors? TVAN Technical Training Health Physics (RADCON) Initial Training Program

  40. Post Job Briefing – General (2) • Was Preparation Adequate? • Lessons Learned Identified? • Needed Supervision Support Provided? • Any Human Factor Issues, Hindrances to Work Observed? • Training for Job Adequate & Effective? TVAN Technical Training Health Physics (RADCON) Initial Training Program

  41. Radiation Exposures Major portion of radiation exposures from: • Maintenance • Radwaste handling • In-Service inspections • Refueling • Nonroutine operations TVAN Technical Training Health Physics (RADCON) Initial Training Program

  42. ALARA Program Procedures • TVAN RCDP-1Sets policy to ensure risks from ionizing radiation are ALARA. • TVAN SPP-5.2Establishes ALARA Program and outlines responsibilities. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  43. ALARA Responsibilities • Senior VP, Nuclear Operations andVP, Engineering & Technical ServicesEstablish controls to incorporate: TVAN Technical Training Health Physics (RADCON) Initial Training Program

  44. VPs Establish Controls For: • Evaluate Design & Design Mods to:- Determine Radiological Impacts- Achieve Cobalt Reduction • Temporary Shielding Analysis • ALARA Walkdowns • Consider Occupational Radiation Doses TVAN Technical Training Health Physics (RADCON) Initial Training Program

  45. Design Functions • Mechanical Design StandardDS-M18.7.1 Addresses the Concept ofALARA in Plant Design Activities TVAN Technical Training Health Physics (RADCON) Initial Training Program

  46. Design Standards Include: (1) • References to Radiological Requirements of Plant Specific Restrictions or Radiological Technical Specifications. • Methods to Minimize Source Terms • Control of Fuel Integrity • ALARA Conditions of Reg Guide 8.8 • ALARA from Effluent Releases TVAN Technical Training Health Physics (RADCON) Initial Training Program

  47. Design Standards Include: (2) • Radiological Control Impacts ofDesign Changes • Radiological Impacts Regarding:- Changes in Zoning, Shielding, etc.- Source Term or Chemistry Changes- Other Systems or Adjacent Areas • Steps to Reduce Impacts of Cobalt TVAN Technical Training Health Physics (RADCON) Initial Training Program

  48. Cobalt Reduction • Use of Low Cobalt Materials for Piping and Equipment in Contact with Primary Coolant. • Eliminate Use of Cobalt-Containing Materials for Parts or Components of Valves (e.g. Valve Trim, Seats, Pins) in Flow Path to Reactor Core. TVAN Technical Training Health Physics (RADCON) Initial Training Program

  49. Impacts on ALARA - 1 • Access Control to Radiological Areas • Shielding- Labyrinth Entrances for Access- Permanent Shielding- Temporary Shielding • Instruments & Controls- Location- Remote Operation TVAN Technical Training Health Physics (RADCON) Initial Training Program

  50. Labyrinth Shielding TVAN Technical Training Health Physics (RADCON) Initial Training Program

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