Non-Radiation Worker Training

Non-Radiation Worker Non-Radiation Workers (NRW) at NPS are those individuals who do not meet the regulatory definition of Radiation Worker (e.g. >500 mrem/yr) but may still be exposed to ionizing radiation during the performance of their duties. Analytical measurement instrument operators (SEM, TEM and XRD) Sabre 4000 operators Firefighters, medical and security personnel

Training Requirements NRW training is required by: NAVSEA S0420-AA-RAD-010 (RAD-10), Radiological Affairs Support Program Manual NAVPGSCOL INST 6470.1G, Radiation Safety Program for Naval Postgraduate School RAD-010 and 6470.1G contain the topics covered in this training Standard and Emergency Operating Procedure (SEOP) training required for each machine or source used

Training Completion Complete this PowerPoint presentation Receive SEOP training from machine or source supervisor For initial training, meet with Radiation Safety Officer for training review (rjgreve@nps.edu). An interview is not required for refresher training. NSAM Locksmith will provide access to secured areas Annual training must be completed each year following initial training

NRW Radiation Sources and Hazards Electron Microscopes Electron Microscopes rarely present a radiation hazard, although regulations require that electron microscopes be registered and labeled as radiation-producing equipment, and radiation surveys must be performed. Because radiation leakage may develop when shielding in the column is improperly installed, radiation surveys must be performed for any newly installed or relocated microscope, when the microscope has been modified for special experiments, and following any service work in which the column has been opened.

NRW Radiation Sources and Hazards X-Ray Diffractometer The NPS enclosed beam XRD uses a fail-safe sample closure chamber and beam shutter interlocks that exclude any part of the body from being exposed to radiation during normal operation. The inherent shielding of the chamber walls is sufficient to reduce radiation levels to levels that are indistinguishable from naturally occurring background radiation.

NRW Radiation Sources and Hazards Sabre 4000 The Sabre 4000 contains a sealed Nickel-63 source. The Beta emitting foil source is fully contained within the unit and radiation levels are indistinguishable from background radiation. Provided the physical integrity of the unit is maintained there is minimal radiation risk.

Biologic Effects of Radiation We tend to think of biological effects of radiation in terms of their effect on living cells. For low levels of radiation exposure, the biological effects are so small they may not be detected. The body has repair mechanisms against damage induced by radiation as well as by chemical carcinogens. Consequently, biological effects of radiation on living cells may result in three outcomes: (1) injured or damaged cells repair themselves, resulting in no residual damage; (2) cells die, much like millions of body cells do every day, being replaced through normal biological processes; or (3) cells incorrectly repair themselves resulting in a biophysical change (cancer). NRC website

Biologic Effects of Radiation Radiation can cause cell damage to Cell structure Chromosomes Damage may result in: Cell death Abnormal cell reproduction Cell repair Effects minimal if repaired faster than additional damage is done Rapidly dividing tissue is more susceptible to radiation exposure: Embryo/fetus

Radiation Risk In any group of 10,000 workers, about 2000 (20%) will normally die from cancer. If each of the 10,000 received over his or her career an additional 1 rem, then an estimated 4 additional cancer deaths (0.04%) might occur. Therefore, the average worker’s lifetime risk of cancer has been increased nominally from 20 % to 20.04%. Note-radiation surveys and posted dosimetry have not indicated any radiation levels from SEM/TEM/XRD operation above naturally occurring background radiation.

SEM/TEM/XRD Area Control Analytical Measurement Instruments (SEM/TEM/XRD) are located in controlled areas. Only Authorized Users are granted unescorted access. Access to these restricted areas are controlled by locking or guarding at all times. Prior to entering check the Authorized Users list posted on door to ensure your training is current.

SEM/TEM/XRD door posting

Do NOT Enter! Radiation Area-Do NOT Enter High Radiation Area-Do NOT Enter

Minimizing the possibility of radiation exposure As previously discussed, radiation exposure from SEM/TEM/XRD and Sabre 4000 operation not measurable above naturally occurring background when Standard and Emergency Operating Procedures are followed. However, it is still the NPS policy to maintain radiation exposure As Low As Reasonably Achievable (ALARA)using: Time Distance Shielding

Concepts of ALARA Time The less time you spend with a source the less exposure you will have from that source

Concepts of ALARA Distance The greater distance you have from a source the lower the exposure from that source. Radiation dose decreases by 1/Distance squared.

Concepts of ALARA Shielding The more shielding you have between you and the source the less exposure you will have from that source

Radiation is measured by: Personnel Dosimetry Personnel dosimeters (small radiation monitoring devices) are not required for SEM/TEM/XRD and Sabre 4000 operators. Radiation is measured by: Periodic and situational radiation surveys Work area dosimeters (e.g. XRD operators computer)

Radiation Surveys Radiation surveys must be performed prior to normal operation as follows: Prior to placing a new unit in service and semi-annually thereafter Immediately after maintenance or repair After shock, earthquake, etc., or suspected deficiency During beam realignment for open beam systems Following equipment modification

If you have any questions contact the instrument PI or the RSO: Ryan Greve, RSO (831) 656-2181 office (831) 915-1702 cell