Internal Monitoring Equipment

Question 1

Equipment used to perform internal monitoring

Four RADIACS used for internal Monitoring in conjunction with NNPP

Answer 1

PRM-5 with SPA-3 probe
(Single channel analyzer only used on CVN’s and being phased out)

AN/PDR-79 (IM-253/PD with SPA-3) use on CVN’s

Canberra FASTSCAN Whole Body Counter (WBC) Multi-channel Analyzer (MCA)

Canberra ASA-100 MCA- NaI(TI) crystal

all are scintillation detectors

Question 2

PRM-5 with SPA-3

Answer 2

Detect low level gamma radiation. Portable, battery operated. Pulse Rate meter.

Responds energy range- 1.0 - 1.5 MeV for 60Co

Question 3

AN/PDR-79 with SPA-3

Answer 3

used to detect low level gamma radiation. Portable battery operated. Pulse rate meter.

1.0 to 1.5 Mev for 60Co detection

Question 4

Canberra FASTCAN

Answer 4

Stand up counter with two vertically stacked sodium iodide detectors. each 5 x 3 x 16 analyzes 100keV to 2100keV.

used at Navy Nuclear Power School

Question 5

Canberra ASA-100 MCA

Answer 5

Detect low level gamma radiation. connected to 3 x 3 NaI crystal.

Question 6

Principle behind scintillation

Answer 6

Device that converts the kinetic energy of ionizing radiation into light quanta

reacts with crystal freeing an electron leaving behind a hole

electron and positive hole migrate to the activator sites in the crystal

positive hole ionizes the activator site allowing freed electron to drop into excited state

electron emits a visible light photon as it de-excites

Question 7

Minimum detectable activity (MDA) for the instruments used in internal monitoring

Answer 7

PRM-5 and SPA-3 probe and the AN/PDR-79- 10nCi- MDA 10nCi

Canaberra ASA-100 - MDA 5nCi

Canberra FASTsCAN MDA is 2nCi

Question 8

List when internal monitoring is performed

Per- P-5055

Answer 8

Adults likely to receive 10% of an ALI in one year

Minors likely to receive a CEDE in excess of 0.1 rem

Declared pregnant workers likely to receive 0.1 rem during their pregnancy

Anyone who potentially inhales, ingested, absorbed, injected measurable amount of radioactive material of a mishap

Deemed necessary by cognizant MO, RHO, or RH director

No more than 3 months before starting duties involving potential of internal intake

Periodically on individuals performing duties with potential of internal intake

Question 9

NNPP

Nuclear trained personnel authorized to receive occupational exposure receive internal monitoring

Answer 9

1. Prior to being initially authorized to receive occupational radiation exposure
2. At least within 180 days prior to separation from Naval Service or being transferred to a billet not directly associated with NNPP
3. Occurrences suspected radioactivity was taken into body
   a. wetted above the waist
   b. documented skin contamination
4. Periodically, in conjunction with medical exam
5. Conjunction with a radiation medical examination (shipyard)
6. When deemed necessary by RHO