CRPA(R) Prep, February 2019 / Préparation à la désignation (A)ACRP, février 2019
In this section of the Bulletin, we introduce a question or two similar to the questions on the CRPA(R) exam. In the next issue, we will provide the solution. The intention is to give people an idea of the types of questions that we use on the CRPA(R) exam and perhaps convince more members to challenge the exam.
If you already have your CRPA(R) designation, we invite you to submit questions to earn points for your registration maintenance!
Question from the last issue:
So, let’s take a look at the solution to the question from the last issue.
What is the transport index (TI) for a small package (less than 1 m2 cross-sectional area) being shipped as a “Category III – yellow” with the following dose rates?
Surface = 510 µSv/h
1 metre from surface = 43 µSv/h
10 metres from surface = 0.5 µSv/h
For anyone who sends any Class 7 shipments as part of their regular duties, or has had Class 7 TDG training, this question would be a freebie on a CRPA(R) exam! However, if you don’t routinely ship nuclear substances or haven’t heard the term “transport index” before, this question is a little more difficult.
If you plan to write the CRPA(R) exam and you don’t routinely ship nuclear substances, you are going to have to study the Transportation of Dangerous Goods (TDG) Regulations and the Packaging and Transport of Nuclear Substances Regulations (PTNSRs). The PTNSRs are provided at the exam, but the TDG Regulations and the International Atomic Energy Agency (IAEA) Transport Regulations (SSR-6) are not provided. The PTNSRs heavily reference the other two regulations (among others).
The following excerpt is from the Definitions section of the PTNSRs:
transport index has the same meaning as in the IAEA Regulations.
Seeing as you will not have the IAEA Regulations with you in the exam, you need to study them in advance. Before I wrote my CRPA(R) exam, I took a TDG Class 7 refresher course. I killed two birds with one stone—I did a little studying and got some work-appropriate training at the same time!
When you do get around to studying, you will discover that, according to the IAEA regulations (pages 62–63), the TI for a small package is determined by the following procedure:
523 (a) Determine the maximum radiation level in units of millisieverts per hour (mSv/h) at a distance of 1 m from the external surfaces of the package, overpack, freight container or unpackaged LSA-I and SCO-I. The value determined shall be multiplied by 100 and the resulting number is the TI.
. . .
(c) The value obtained . . . shall be rounded up to the first decimal place (for example, 1.13 becomes 1.2), except that a value of 0.05 or less may be considered as zero.
So, for this question, we were given three dose rates. We really only need the dose rate at 1 m of 43 µSv/h. (The other two dose rates have no bearing on the TI.) Then, the first step is to convert to mSv/h.
1000 µSv/h = 1 mSv/h.
Therefore: 43 µSv/h = 0.043 mSv/h.
Next, in accordance with the IAEA regulations, we multiply this number by 100. There is no unit for TI, but it is numerically identical to the dose rate at 1 m in mrem/h.
0.043 mSv/h × 100 = 4.3
The TI is 4.3 and the answer to our question is B.
The amount of light emitted by a scintillation phosphor is proportional to what feature of photon energy?