Reactor trivia

Question 1

The exposure rate of the turbine floor of a boiling water reactor plant could be expected to be decreased to less than 1% at least _____ after shutdown?

Answer 1

Five minutes. The nuclide of concern is N-16 and has a half life of 7.1 seconds.

Question 2

Remediation of areas contaminated with uranium mill tailings, under UMTRA, includes unrestricted release criteria of:

Answer 2

less than 20 uCi/hr inside habitable structures and radon levels less than 0.02 working level, not to exceed 0.03 working level.

Question 3

A “restricted area” is an area where an individual, if he were continuously present in the area, could receive a radiation dose

Answer 3

in excess of 2 mR in any one hour or in excess of 100 mR in one year.

Question 4

In the siting of nuclear reactors, the exclusion radius refers to

Answer 4

the distance downwind from the reactor that a person may receive either a dose of 25 rem to the whole body or 300 rem to the thyroid if he stands there for two hours after the onset of the postulated accident.

Question 5

Most operating light water nuclear reactors limit the release of radioactive noble gases through the use of:

Answer 5

Delay lines or tanks. Nobel (inert) gases cannot be filtered, or absorbed, so control lies with decay

Question 6

To use elevated release dispersion modeling during a design-basis accident, the release stack must be:

Answer 6

at least 2.5 times the height of the nearest adjacent building

Question 7

Immediate USNRC notification for an acute exposure is required

Answer 7

at 25 rem

Question 8

24-hour USNRC notification is required

Answer 8

at 1 time the annual limit

Question 9

Purpose of the main steam line radiation monitors at a BWR

Answer 9

Detection of gross fuel failure

Question 10

Main cause of shutdown radiation fields at a nuclear power plant is

Answer 10

Co-60. Activation of Co-59

Question 11

If personnel with doses less than 100 mrem/year are excluded, the average annual exposure for nuclear reactor workers is typically:

Answer 11

400-800 mrem. This number is probably lower.

Question 12

In general, the most important source of occupational radiation exposure at nuclear power plants is

Answer 12

neutron activation product activity.

Question 13

In non-power reactors the radionuclide that is the principal environmental emission is:

Answer 13

Ar-41

Question 14

Regulatory guide that specifies the noble gas concentration ragen for monitoring several configurations for PWRs and BWRs

Answer 14

Regulatory Guide 1.97

Question 15

Sample lines for plant vents must be designed to minimize sample line losses. As a general rule, the sample line should be designed to

Answer 15

Maximize velocity and diameter, while minimizing distance

Question 16

40 CFR 190 requires that nuclear power plants maintain the dose to the maximally exposed member of the public to less than

Answer 16

0.25 mSv/yr. 25mrem.

Question 17

All individuals who are employed by a company must receive instruction in the health protection problems associated with excessive exposure to radiation if they are likely to receive:

Answer 17

1 mSv. or 100 millirem. The upper bound of allowable dose to the general public.

Question 18

If Kr-90 is released from the stack of a nuclear powerplant, what radionuclide would be detected from its decay chain?

Answer 18

Sr-90.

Question 19

What is the “Lapse Rate”

Answer 19

Temperature gradient of the atmosphere. Variable used in evaluating downwind discharges from stacks.

Question 20

An atmospheric inversion is one in which the lapse rate is:

Answer 20

Positive. If the lapse rate is positive, then the air temp increases with increasing height.

Question 21

using a GM probe on individuals exposed during criticality accidents, the rule of thumb is that for every 0.1 mR/hr, the exposure is ___ Rad

Answer 21

15