Q239. Name four substances that are used for shielding against Gamma radiation at the Plutonium plant?

A.       1. Lead bricks                     : Service corridor blister.

           2. Concrete                         : Cell opening

           3. Water                              : Storage pond, FHA.

           4. Steel plates                      : Cell door.

Q240. Name two survey instruments commonly used at the Plutonium plant? What are their differences?

A.       1. Gun Monitor: It is an ionization chamber. It measures the integrated dose.

           2. GM Survey Meter: Used as a pulse instrument to detect individual particles.

Q241. Name two devices used at the Plutonium plant for measuring the radiation dose received by

           operation? How do they work.

A.      1. Film badge: Radiation has got a blackening effect on the film. By measuring this blackening, dose can be estimated.

           2. Dosimeter: It is an ionization chamber with a quartz-fibred electrometer.

Q242. Name the four routs through which radioactive material can enter the human body?

A.       1. Wound & cuts, 2. skin, 3. Injection by mouth, 4. Inhalation.

Q243. Name two methods for detecting the presence of radioactive material in the human body.

A.       1. Whole body counting, 2. Bio-assay: Urine and stool samples.

Q244. Write a short note on the ventilation of active areas at the Plutonium plant.

A.      The ventilation is from low active area to high active area. The high active area is always kept at negative pressure with respect to adjacent low active area. The air from active area goes through absolute filters and gets released through the stack.

Q245. What is a continuous Air Monitor? What is its use?

A.       Continuous Air Monitor: The air is sucked through an absolute filter (HV-70) continuously. The dust collected on the filter paper will be counted continuously. This can detect air borne contamination at any time without much delay.

Q246.  What is ‘Air Sampling’? How is it carried out? Why should air be sampled?

A.      Air sampling is a system by which dust in air can be filtered and counted for activity. A known volume of air is sucked through the paper and dust will be collected on the paper. By counting this paper directly we can estimate activity. This is useful for detecting air borne contamination.

Q247.  What are the different types of respirators used at the Plutonium Plant? What are the difference

            between them?

A.       1. Dust respirator: This is an absolute filter for dusts.

           2. Gas Mask: Useful for dusts as well as gases.

           3. Fresh Air line: This supplies air through a hose pipe. Can be used for much longer time than the other two.

Q248. Why is the plutonium plant stack so tall? What is the radioactive gas that is released through the stack

            during dissolution of the fuel.

A.       Since the plutonium plant is surrounded by high hills on one side, the stack has to be higher than these hills. During dissolution Krypton 85 is released.

Q249. What is the use of the delay tank at the plutonium plant?

A.       It is a storage tank of active water before disposal into sea.

Q250. What is the maximum permissible whole body dose for – 1. one year, 2. any 13 weeks?

A.       1. 3 Rem/year, 2. 1.5 Rem/13 weeks.

Q251. How long can you work in a radiation level of 3 R/hr, if your exposure should not exceed 200

           milliroentgers?

A.       Radiation level 3 R/hr, i.e. 3000 mR/hr

                            1 x 200

            200mr -------------  = 2/30^th hour.  i.e. 2/30 x 60 = 4 minutes.

                              3000

Q252. What procedures will you adopt for removing radioactive contamination from the skin? What

           precautions should be taken?

A.       1. Brush very lightly and for a long time with soap and water paying special attention to the nails.

           2. If this fails this fails titanium dioxide paste may be applied and subsequently washed off with soap and water.

          3. EDTA: Soap mixture can be tried next.

          4. As a last resort, hands may be immersed in acidified saturated potassium permanganate solution,    rinsed in water and the stain removed with a 5% solution of sodium bisulphite.

Q253. What is meant by 1. Rubber area, 2. Respiratory area?

A.       1. Rubber area: Whenever floor contamination is detected, that particular area will be treated as   Rubber area.

              2. Respiratory area: Whenever air borne contamination exceeds in certain limit (say one tolerance) that area will be treated as Respiratory area.

Q254. What precautions will you take to prevent spread of contaminati0on in the event of radioactive spill?

A.       1. Spill should be confined.

           2. Put cotton waste around it.

           3. Condon off that area.

           4. See any air borne activity is there.

           5. Arrange for decontamination.

Q255. What is Glove box? What is the difference between a Glove box and Fume hood?

A.       Glove box is a total containment facility for handling radioactive materials. Fume hood offers only partial contamination. Maximum 1 gram of Pu can be handled in a fume hood.