RP FUN1 part 4

Explain actions to take to determine the cause of an alarm on electronic dosimetry.

-When the SRD alarmed, where were you and what activities were you involved in? • What were the expected dose rates in the area? • Were you leaning against anything at the time of the alarm? • What activities were going on around you when your SRD alarmed? • What kinds of equipment were you using or were nearby? • Did you drop your dosimeter? • Were there any co-workers with you in the work area? • Did you compress your SRD against a hard surface)? - Determine if the alarm was due to a radiation or non-radiation event. - Working on the wrong RWP I Task - Obtain dose rate survey - Restrict RCA access based on plant procedures

The use of step-off pads (SOP) provides an effective method of contamination control by serving as:

1) A boundary of the contaminated area. 2) The access point to the contaminated area. 3) A double SOP is for Highly Contaminated Areas and Discrete Radioactive Particle Zones/Areas.

With RP Supervisor approval, items which have been surveyed and found to be radioactive can be temporarily released based on what 7 requirements:

1) Item is labeled as radioactive material in accordance with NISP-RP-04, Radiological Posting and Labeling. 2) No loose surface contamination 3) No potential for spills or leaks 4) Item is being transported to an area that satisfies NISP-RP-04, Radiological Posting and Labeling, 5) Individual transporting the material is logged in on the appropriate RWP and understands the requirements of transporting the material 6) The dose rate on the item is <2.0 mrem/hr at 30cm. 7) Conditionally released items are to be documented on a Radioactive Material Log or similar document.

Give two reasons why CRUD is undesirable in a reactor coolant system.

1. Deposits throughout the system will increase general radiation levels. 2. CRUD will also cause the fouling of the core heat transfer surfaces.

What actions may be require if someone looses or damages their dosimetry or suspects their dosimetry is not operating correctly.

1. If the individual's DLR(s) is lost, damaged, or requires processing, restrict the workers RCA access. 2. Obtain the SRD histogram 3. If required, the worker's DLR will be processed.

Boiling Water Reactor (BWR) Design Describe the basic operation of a BWR.

1. The core inside the reactor vessel creates heat. 2. A steam-water mixture is produced when very pure water (reactor coolant) moves upward through the core, absorbing heat. 3. The steam-water mixture leaves the top of the core and enters the two stages of moisture separation where water droplets are removed before the steam is allowed to enter the steam line. 4. The steam line directs the steam to the main turbine, causing it to turn the turbine generator, which produces electricity. 5. The unused steam is exhausted to the condenser, where it is condensed into water. The resulting water is pumped out of the condenser, reheated, and pumped back to the reactor vessel.

Describe the basic operation of a commercial Pressurized Water Reactor (PWR)..

1. The core inside the reactor vessel creates heat. 2. Pressurized water in the primary coolant loop carries the heat to the steam generator. 3. Inside the steam generator, heat from the primary coolant loop vaporizes the water in a secondary loop, producing steam. 4. The steam line directs the steam to the main turbine, causing it to turn the turbine generator, which produces electricity. 5. The unused steam is exhausted to the condenser, where it is condensed in to water. The resulting water is pumped out of the condenser back to the steam generator

The annual average radiation exposure to nuclear plant workers is less than ______________ mrem.

1000

On the average, approximately _________ MeV of energy is released per fission.

200

BWRs contain between _______ to ______ fuel assemblies. PWRs contain between ______ to ______ fuel assemblies.

370 to 800, 150 to 200

a 100 Ci Ir-192 source will generate a dose of about ______ rem/hr at one meter. The on contact dose rate on the shielded camera would be around _______ to________ mrem/hr.

50, 30, 40

Activated corrosion material such as cobalt, iron, chromium, manganese, zirconium, nitrogen, cesium, iodine, and xenon. are known as _______________________..

CRUD

While providing good wear-resistance, the _______________ in the Stellite alloy became a significant contributor to personnel exposure. When atoms of Cobalt-59 are subjected to a ________________ flux in the reactor core, they ______________ a neutron, and become activated, yielding Cobalt-60, a ____________-_______________ radioactive isotope.

Cobalt-59, neutron, absorb, long-lived

Loss of contamination control can be caused by Human errors that can occur when performing tasks either remotely or hands-on. State 5 examples of human errors that can cause the spread of radioactive contamination.

Errors such as: improper system valve lineup, overfilling of tanks, over pressurization of equipment/systems, improper use of equipment/tools, improper identification of systems/components to be opened (aka breached), and improper handling of radioactive materials.

______________ occurs when the nucleus of a uranium 235 atom (lesson common uranium 238) captures a _________________, becomes unstable, and splits into _________and __________ lighter nuclei. These nuclei are referred to as _____________________ products.

Fission, neutron, two, three, fission

Explain fission product leakage.

Fuel rods are sealed to contain fission products, however, minor defects do develop and some fission products leak from the fuel into the reactor coolant system.

Many facilities find it effective to use two different types of RWPs. Name and describe the two types of RWPs.

General RWPS are used for entry and repetitive work in areas with known and stable low-hazard radiological conditions. Job specific RWPs are used for more complex work and for entry into higher-hazard areas.

These type permits should be used to control may be used to control routine or repetitive activities, such as tours and inspections or minor work activities, in areas with well-characterized and stable radiological conditions.

General RWPs

This type RWP should not be approved for periods longer than 1 year.

General RWPs

State the methods that can be used when removing materials from a contaminated area:

Items may be placed in a bag, container or wrapped as they are removed from the contaminated area and taken directly to a location established for surveying and labeling/tagging the items/equipment. Items not contained, but under RP control while in a contaminated area; may be removed from contaminated area as long as it has been decontaminated and proven "Clean" smearable survey has obtained.

These type permits should be used to control non-routine operations or work in areas with changing radiological conditions.

Job-specific RWPs

________________ is a phenomenon has been observed where, hours or days after decontamination of an item has been performed, the contamination levels have increased.

Leaching

_____________________ becomes a concern when materials have been released from a radiologically controlled area as meeting specific removable contamination guidelines and later are found to be contaminated.

Leaching

Describe neutron activation of corrosion products.,

Metal components that make up the reactor coolant system corrode and the corrosion products accumulate in the core where they are exposed to a high neutron flux and become activated.

Activated corrosion products (CRUD) and fission products are often deposited in low flow areas (e.g. dead legs, valves, bends in pipes) of systems containing radioactive liquids. As the radioactivity in these ____________ _____________accumulates with time, the exposure rates increase resulting in ______ _________.

"crud traps", "hot spots"

Cross Contamination occurs after the initial contamination event and the contamination may be transported or spread to other areas of the facility. State 4 of the ways that contamination may be spread.

- Contaminated dust may become airborne and carried to uncontaminated areas by ventilation systems. - Improper decontamination techniques or work habits. - Transferred to personnel clothing and skin and transport to uncontaminated areas. - Releasing of contaminated equipment to uncontaminated areas.

A gate valve can be used for a wide variety of fluids and provides a tight seal when closed. The major disadvantages to the use of a gate valve are:

- It is not suitable for throttling applications. • It is prone to vibration in the partially open state. • It is more subject to seat and disk wear than a globe valve. • Repairs, such as lapping and grinding, are generally more difficult to accomplish.

State some basic methods to minimize radioactive waste.

- Minimize the materials used for radiological work. -Take only the tools and materials you need for the job into areas controlled for radiological purposes.. -Unpack equipment and tools in a clean area. -Use tools and equipment that are identified for radiological work, such as a hot tool room. -Use only the materials required to clean the area. -Sleeve, or otherwise protect with a covering such as plastic, clean materials brought into contaminated areas. -Separate radioactive waste from nonradioactive waste. -Do not place radioactive waste in nonradioactive waste containers. -Separate compactable material from non-compactable material. -Minimize the amount of mixed waste generated. -Use good housekeeping techniques.

Give 5 basic functions of valve.

- Stopping and starting fluid flow • Varying (throttling) the amount of fluid flow • Controlling the direction of fluid flow • Regulating downstream system or process pressure •Relieving component or piping overpressure

This type RWP should remain in effect only for the duration of the job.

The job-specific RWP should remain in effect only for the duration of the job.

This valve part which connects the actuator and disk, is responsible for positioning the disk.

The stem

_______ or _________ neutrons are usually released during the fission process.

Two, three

A fibrous material (such as flax) or another compound (such as Teflon) that forms a seal between the internal parts of a valve and the outside where the stem extends through the body.

Valve Packing

State the Clothing removal process when exiting a contamination area with aa Single Step-off Pad:

While in contaminated area: Remove protective clothing except inner booties and cotton glove liners. Discard clothing and trash into appropriate containers. When stepping onto Step-off Pad: 1) With back towards the SOP, remove one bootie and place foot on step-off pad. Repeat for other bootie. 2) Discard shoe covers in appropriate container.

How do workers acknowledge that they have read, understand, and will comply with the RWP prior to initial entry to the area and after any revisions to the RWP.

Workers should acknowledge by signature, or through electronic means where automated access systems are in place

The valve trim typically includes what parts?

a disk, seat, stem, and sleeves needed to guide the stem.

Radiation Work Permit Required Information The RWP should include the following information:

a. Description of work b. Work area radiological conditions c. Dosimetry requirements d. Pre-job briefing requirements, as applicable f. Protective clothing and respiratory protection requirements g. Radiological Control coverage requirements and stay time controls, as applicable h. Limiting radiological conditions that may void the RWP i. Special dose or contamination reduction considerations j. Special personnel frisking considerations

Step-off pads are provided at ______________ points to contaminated areas ____________ to the contaminated area boundary. Located in ____________ dose waiting areas.

access, adjacent, low

Contamination originates primarily from releases of ______________ or ______________ radioactivity to the surrounding area from systems or components. Contamination is likely to result from equipment ___________, human _____________ and maintenance operations

airborne, liquid, failures, error

The cover for the opening in the valve body is the ______________ which is also the second principal pressure boundary of a valve

bonnet.

When surveying valves always take a dose rate at the _________________ of the valve to ensure you have found the___________________ dose rate.

bottom, highest

In the passage of radiation through a medium, the ratio of the total value of a specified radiation quantity at any point to the contribution to that value from radiation reaching the point without having undergone a collision. This statement defines the term ________________ ___________________.

buildup factor

Step-off pads are considered radiologically ___________. In the areas of high contamination, an _______________________ step-off pad (double step-off pad) may be used. In that case, one step-off pad marks an area of _______________contamination and the other is considered clean.

clean, additional, lower

For a valve having a bonnet, the ___________ is the _______________ primary principal pressure boundary. The disk provides the capability for permitting and prohibiting __________ flow.

disk, third, fluid

Nuclear power reactors are fueled with uranium that is slightly __________________ in the isotope _______________ - ____________. This isotope is capable of sustaining a controlled nuclear ___________reaction that is necessary for production of electrical energy.

enriched, uranium 235, chain

Since the packing is made of a fibrous material, if a valve starts to leak through the packing this material can act like a __________ causing radioactive contamination to _________________ in this location. This can become a significant _____________________concern depending on the radioactivity in the water.

filter, concentrate, radiological

Since transuranics are heavy nuclei, a large number of these radionuclides are ______________________ and/or ________________ emitters

fissionable, alpha

Give 5 examples of the common types of valves:

globe valve, gate valve, ball valve, plug valve, butterfly valve, diaphragm valve, check valve, pinch valve, and safety valve.

Valve Bonnets can complicate the manufacture of valves, ___________ valve size, represent a significant cost portion of valve cost, and are a source for potential ______________.

increase, leakage

Performance of maintenance operations often produces contamination by opening systems and components containing airborne or liquid radioactivity. Examples of this would be;

maintenance on system components that require grinding, welding or cutting contaminated components.

Radionuclides may occur _________________, but can also be _________________ produced.

naturally, artificially

Radionuclides are present in the reactor coolant system as a result of what two processes?

neutron activation and fission product leakage.

A major hazard associated with loose contamination is that:

often, it may be readily spread. As a result, contamination may be found far from the area where it originated.

The disk of a gate valve is completely removed from the flow stream when the valve is fully _______________. This characteristic offers virtually no ________________________ to _____________ when the valve is open.

open, resistance, flow

Valves typically start leaking at two locations, name these locations.

packing and body to bonnet

The essential principle of globe valve operation is the ____________________ movement of the ____________ away from the seat. This causes the annular space between the disk and seat ring to ______________ close as the valve is closed. This characteristic gives the globe valve good _________________ ability, which permits its use in regulating flow.

perpendicular, disk, gradually, throttling

Plant systems that contain radioactive liquids, solids, or gases (air) can develop leaks to the surrounding area. These leaks are typically found at? ( Give 5 common locations for leaks to occur)

pipe flanges, sealing surfaces (such as pump seals, manways, handholes), through valve packing or other piping and equipment failures that can release radioactive materials into the surrounding areas.

A radionuclide is an atom with an unstable nucleus. Its nucleus is unstable because it has excess energy to give away, when this happens, the radionuclide undergoes _____________ ____________, and emits a radiation _________________or _______________ ray.

radioactive decay, particle, gamma

Minimization Waste One of the potential consequences of working with radioactive material is the generation of _____________________ __________________.

radioactive waste

Radiological hazards associated with valves vary depending on the amount of _________________ in the water being transfer through the system. However in general terms the _________________ of the valve will often contain the highest dose rates due to the small _________________ of the valve seat.

radioactivity, bottom, indentation

Identify the basic parts of a valve.

the body, bonnet, trim (internal elements), actuator, and packing.

Neutron capture can induce radioactivity through _______________________ of one chemical element into another. The transmutation process results in the __________________of nuclear particles (e.g., protons) and radiation from the __________________.

transmutation, emission, nucleus

The internal elements of a valve are collectively referred to as a valve's ___________________.

trim.

A ____________ is a mechanical device that controls the flow of fluid and pressure within a system or process.

valve

This valve component operates the stem and disk assembly

valve actuator

A Basic Scenario for Fuel Handling Incident: If one or more fuel bundles drop into the fuel pool or reactor cavity areas and breaks open, what would be the expected results?

• This releases the gaseous contents within the fuel rods into the refuel water. • Affected ARMs may or may not alarm because of the high ratio of beta emitters to gamma emitters in the released gasses. • Personnel may be subsequently exposed to noble gas and iodine vapor activity. This yields immersion dose from the noble gas and thyroid dose from the iodine

What is a transuranic?

Transuranic refers to any element with an atomic number greater than that of uranium.

Explain why reactor coolant cleanup systems are a source of radiation exposure..

A percentage of reactor coolant is continuously being taken from the reactor coolant system for removal or cleanup of radioactive material. Since these cleanup systems now contain reactor coolant water, which is radioactive, the cleanup systems collect this material and are a source of radiation exposure.

Define Radiological Work Permit (RWP):

A permit that identifies radiological conditions, establishes worker protection and monitoring requirements, and contains specific approvals for radiological work activities. The radiological work permit serves as an administrative process for planning and controlling radiological work and informing the worker of the radiological conditions.

________________________ is a non-destructive testing technique used to inspect welds, piping, and other components.

Radiography

Define radionuclide.

An atom with an unstable nucleus. Its nucleus is unstable because it has excess energy to give away, either to a newly-created radiation particle inside of the nucleus or to an electron orbiting the nucleus.

Give 4 examples of elements that are transuranics.

Any 4 of the following elements U239, Np239, Pu238, Pu240, Pu241, Am241, Cm242, Cm243, Cm244

A tacky Step-off Pad should be used at the exit of:

Discrete Radioactive Particle (DRP) Areas:

A physical reaction where a stable atom receives an additional neutron and becomes unstable (radioactive).

Neutron activation

Explain why valve internals removed from a radioactive system could present significant radiological hazards.

On radioactive systems, the internals have been in constant contact with contamination and a significant build up should be expected. Alpha contamination can also be presence if the station has experienced failed fuel and most units have at some point in their operating history.

State the process for removing material from a Contaminated Area:

Prior to any personnel removing items/equipment from a contaminated area; it is required that the workers first notify RP of their intent to remove the items/equipment. RP then coordinates with the workers to have RP job coverage provided for removal of equipment from a Contaminated Area.

Define radioactive Contamination.

Radioactive material in an unwanted location, e.g., personnel work areas, etc. Two types are possible:

Define Loose Contamination.

Radioactive surface contamination that is easily transferred to other personnel or equipment through normal contact.

Define Fixed Contamination.

Radioactive surface contamination that is not easily transferred to other personnel or equipment through normal contact.

_______________ is used in applications where a tough surface is required for components subject to movement with metal to metal contact.

Stellite

___________________ is the trademarked name for various alloys of chromium and cobalt that are formulated to be wear-resistant.

Stellite

This is the primary pressure boundary of a valve. It serves as the principal element of a valve assembly because it is the framework that holds everything together.

The body, sometimes called the shell,

Define Cross-Contamination:

The uncontrolled spreading of radioactive contamination on/into people, places or things.

Under some circumstances, absorption of a neutron by an atomic nucleus may result in the splitting of the nucleus into at least two smaller nuclei with an accompanying release of energy. What is this process called?

This process is called fission.

What is the purpose of valve packing?

This valve material is used to prevent leakage from the space between the valve stem and the bonnet.

How does the ALARA concept relate to minimizing radioactive waste?

This will reduce personnel exposure associated with the handling, packaging, storing, and disposing of radioactive waste. This will also reduce the resultant costs. It is very important for each radiological worker to minimize the amount of radioactive waste generated.

Processes such as: grinding, peeling of contaminated painted surfaces, scaling or drying of contaminated components or open systems can produce _________________ _____________________.

loose contamination

Radiological surveys should be routinely __________________ to evaluate the ________________ of RWP requirements. RWPs should be ____________ if radiological conditions change to the extent that protective requirements need modification.

reviewed, adequacy, updated

What are the two types of valve stems?

rising stems and non-rising stems.

Many valves require a partition across the valve body to support the ______________ opening, which is the throttling ______________.

seat, orifice

In the nuclear power industry, Stellite was originally used for valve _______________, pump ____________, roller bearings on control rods, and the leading edges of turbine ______________, among other applications.

seats, seals, blades

Step-off pads should not be located in areas where a safety hazard may result, such as in ______________ or _________________.

stairwells, elevators

A gate valve is a linear motion valve used to:

start or stop fluid flow; however, it does not regulate or throttle flow.

A globe valve is a linear motion valve used to:

stop, start, and regulate fluid flow.

The most common fission products are _________________ 90 and ___________137. Noble gases, for example ______________ 85 and ____________133 can also be produced from fission products.

strontium, cesium, krypton, xenon