ML23163A118

Examination Report Letter No. 50-297/OL-23-01, North Carolina State University

ML23163A118
Person / Time
Site:	North Carolina State University
Issue date:	07/13/2023
From:	Travis Tate NRC/NRR/DANU/UNPO
To:	Hawari A North Carolina State University
References
50-297/23-01 50-297/OL-23
Download: ML23163A118 (3)

Text

June 13, 2023 Dr. Ayman I. Hawari, Director Nuclear Reactor Program Department of Nuclear Engineering North Carolina State University Campus Box 7909 2500 Stinson Drive Raleigh, NC 27695-7909

SUBJECT:

EXAMINATION REPORT NO. 50-297/OL-23-01, NORTH CAROLINA STATE UNIVERSITY

Dear Dr. Hawari:

During the week of May 8, 2023, the U.S. Nuclear Regulatory Commission (NRC) administered an operator licensing examination at your North Carolina State University research reactor. The examinations were conducted according to NUREG-1478, "Operator Licensing Examiner Standards for Research and Test Reactors," Revision 2. Examination questions and preliminary findings were discussed with those members of your staff identified in the enclosed report at the conclusion of the examination.

In accordance with Title 10 of the Code of Federal Regulations, Section 2.390, a copy of this letter and the enclosures will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of NRC's Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC website at http://www.nrc.gov/reading-rm/adams.html. The NRC is forwarding the individual grades to you in a separate letter which will not be released publicly. Should you have any questions concerning this examination, please contact Amy Beasten at (301) 415-8341 or via email at Amy.Beasten@nrc.gov.

Sincerely, Signed by Tate, Travis on 06/13/23 Travis L. Tate, Chief Non-Power Production and Utilization Facility Oversight Branch Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Docket No. 50-297

Enclosures:

1. Examination Report No. 50-297/OL-23-01

2. Written examination cc: w/o enclosures to GovDelivery Subscribers

ML23163A118 NRR-079 OFFICE NRR/DANU/UNPO/CE NRR/DANU/UNPO/OLA NRR/DANU/UNPO/BC NAME ABeasten NJones TTate DATE 6/13/2023 6/13/2023 6/13/2023 U. S. NUCLEAR REGULATORY COMMISSION OPERATOR LICENSING INITIAL EXAMINATION REPORT REPORT NO.: 50-297/OL-23-01 FACILITY DOCKET NO.: 50-297 FACILITY LICENSE NO.: R-120 FACILITY: North Carolina State University EXAMINATION DATES: May 08-10, 2023 SUBMITTED BY: _Amy E. Beasten 05/17/2023 Amy E. Beasten, Chief Examiner Date

SUMMARY

During the week of May 8, the NRC administered operator licensing examinations to four Reactor Operator (RO) candidates. All candidates passed all applicable portions of the examination.

REPORT DETAILS

1. Examiner: Amy Beasten, Chief Examiner, NRC

2. Results:

RO PASS/FAIL SRO PASS/FAIL TOTAL PASS/FAIL Written 4/0 0/0 4/0 Operating Tests 4/0 0/0 4/0 Overall 4/0 0/0 4/0

3. Exit Meeting:

Amy Beasten, Reactor Engineer, NRC Anna Deak, Reactor Health Physicist Assistant, North Carolina State University Gerald Wicks, Reactor Health Physicist, North Carolina State University Prior to administration of the written examination, based on facility comments, adjustments were accepted. Comments provided corrections and additional clarity to questions/answers and identified where changes were appropriate based on current facility conditions. Upon completion of all operator licensing examinations, the NRC examiner met with facility staff representatives to discuss the results. At the conclusion of the meeting, the NRC examiner thanked the facility for their support in the administration of the examination.

Enclosure 1

North Carolina State University PULSTAR Reactor Operator Licensing Examination Week of May 8, 2023 Enclosure 2

U. S. NUCLEAR REGULATORY COMMISSION NON-POWER REACTOR LICENSE EXAMINATION FACILITY: North Carolina State University Reactor REACTOR TYPE: PULSTAR DATE ADMINISTERED: May 08, 2023 CANDIDATE: _______________________

INSTRUCTIONS TO CANDIDATE:

Answers are to be written on the Answer sheet provided. Attach all Answer sheets to the examination. Point values are indicated in parentheses for each question. A 70% in each category is required to pass the examination. Examinations will be picked up three (3) hours after the examination starts.

% OF CATEGORY % OF CANDIDATE'S CATEGORY VALUE TOTAL SCORE VALUE CATEGORY 20.00 33.3 A. REACTOR THEORY, THERMODYNAMICS AND FACILITY OPERATING CHARACTERISTICS 20.00 33.3 B. NORMAL AND EMERGENCY OPERATING PROCEDURES AND RADIOLOGICAL CONTROLS 20.00 33.3 C. FACILITY AND RADIATION MONITORING SYSTEMS 60.00  % TOTALS FINAL GRADE All work done on this examination is my own. I have neither given nor received aid.

Candidate's Signature 2

NRC RULES AND GUIDELINES FOR LICENSE EXAMINATIONS During the administration of this examination the following rules apply:

1. Cheating on the examination means an automatic denial of your application and could result in more severe penalties.

2. After the examination has been completed, you must sign the statement on the cover sheet indicating that the work is your own and you have neither received nor given assistance in completing the examination. This must be done after you complete the examination.

3. Restroom trips are to be limited and only one candidate at a time may leave. You must avoid all contacts with anyone outside the examination room to avoid even the appearance or possibility of cheating.

4. Use black ink or dark pencil only to facilitate legible reproductions.

5. Print your name in the blank provided in the upper right-hand corner of the examination cover sheet and each Answer sheet.

6. Mark your Answers on the Answer sheet provided. USE ONLY THE PAPER PROVIDED AND DO NOT WRITE ON THE BACK SIDE OF THE PAGE.

7. The point value for each question is indicated in [brackets] after the question.

8. If the intent of a question is unclear, ask questions of the examiner only.

9. When turning in your examination, assemble the completed examination with examination questions, examination aids and Answer sheets. In addition turn in all scrap paper.

10. Ensure all information you wish to have evaluated as part of your Answer is on your Answer sheet. Scrap paper will be disposed of immediately following the examination.

11. To pass the examination you must achieve a grade of 70 percent or greater in each category and an overall grade of 70 percent or greater.

12. There is a time limit of three (3) hours for completion of the examination.

3

Category A: Reactor Theory, Thermodynamics, & Facility Operating Characteristics ANSWER SHEET Multiple Choice (Circle or X your choice)

If you change your answer, write your selection in the blank.

A01 a b c d ___

A02 a b c d ___

A03 a b c d ___

A04 a b c d ___

A05 a b c d ___

A06 a b c d ___

A07 a b c d ___

A08 a b c d ___

A09 a ________ b ________ c ________ d ________ (0.50 each)

A10 a b c d ___

A11 a b c d ___

A12 a b c d ___

A13 a b c d ___

A14 a b c d ___

A15 a b c d ___

A16 a b c d ___

A17 a ________ b ________ c ________ d ________ (0.25 each)

A18 a b c d ___

A19 a b c d ___

(***** END OF CATEGORY A *****)

4

Category B: Normal/Emergency Operating Procedures and Radiological Controls ANSWER SHEET Multiple Choice (Circle or X your choice)

If you change your answer, write your selection in the blank.

B01 a b c d ___

B02 a b c d ___

B03 a b c d ___

B04 a b c d ___

B05 a b c d ___

B06 a b c d ___

B07 a b c d ___

B08 a b c d ___

B09 a b c d ___

B10 a ________ b ________ c ________ d ________ (0.25 each)

B11 a b c d ___

B12 a b c d ___

B13 a b c d ___

B14 a ________ b ________ c ________ d ________ (0.25 each)

B15 a b c d ___

B16 a b c d ___

B17 a b c d ___

B18 a b c d ___

B19 a b c d ___

B20 a b c d ___

(***** END OF CATEGORY B *****)

5

Category C: Facility and Radiation Monitoring Systems ANSWER SHEET Multiple Choice (Circle or X your choice)

If you change your answer, write your selection in the blank.

C01 a b c d ___

C02 a b c d ___

C03 a b c d ___

C04 a b c d ___

C05 a ________ b ________ c ________ d ________ (0.25 each)

C06 a ________ b ________ c ________ d ________ (0.25 each)

C07 a b c d ___

C08 a b c d ___

C09 a b c d ___

C10 a b c d ___

C11 a b c d ___

C12 a b c d ___

C13 a b c d ___

C14 a b c d ___

C15 a b c d ___

C16 a b c d ___

C17 a b c d ___

C18 a b c d ___

C19 a b c d ___

C20 a b c d ___

(***** END OF CATEGORY C *****)

(********** END OF EXAMINATION **********)

6

EQUATION SHEET

2 eff 0.1sec 1 Q m c P T m H UAT Pmax 2

t P P0 e S S SCR

• 110 4 sec 1 K eff SUR 26 .06 eff CR1 1 CR2 2 CR1 1 K eff1 CR2 1 K eff 2 1 M 1

2 CR P P0 10 SUR (t )

P P0 1 K eff CR1 1 K eff

• 1 K eff1 SDM M K eff 1 K eff 2

=

+ 0.693 K eff 2 K eff1 T1 2

K eff1 K eff 2 K eff 1 K eff DR DR0 e t 2 2 DR1 d1 DR2 d 2 6 Ci E n DR 2 2 1 2 R2 Peak2 Peak1 1 Curie = 3.7 x 1010 dis/sec 1 kg = 2.21 lb 1 Horsepower = 2.54 x 103 BTU/hr 1 Mw = 3.41 x 106 BTU/hr 1 BTU = 778 ft-lb °F = 9/5 °C + 32 1 gal (H2O) 8 lb °C = 5/9 (°F - 32) cP = 1.0 BTU/hr/lb/°F cp = 1 cal/sec/gm/°C 7

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.01 [1.0 point]

The average energy release per fission with a thermal neutron in U-235 is _____ with the majority of energy being released from __________.

a. 200 MeV; kinetic energy of fission products

b. 200 MeV; energy of fission neutrons

c. 187 MeV; kinetic energy of fission products

d. 187 MeV; energy of fission neutrons QUESTION A.02 [1.0 point]

Which ONE of the following is the principal source of heat in the reactor after a shutdown from extended operation at full power?

a. Continued production of delayed neutrons.

b. Decay of fission fragments,

c. Xe-135 peaking due to burnout.

d. Spontaneous fission of Uranium-238.

QUESTION A.03 [1.0 point]

A subcritical reactor has a keff of 0.833. How much reactivity is added to change the keff to 0.975?

a. 0.146

b. 0.175

c. 0.461

d. 0.449 QUESTION A.04 [1.0 point]

Which ONE of the following isotopes has the largest microscopic absorption cross-section for thermal neutrons?

a. Uranium-235

b. Samarium-149

c. Boron-10

d. Xenon-135 8

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.05 [1.0 point]

How long will it take reactor power to increase from 25W to 500kW, if reactor period is 32 seconds?

a. 119 seconds

b. 157 seconds

c. 291 seconds

d. 317 seconds QUESTION A.06 [1.0 point]

Which ONE of the following describes the prompt neutron generation time?

a. The total time from the birth of a thermal neutron to the emission of the delayed neutron in the next generation.

b. The total time from the birth of the fast neutron to the emission of the delayed neutron in the next generation.

c. The sum of the amount of time it takes a fast neutron to thermalize, the amount of time the neutron exists as a thermal neutron before it is absorbed, and the amount of time between a fissionable nuclide absorbing a neutron and delayed neutrons being released.

d. The total time it takes a delayed neutron to be thermalized.

QUESTION A.07 [1.0 point]

Which ONE of the following best explains the importance of source neutrons?

a. Source neutrons ensure that there is a sufficient neutron population to provide visible indication of neutron level during start-up and shutdown.

b. Source neutrons ensure there is a sufficient neutron population to overcome the effects of fission product poisoning following a shutdown.

c. Source neutrons are essential to achieve and maintain criticality of the reactor.

d. Source neutrons are used to lengthen the neutron generation time to ensure the reactor does not go prompt critical.

9

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.08 [1.0 point]

Following a reactor scram from 800 kW, the reactor period has stabilized and power level is decreasing at a constant rate. What is the reactor power ten minutes following the scram?

a. 158 W

b. 442 W

c. 723 W

d. 1.24 kW QUESTION A.09 [2.0 points, 0.50 points each]

Match the terms in Column A with the result in Column B to complete the following statements.

Answers in Column B may be used once, more than once, or not at all:

As moderator temperature increases, [Column A] [Column B].

Column A Column B

a. Fast Fission Factor Increases

b. Thermal Utilization Factor Decreases

c. Resonance Escape Probability Stays the same

d. Reproduction factor QUESTION A.10 Which ONE of the following factors in the six-factor formula is affected by the enrichment of U-235 in the fuel?

a. Thermal Non-Leakage Probability

b. Fast Fission Factor

c. Fast Non-Leakage Probability

d. Resonance Escape Probability 10

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.11 [1.0 point]

In the figure below, which ONE of the following best describes Region I?

a. Neutron absorption cross-section steadily decreases as neutron energy increases in the fast neutron region.

b. Neutron absorption cross-section is inversely proportional to the neutron velocity (1/v).

c. Neutron absorption cross-section peaks in the thermal neutron energy region as a result of resonance absorption

d. Neutron absorption cross-section is directly proportional to the neutron energy.

QUESTION A.12 [1.0 point]

Given a reactor period of 25 seconds, how long will it take for reactor power to triple?

a. 15 seconds

b. 21 seconds

c. 28 seconds

d. 36 seconds 11

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.13 [1.0 point]

Which ONE of the following best describes the importance of a negative temperature coefficient of reactivity?

a. An increase in reactor power causes an increase in fuel temperature which results in a negative reactivity addition, causing the power increase to slow or stop.

b. An increase in reactor power causes an increase in fuel temperature which results in a positive reactivity addition, causing the power increase to slow or stop.

c. An increase in reactor power causes an increase in fuel burnup which results in a negative reactivity addition, causing the power increase to slow or stop.

d. An increase in reactor power causes an increase in fuel burnup which results in a positive reactivity addition, causing the power increase to slow or stop.

QUESTION A.14 [1.0 point]

Which ONE of the following statements regarding fission product poisoning is true?

a. During normal reactor operation, Sm-149 is removed from the core by both radioactive decay and neutron absorption.

b. Following a reactor shutdown, the concentration of Sm-149 reaches a peak because some fission is still occurring in the core.

c. During normal reactor operation, Xe-135 is removed from the core only by radioactive decay.

d. Following a reactor shutdown, the concentration of Xe-135 reaches a peak based on the decay of I-135 in the core.

QUESTION A.15 [1.0 point]

Which ONE of the following describes a fertile material?

a. A fertile material is a material for which fission caused by fast or thermal neutron absorption is possible provided the kinetic energy added to the binding energy is greater than the critical energy required for fission.

b. A fertile material is a material for which fission is possible with thermal neutrons alone provided the binding energy is greater than the critical energy required for fission.

c. A fertile material is a material that can undergo transmutation to become a fissile material.

d. A fertile material is a material that can undergo conversion to become a fissionable material.

12

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.16 [1.0 point]

Which ONE of the following best describes alpha decay?

a. The emission of an alpha particle from an unstable nucleus. The daughter has an atomic number two more than the parent nuclide and a mass number four more than the parent nuclide.

b. The emission of an alpha particle from an unstable nucleus. The daughter has an atomic number two more than the parent nuclide and a mass number four less than the parent nuclide.

c. The emission of an alpha particle from an unstable nucleus. The daughter has an atomic number two less than the parent nuclide and a mass number four less than the parent nuclide.

d. The emission of an alpha particle from an unstable nucleus. The daughter has an atomic number two less than the parent nuclide and a mass number four more than the parent nuclide.

QUESTION A.17 [1.0 point, 0.25 points each]

Match the neutron interactions in Column A with the appropriate definition in Column B. Options in Column B may be used only once.

Column A Column B

a. Particle ejection 1. A neutron enters a nucleus to form a compound nucleus before decaying by gamma emission

b. Scattering 2. A nucleus absorbs a neutron and splits into two parts of similar size

c. Radiative capture 3. A nucleus is struck by a neutron and emits a single neutron

d. Fission 4. A neutron enters a nucleus to form a compound nucleus, which becomes excited and ejects a new particle with the incident neutron remaining in the nucleus 13

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.18 [1.0 point]

A fast neutron will lose the most energy in a collision with which ONE of the following atoms?

a. H1

b. H2

c. C12

d. U238 QUESTION A.19 [1.0 point]

Which ONE of the following is defined as the balance between production of neutrons and their absorption and leakage in the core?

a. Infinite Multiplication Factor.

b. Effective Multiplication Factor.

c. Utilization Factor.

d. Reproduction Factor.

(***** END OF CATEGORY A *****)

14

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.01 [1.0 point]

In accordance with the NCSU PULSTAR Emergency Plan, which ONE of the following defines the Emergency Planning Zone (EPZ)?

a. The border that includes the reactor bay, control room, mechanical equipment room, ventilation equipment room, and primary piping vault.

b. The border that outlines the reactor building.

c. The area surrounding the Burlington Engineering Laboratories (BEL) between Lampe Drive, Broughton Drive, Stinson Drive, and the north face of BEL.

d. The area contained within 250 feet of the reactor building QUESTION B.02 [1.0 point]

Which ONE of the following accurately completes the following Technical Specification statement?

The sum of the absolute values of reactivity of all experiments in the reactor and experimental facilities shall not exceed ________.

a. 2890 pcm, including 300 pcm or 100 pcm/sec (whichever is more limiting) for moveable experiments, 1000 pcm for non-secured experiments, and 1590 pcm for secured experiments.

b. 2890 pcm, including 100 pcm or 300 pcm/sec (whichever is more limiting) for moveable experiments, 1000 pcm for non-secured experiments, and 1590 pcm for secured experiments.

c. 2890 pcm, including 300 pcm or 100 pcm/sec (whichever is more limiting) for moveable experiments, 1590 pcm for non-secured experiments, and 1000 pcm for secured experiments.

d. 2890 pcm, including 1000 pcm for moveable experiments, 300 pcm or 100 pcm/sec (whichever is more limiting) for non-secured experiments, and 1590 pcm for secured experiments.

QUESTION B.03 [1.0 point]

In accordance with NRP-OP-301, Reactor Fuel Handling, which ONE of the following fulfills the personnel requirements for fuel handling within the reactor core?

a. A Reactor Operator supervising all activities related to fuel handling, a Senior Reactor Operator on the console during fuel movement, and a fuel handler.

b. Manager of Engineering and Operation supervising all activities related to fuel handling, a Senior Reactor Operator on the console during fuel movement, and a fuel handler.

c. A Senior Reactor Operator supervising all activities related to fuel handling, a licensed Operator on the console during fuel movement, and a fuel handler.

d. A Senior Reactor Operator supervising all activities related to fuel handling and serving as the fuel handler, and a Reactor Operator on the console during fuel movement.

15

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.04 [1.0 point]

Which ONE of the following radiation monitors might alarm in conjunction with a loss of pool water event?

a. Control Room Radiation Monitor

b. Stack Gas Radiation Monitor

c. West Wall Radiation Monitor

d. Over-the-Pool Radiation Monitor QUESTION B.05 [1.0 point]

All of the following are Technical Specification requirements for operation EXCEPT:

a. Reactor pool water temperature shall not exceed 117°F.

b. The drop time of each control rod is not greater than 1.5 seconds.

c. The reactor building must be maintained at a negative differential pressure of 0.2 H2O with normal ventilation system in operation.

d. The pool water resistivity shall be 500 k-cm.

QUESTION B.06 [1.0 point]

A 40-mm thick sheet of lead placed at a certain location in a beam of gamma rays reduces the gamma radiation level from 500 mR/hr to 125 mR/hr. Approximately how much ADDITIONAL lead would be needed to reduce the gamma radiation level to 50 mR/hr?

a. 12 mm

b. 26 mm

c. 38 mm

d. 54 mm QUESTION B.07 [1.0 point]

A sample reads 175 mrem/hr at a distance of 3 meters from the source. How far away from the source will the reading be 50 mrem/hr?

a. 1.5 m

b. 2.4 m

c. 3.8 m

d. 5.6 m 16

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.08 [1.0 point]

An experiment reading 90 mrem/hr was removed from the reactor. Five hours later, it reads 15 mrem/h. What is the half-life of the experiment?

a. 0.52 hr

b. 1.1 hr

c. 1.9 hr

d. 2.7 hr QUESTION B.09 [1.0 point]

You are currently a licensed operator at the NCSU PULSTAR reactor. Which ONE of the following is a NOT requirement of 10 CFR 55, Operators Licenses?

a. All licensed operators must pass an annual written requalification exam.

b. All licensed operators must successfully complete a continuous requalification program, not to exceed 24 months.

c. All licensed operators must have a medical examination by a physician every 2 years.

d. All licensed operators must actively perform the functions of an operator or senior operator for a minimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per quarter to maintain active status.

QUESTION B.10 [1.0 point, 0.25 points each]

Match the conditions or events in Column A to the appropriate level of classification in Column B. Options in Column B may be used once, more than once, or not at all.

Column A Column B

a. Pool level drop of greater than 14 inches Notification of Unusual Event over a 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period.

Alert

b. Air effluent concentrations at the site boundary 100 mrem per hour Deep Site Area Emergency Dose Equivalent for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

c. Security breach of the reactor confinement.

d. Indicated radiation dose rates in the control room of 10 mR/hr.

17

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.11 [1.0 point]

In accordance with NRP-OP-105, which ONE of the following is NOT an immediate action if the pool water temperature exceeds 114 °F?

a. Reduce power and attempt to restore cooling.

b. Determine if core cooling has been lost.

c. Bypass the thermal switch and continue operating.

d. Notify the Designated Senior Reactor Operator.

QUESTION B.12 [1.0 point]

In accordance with 10 CFR 20, which ONE of the following correctly defines the total effective dose equivalent (TEDE)?

a. The sum of the effective dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposures).

b. The sum of the products of the dose equivalent to the organ or tissue and the weighting factors applicable to each of the body organs or tissues that are irradiated.

c. The concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> under conditions of light work, results in an intake of one ALI.

d. The sum of the products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to these organs or tissues.

QUESTION B.13 [1.0 point]

In accordance with NRP-OP-105, which ONE of the following actions should NOT be taken in the event of a loss of commercial power?

a. Verify ventilation is in confinement mode.

b. Secure the reactor.

c. Verify auxiliary generator has started.

d. Turn on sampling pumps to filter GM Radiation monitor.

18

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.14 [1.0 point, 0.25 points each]

Match surveillance requirements in Column A with the surveillance interval listed in Column B.

Options in Column B may be used once, more than once, or not at all.

Column A Column B

a. Operability of confinement system on Monthly auxiliary power Semi-Annually

b. Shutdown margin verification Annually

c. Channel calibration of linear power channels

d. Control rod drop time verification QUESTION B.15 [1.0 point]

During a routine Health Physics survey of B104, a dose rate of 150 mrem/hr at a distance of 2 feet from the pneumatic transfer system receiver is detected. How should this area be posted?

a. High Radiation Area

b. Radiation Area

c. Contaminated Area

d. No posting is required QUESTION B.16 [1.0 point]

In accordance with NRP-OP-101, all of the following are steps to be taken prior to starting up the reactor in natural convection mode EXCEPT:

a. Determine estimated critical rod position (ECP) and record in the logbook.

b. Ensure the Safety Channel range is 1 MW.

c. Adjust compensating voltage until the Log N Channel log level meter reads 1.1 E-1to 1.3 E-1 watts.

d. Verify if fueled experiments are scheduled.

19

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.17 [1.0 point]

Which ONE of the following individuals may assume the role of Emergency Operations Manager, in accordance with the NCSU Emergency Plan?

a. Manager of Engineering and Operations

b. Chief of Reactor Operations

c. Senior Reactor Operator

d. NCSU Radiation Safety Officer QUESTION B.18 [1.0 point]

Which ONE of the following modifications would NOT require a 50.59 evaluation?

a. Changing the frequency of the visual inspection of the fuel assemblies from biennially to every five years.

b. Doubling the amount of sample material in a previously approved beam tube experiment.

c. Replacing the over-the-pool radiation monitor with a scintillation detector.

d. Changing the scram setpoint of the Linear Power Level channel to 1.5 MW.

QUESTION B.19 [1.0 point]

In accordance with OP-104, which ONE of the following actions should be taken during experiment loading if sample reactivity approaches 300 pcm?

a. Slowly withdraw the sample and notify the DSRO.

b. Scram the reactor and notify the DSRO.

c. Place the reactor in manual mode and manually adjust control rod positions to ensure reactor power is maintained constant.

d. Stop experiment loading until DSRO approval is obtained to continue loading.

20

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.20 [1.0 point]

In accordance with NCSU Technical Specifications, a Senior Reactor Operator is required to be present at the facility during all of the following conditions EXCEPT:

a. Initial startup and approach to power.

b. Recovery from an unplanned or unscheduled shutdown or significant power reduction.

c. Any time a trainee is on the console.

d. Fuel or control rod movement within the reactor core or pool.

(***** END OF CATEGORY B *****)

21

Category C: Facility and Radiation Monitoring Systems QUESTION C.01 [1.0 point]

Which ONE of the following best describes the flow of primary coolant in forced convection mode?

a. Primary water flows upward from the reactor pool through the reactor core and then into the core plenum, through the N-16 delay tanks and the heat exchanger, then into the bottom of the reactor pool.

b. Primary water flows upward from the reactor pool through the reactor core and then into the core plenum, through the N-16 delay tanks and the heat exchanger, then into the top of the reactor pool.

c. Primary water flows downward from the reactor pool through the reactor core and then into the core plenum, through the N-16 delay tanks and the heat exchanger, then into the bottom of the reactor pool.

d. Primary water flows downward from the reactor pool through the reactor core and then into the core plenum, through the N-16 delay tanks and the heat exchanger, then into the top of the reactor pool.

QUESTION C.02 [1.0 point]

Which ONE of the following statements best explains the primary importance of the reactor confinement?

a. Confinement provides a controlled release path for radioactive particulates and gases so they can be filtered and passed up the stack for atmospheric dispersion.

b. Confinement prevents radioactive particulates and gases from being released to the environment during all operating conditions.

c. Confinement provides physical security of the reactor.

d. Confinement provides consistent atmospheric conditions for safe reactor operation.

QUESTION C.03 [1.0 point]

Which ONE of the following describes the NCSU PULSTAR fuel?

a. UO2 pellets enriched to < 4% or 6% U-235 with zircaloy-2 cladding.

b. UO2 pellets enriched to < 4% or 6% U-238 with zircaloy-2 cladding.

c. UO2 pellets enriched to < 4% or 6% U-235 with aluminum cladding.

d. UO2 pellets enriched to < 4% or 6% U-238 with aluminum cladding.

22

Category C: Facility and Radiation Monitoring Systems QUESTION C.04 [1.0 point]

With the reactor in automatic mode, what would cause the automatic control to switch back to manual mode?

a. The reactor power deviates by 5% of the requested power.

b. The Regulating Rod is inserted to 13 inches.

c. The Shim rods are fully withdrawn.

d. The Gang Drive switch is in the neutral position.

QUESTION C.05 [1.0 point, 0.25 points each]

Using the figure below, match the nuclear instrumentation in Column A to the correct location in the core in Column B.

Column A Column B

a. Startup Channel I

b. Log N Power Channel II

c. Linear Power Channel III

d. Safety Channel IV 23

Category C: Facility and Radiation Monitoring Systems QUESTION C.06 [1.0 point, 0.25 points each]

Match the setpoint in Column A with the correct Technical Specification requirement in Column B. Options in Column B may be used once, more than once, or not at all.

Column A Column B

a. Reactor coolant inlet temperature 120°F Safety Limit

b. Neutron count 2 cps Limiting Safety System Setting

c. Coolant flow rate 450 gpm Limiting Condition for Operation

d. Reactor power 1.3 MWt QUESTION C.07 [1.0 point]

A gaseous effluent commonly produced from reactor operation is _______ which is _______:

a. Rn-222; a naturally occurring isotope.

b. I-135; produced as a byproduct of fission.

c. H3; produced from irradiation of water.

d. Ar-41; produced from irradiation of air.

QUESTION C.08 [1.0 point]

What is the purpose of the > 9x104 cps control rod inhibit on the source range channel?

a. This inhibit ensures there is sufficient subcritical multiplication taking plant and sufficient counts are being measured to accurately indicate fission rate in the core.

b. This inhibit ensures that the Log-N Operate button is pressed to bypass the control rod inhibit when instrument overlaps have been verified to permit continued power ascension.

c. This inhibit ensures that there is sufficient voltage to the source range channel power supply to operate the reactor.

d. This inhibit ensures that the reactor period reading is on scale prior to continuing power ascension.

24

Category C: Facility and Radiation Monitoring Systems QUESTION C.09 [1.0 point]

All of the following describe the purpose of the N-16 Channel EXCEPT:

a. The N-16 channel is used to indicate reactor power level as a function of N-16 gamma decay as coolant passes through the core.

b. The N-16 channel is used as an auxiliary indication of the power level when detectors have been repositioned due to core changes.

c. The N-16 channel is used as a reference to determine power level during the transition between 500 kW and 900 kW.

d. The N-16 channel may be used to detect fuel leaks and could provide the first indication of a fuel pin failure.

QUESTION C.10 [1.0 point]

All of the following are ways in which confinement can be initiated EXCEPT:

a. Loss of power to the Radiation Alarm Panel.

b. Manual confinement pushbutton in the control room.

c. High power scram signal

d. Stack gas or particulate monitor alarm QUESTION C.11 [1.0 point]

Which ONE of the following describes what happens when a scram signal is received?

a. The scram relays are de-energized, the input signal from the SCRAM Logic Unit is removed, and the SCRAM Logic Unit interrupts power to the control rod magnets and causes an automatic shutdown of the reactor.

b. The scram relays are de-energized, the input signal from the SCRAM Logic Unit is initiated, and the SCRAM Logic Unit interrupts power to the control rod magnets and causes an automatic shutdown of the reactor.

c. The scram relays are energized, the input signal from the SCRAM Logic Unit is removed, and the SCRAM Logic Unit interrupts power to the control rod magnets and causes an automatic shutdown of the reactor.

d. The scram relays are energized, the input signal from the SCRAM Logic Unit is initiated, and the SCRAM Logic Unit interrupts power to the control rod magnets and causes an automatic shutdown of the reactor.

25

Category C: Facility and Radiation Monitoring Systems QUESTION C.12 [1.0 point]

In the event of a loss of normal electrical power, the uninterrupted power supply (UPS) will continue to supply power to the:

a. Control room and Reactor Bay emergency lighting.

b. The Radiation Monitoring rack and Control Room Distribution Panel.

c. The confinement fans and Control Room Distribution Panel.

d. The Radiation Monitoring rack and control console instrumentation.

QUESTION C.13 [1.0 point]

How do the N-16 delay tanks function?

a. The N-16 tanks have an a series of flow restricting orifices within the tanks which slow the flow of water through the primary coolant system for approximately 2.5 minutes, allowing time for the N-16 to decay.

b. The N-16 tanks serve as holding tanks, which allows time for the N-16 to decay.

c. The N-16 tanks have an internal baffling which slow the flow of water through the primary coolant system for approximately 2.5 minutes, allowing time for the N-16 to decay.

d. The N-16 tanks have an internal diffusor mixer, which perturbs the primary coolant in the tanks for approximately 2.5 minutes, allowing time for the N-16 to decay.

QUESTION C.14 [1.0 point]

In order to prevent unnecessary initiation of the evacuation and confinement systems, the radiation area monitors may be bypassed during normal operation under all of the following conditions EXCEPT:

a. The Process Monitors may be bypassed for no greater than two minutes following the return of pneumatic sample capsule.

b. The Process Monitors may be bypassed for no greater than one minute immediately after starting the pneumatic blowers.

c. The Over-the-Pool monitor may be bypassed for no greater than two minutes during the return of pneumatic sample capsule.

d. The Over-the-Pool monitor may be bypassed for no greater than five minutes during the removal of experiments from the reactor pool.

26

Category C: Facility and Radiation Monitoring Systems QUESTION C.15 [1.0 point]

What is the purpose of the pool water temperature scram?

a. To protect the demineralizer resins from degradation.

b. To protect the heat exchanger

c. To ensure the Safety Limit is not exceeded.

d. To ensure the Limiting Safety System Setting is not exceeded.

QUESTION C.16 [1.0 point]

Which ONE of the following statements best describes the flow of air through the ventilation system when confinement mode is initiated?

a. All the air discharged from the reactor building passes through the exhaust plenum, the prefilter, a main filter, the main exhaust fan, and up the stack.

b. All the air discharged from the reactor building bypasses the main exhaust fan, passes through the confinement fan filter trains, through a HEPA filter and a charcoal absorber, and up the stack.

c. All the air discharged from the reactor building passes through the exhaust fan, the prefilter, a main filter, the exhaust plenum, and up the stack.

d. All the air discharged from the reactor building passes through the main exhaust fan, the confinement fan filter trains, through a HEPA filter and a charcoal absorber, and up the stack.

QUESTION C.17 [1.0 point]

Which ONE of the following options correctly describes how primary coolant temperature is measured?

a. A thermocouple detects changes in pool temperature by measuring the voltage difference between two wires of dissimilar metals.

b. A resistance temperature detector detects changes in pool temperature by measuring changes in resistance to the flow of electricity resulting from changes in temperature of the resistive metal element.

c. A thermistor detects changes in pool temperature by using a thermally sensitive resistor that exhibits a continuous, small, incremental change in resistance correlated to variations in temperature.

d. A semiconductor-based temperature sensor detects changes in pool temperature by utilizing two identical diodes with temperature-sensitive voltage vs current characteristics that are used to monitor changes in temperature.

27

Category C: Facility and Radiation Monitoring Systems QUESTION C.18 [1.0 point]

The figure below depicts which ONE of the following nuclear instrumentation detectors?

a. Source Range Channel

b. Safety Channel

c. Log & Linear Channel

d. Linear Power Channel QUESTION C.19 [1.0 point]

Which ONE of the following is the Technical Specification definition of CHANNEL CHECK?

a. A Channel Check is a qualitative verification of acceptable performance by observation of channel behavior, or by comparison of the channel with other independent channels or systems measuring the same parameter.

b. A Channel Check is an adjustment of the channel such that its output corresponds with acceptable accuracy to known values of the parameter which the channel measures.

c. A Channel Check is the introduction of a signal into the channel for verification that it is operable.

d. A Channel Check is the measured value of a parameter as it appears on the output for a channel.

28

Category C: Facility and Radiation Monitoring Systems QUESTION C.20 [1.0 point]

In accordance with the NCSU Technical Specifications, which ONE of the following statements regarding pool water quality is NOT true?

a. The resistivity of the pool water shall be 500 k-cm.

b. The pH shall be within the range of 5.5 to 7.5.

c. Primary coolant pH shall be analyzed bi-weekly.

d. Pool water conductivity shall be measured monthly if the reactor is not operated.

(***** END OF CATEGORY C *****)

(********** END OF EXAMINATION **********)

29

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics A.01 Answer: a.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 61 A.02 Answer: b.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 61 A.03 Answer: b.

Reference:

Burn, Section 3.3.4, p 3-20-21

= (keff2-keff1)/(keff1*keff2)

= (0.975-0.833)/(0.975*0.833)

= 0.175 k/k A.04 Answer: d.

Reference:

Burn, Introduction to Nuclear Reactor Operations, Section 8.1 A.05 Answer: d.

Reference:

P(t) = P(0)et/T 500kW = 25W*et/32 500kW / 0.025kW = et/32 ln(20000) = ln(et/32) 9.903 = t/32 t = 317 s A.06 Answer: c.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 2, page 32 A.07 Answer: a.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 2, page 1 A.08 Answer: b.

Reference:

P = P0 e-t/T P = 800 kW

• e(600s/-80s)

P = 800 kW

• e(-7.5)

P = 0.442 kW = 442 W A.09 Answer: a. Stays the same; b. Increases; c. Decreases; d. Stays the same

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 3-16 A.10 Answer: d.

Reference:

DOE Fundamentals Handbook, Volume 2, Module 3, page 16 30

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics A.11 Answer: b.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 2, page 9-17 A.12 Answer: c.

Reference:

P = P0et/25 3 = 1et/25 ln(3) = ln(et/25) 1.0986 = t/25 T = 27.5 seconds A.13 Answer: a.

Reference:

DOE Fundamentals Handbook, Volume 2, Module 3, page 28 A.14 Answer: d.

Reference:

DOE Fundamentals Handbook, Volume 2, Module 3, page 30-47 A.15 Answer: c.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 50-55 A.16 Answer: c.

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 29 A.17 Answer: a. 4; b. 3; c. 1; d. 2

Reference:

DOE Fundamentals Handbook, Volume 1, Module 1, page 43-46 A.18 Answer: a.

Reference:

NRC standard question A.19 Answer: b.

Reference:

DOE Fundamentals Handbook, Volume 2, Module 3, page 15

(***** END OF CATEGORY A *****)

31

Category B: Normal/Emergency Operating Procedures and Radiological Controls B.01 Answer: b.

Reference:

NCSU PULSTAR Emergency Plan, page 7 B.02 Answer: a.

Reference:

NCSU PULSTAR Technical Specifications 3.2 B.03 Answer: c.

Reference:

NRP-OP-301, Reactor Fuel Handling B.04 Answer: d.

Reference:

NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions B.05 Answer: b.

Reference:

NCSU PULSTAR Technical Specifications 3.2, 3.3, 3.6, 3.9 B.06 Answer: b.

Reference:

DR = DRe-x; Find 125 = 500e-40 0.25 = e-40 ln(0.25) = ln(e-40)

-1.386 = -40

= 0.03466 Find X:

50 = 125e-0.03466X ln(0.4) = ln(e-0.03466X)

X = 26 mm B.07 Answer: d.

Reference:

DR1*(D1)2 = DR2*(D2)2 ;

175 mrem*(3 m)2 = 50 mrem(d)2 1575 mrem-m2 = 50 mrem(d)2 31.5 m2 = d2 d = 5.6 m B.08 Answer: c.

Reference:

DR=DR0e(-t) T1/2=0.693/

DR = DR0 e-.693/T1/2 15 = 90 e-(.693)(5)/T1/2 0.1667 = e-(3.465)/T1/2 ln(0.1667) = ln(e-(3.465)/T1/2)

-1.792 = -3.465 / T1/2 T1/2 = -3.465 / -1.792; T1/2 = 1.93 hr 32

Category B: Normal/Emergency Operating Procedures and Radiological Controls B.09 Answer: a.

Reference:

10 CFR Part 55 B.10 Answer: a. Notification of Unusual Event; b. Site Area Emergency; c. Alert;

d. Alert

Reference:

NCSU Emergency Procedure 4, Attachment 1 B.11 Answer: c.

Reference:

NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions B.12 Answer: a.

Reference:

10 CFR 20.1003 B.13 Answer: d.

Reference:

NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions B.14 Answer: a. Monthly; b. Monthly; c. Semi-annually; d. Annually

Reference:

NCSU PULSTAR Technical Specifications 4.2, 4.3, 4.5 B.15 Answer: a.

Reference:

10 CFR 20 B.16 Answer: b.

Reference:

NRP-OP-101, Reactor Startup and Shutdown B.17 Answer: c.

Reference:

NCSU PULSTAR Emergency Plan, Section 3.2.3 B.18 Answer: b.

Reference:

10 CFR 50.59 B.19 Answer: a.

Reference:

NRP-OP-104, Reactor Experiments B.20 Answer: c.

Reference:

NCSU PULSTAR Technical Specifications 6.1.4

(***** END OF CATEGORY B *****)

33

C.01 Answer: c.

Reference:

NCSU PULSTAR SAR 5.2 C.02 Answer: a.

Reference:

NCSU PULSTAR SAR 3.5.6 C.03 Answer: a.

Reference:

NCSU PULSTAR SAR Section 4, Table 4-10 C.04 Answer: b.

Reference:

NCSU PULSTAR SAR 7.3.2 C.05 Answer: a. IV; b. I; c. II; d. III

Reference:

NCSU PULSTAR SAR 4.2 C.06 Answer: a. SL; b. LCO; c. LSSS or LCO; d. LSSS or LCO

Reference:

NCSU PULSTAR Technical Specifications 2.1, 2.2, 3.3 C.07 Answer: d.

Reference:

NCSU PULSTAR SAR 11.1.1.1 C.08 Answer: b.

Reference:

NCSU PULSTAR SAR 7.4.3.1 C.09 Answer: c.

Reference:

NCSU PULSTAR SAR 7.4.3.5 C.10 Answer: c.

Reference:

NCSU PULSTAR SAR 6.2.1 C.11 Answer: a.

Reference:

NCSU PULSTAR SAR 7.4.1 C.12 Answer: d.

Reference:

NCSU PULSTAR SAR 8.2 C.13 Answer: c.

Reference:

NCSU PULSTAR SAR 5.2 34

Category B: Normal/Emergency Operating Procedures and Radiological Controls C.14 Answer: a.

Reference:

NCSU PULSTAR SAR 6.2.1 C.15 Answer: c.

Reference:

NCSU PULSTAR Technical Specifications 3.3 C.16 Answer: b.

Reference:

NCSU PULSTAR SAR 9.1 C.17 Answer: b.

Reference:

NCSU PULSTAR SAR 5.2 C.18 Answer: d.

Reference:

NCSU PULSTAR SAR 7.4.1 C.19 Answer: a.

Reference:

NCSU PULSTAR Technical Specifications 1.2 C.20 Answer: d.

Reference:

NCSU PULSTAR Technical Specifications 3.9 and 4.6

(***** END OF CATEGORY C *****)

(********** END OF EXAMINATION **********)

35