Text

Examination Report Letter No. 50-297 OL-24-01, North Carolina State University
	ML24052A120
Person / Time
Site:	North Carolina State University
Issue date:	06/04/2024
From:	Travis Tate; NRC/NRR/DANU/UNPO
To:	Hawari A; North Carolina State University
References
	50-297/24-001 50-297/OL-24
	Download: ML24052A120 (1)
	v • d • e

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-24-01, NORTH CAROLINA STATE UNIVERSITY

Dear Dr. Hawari:

During the week of May 13, 2024, the U.S. Nuclear Regulatory Commission (NRC) administered an operator licensing examination at your North Carolina State University Research Reactor. The examination was 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, 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-24-01

2. Written examination cc: w/enclosures to GovDelivery Subscribers May 29, 2024 Signed by Tate, Travis on 05/29/24

ML24052A120 NRR-079 OFFICE NRR/DANU/UNPO/CE NRR/DANU/UNPO/OLA NRR/DANU/UNPO/BC NAME ABeasten NJones TTate DATE 5/29/2024 5/29/2024 5/29/2024 U. S. NUCLEAR REGULATORY COMMISSION OPERATOR LICENSING INITIAL EXAMINATION REPORT REPORT NO.:

50-297/OL 24-01 FACILITY DOCKET NO.:

50-297 FACILITY LICENSE NO.:

R-120 FACILITY:

North Carolina State University EXAMINATION DATES:

Week of May 13, 2024 SUBMITTED BY:

SUMMARY

During the week of May 13, the NRC administered operator licensing examinations to one Senior Reactor Operator-Instant (SRO-I) candidate and four Reactor Operator (RO) candidates.

One RO candidate failed the operating test but passed the written examination. The remaining candidates passed all applicable portions of the examination.

REPORT DETAILS 1.

Examiner:

Amy E. Beasten, PhD, Chief Examiner, NRC 2.

Results:

RO PASS/FAIL SRO PASS/FAIL TOTAL PASS/FAIL Written 4/0 1/0 5/0 Operating Tests 3/1 1/0 4/1 Overall 3/1 1/0 4/1 3.

Exit Meeting:

Amy E. Beasten, PhD, Chief Examiner, NRC Timothy Ayers, Reactor Engineer, NRC Dr. Ayman Hawari, Director Nuclear Engineering Program Austin Wells, Engineer Anna Deeks, Reactor Health Physicist Prior to administration of the written exam, 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 examiners met with facility staff representatives to discuss the results and observations. At the conclusion of the meeting, the NRC examiners thanked the facility for their support in the administration of the examination.

Amy Beasten 5/16/2024 Name, Chief Examiner Date

North Carolina State University PULSTAR Reactor Operator Licensing Examination Week of May 13, 2024

U. S. NUCLEAR REGULATORY COMMISSION NON-POWER REACTOR LICENSE EXAMINATION FACILITY:

North Carolina State University Reactor REACTOR TYPE:

PULSTAR DATE ADMINISTERED:

May 16, 2024 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

U. S. NUCLEAR REGULATORY COMMISSION NON-POWER REACTOR LICENSE EXAMINATION FACILITY:

North Carolina State University Reactor REACTOR TYPE:

PULSTAR DATE ADMINISTERED:

May 16, 2024 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

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.

12.

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

Category A: Reactor Theory, Thermodynamics, & Facility Operating Characteristics A N S W E R S H E E T 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 _____ (0.25 each)

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 ___

A10 a b c d ___

A11 a b c d ___

A12 a b c d ___

A13 a _____ b _____ c _____ d _____ (0.25 each)

A14 a b c d ___

A15 a b c d ___

A16 a b c d ___

A17 a b c d ___

A18 a _____ b _____ c _____ d _____ (0.25 each)

A19 a b c d ___

A20 a b c d ___

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

Category B: Normal/Emergency Operating Procedures and Radiological Controls A N S W E R S H E E T 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 _____ (0.25 each)

B08 a b c d ___

B09 a b c d ___

B10 a b c d ___

B11 a b c d ___

B12 a _____ b _____ c _____ d _____ (0.50 each)

B13 a b c d ___

B14 a b c d ___

B15 a b c d ___

B16 a _____ b _____ c _____ d _____ (0.25 each)

B17 a b c d ___

B18 a b c d ___

B19 a _____ b _____ c _____ d _____ (0.25 each)

B20 a b c d ___

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

Category C: Facility and Radiation Monitoring Systems A N S W E R S H E E T 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 ___

C06 a b c d ___

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 _____ (0.25 each)

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 **********)

EQUATION SHEET

=

= 26.06

+

Gn,

=

+

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

2 2

max

P 1

sec 1.0

eff

2 1

1 1

2 1

eff eff K

CR K

CR

2 2

1 1

CR CR sec 10 1

4

eff K

S S

SCR

1

te P

P 0

)

(

0 10 t

SUR P

P 1

2 1

1 CR CR K

M eff

0 1

P P

2 1

1 1

eff eff K

K M

eff eff K

K SDM

1 2

1 1

2 eff eff eff eff K

K K

K

693

.0 2

1 T

eff eff K

K 1

2 2

1 1

d DR d

DR

t e

DR DR

0

1 2

2 2

Peak Peak

2 6

R n

E Ci DR

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

[1.0 point]

The figure below shows a trace of reactor period as a function of time. Which ONE of the following describes reactor power from point A to point C?

a.

Reactor power is constant.

b.

Reactor power is increasing, then stable.

c.

Reactor power is increasing continually.

d.

Reactor power is increasing, then decreasing, then stable.

QUESTION A.02

[1.0 point]

Which ONE of the following best describes inelastic scattering?

a.

A neutron is absorbed by the target nucleus to form a compound nucleus, which emits a neutron with lower kinetic energy, and the resulting excited state nucleus emits a gamma.

b.

A neutron is absorbed by the target nucleus to form a compound nucleus, which ejects an alpha particle or proton.

c.

A neutron is absorbed by the target nucleus to form a compound nucleus, which releases its excitation energy by emitting a gamma ray d.

d.

A neutron interacts with a target nucleus and momentum and kinetic energy are conserve.

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.03

[1.0 point, 0.25 each]

Match the decay mode in Column A with the definition in Column B. Answers in Column B may be used once, more than once, or not at all.

Column A a.

Alpha decay b.

Beta-minus decay c.

Beta-plus decay d.

Electron capture Column B 1.

Nucleus absorbs an electron from the innermost orbital, which combines with a proton to form a neutron.

2.

Conversion of a proton to a neutron and a positron, which is ejected from the nucleus.

3.

Conversion of a neutron to a proton and an electron, which is ejected from the nucleus.

4.

Emission of a helium atom from an unstable nucleus.

QUESTION A.04

[1.0 point]

Which ONE of the following defines eff?

a.

The fraction of neutrons at fast energies born as delayed neutrons.

b.

The average of the total delayed neutron fractions of the different types of fuel.

c.

The fraction of all fission neutrons born as delayed neutrons.

d.

The fraction of neutrons at thermal energies born as delayed neutrons.

QUESTION A.05

[1.0 point]

Which ONE of the following statements best describes integral rod worth?

a.

The reactivity change per unit movement of a rod.

b.

The total reactivity worth of the rod at a particular degree of withdrawal.

c.

The area under the curve represents the cumulative effect of withdrawing a control rod a specific distance from the core.

d.

The area under the curve represents the cumulative effect of withdrawing a control rod a specific rate from the core.

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.06

[1.0 point]

Which ONE of the following statements regarding fission with thermal neutrons is true?

a.

U-235 fissions with thermal neutrons because the binding energy released by the absorption of a neutron is less than the critical energy for fission.

b.

U-235 fissions with thermal neutrons because the binding energy released by the absorption of a neutron is greater than the critical energy for fission.

c.

U-238 fissions with thermal neutrons because the binding energy released by the absorption of a neutron is greater than the critical energy for fission.

d.

U-238 fissions with thermal neutrons because the binding energy released by the absorption of a neutron is less than the critical energy for fission.

QUESTION A.07

[1.0 point]

The current count rate is 300 cps. An experimenter inserts an experiment into the core and the count rate decreases to 170 cps. If the initial Keff was 0.895, what is the worth of the experiment?

a.

+ 0.110 b.

- 0.110 c.

+ 0.054 d.

- 0.054 QUESTION A.08

[1.0 point]

Which ONE of the following parameters is the MOST significant in determining the differential rod worth of a control rod?

a.

Flux shape b.

Rod speed c.

Reactor power d.

Fuel temperature

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.09

[1.0 point]

Which ONE of the following best explains the negative 80 second period following a reactor scram?

a.

The fuel temperature coefficient adding positive reactivity due to the fuel temperature decrease following a scram.

b.

Neutron population is sustained by decay of prompt neutrons.

c.

Neutron population is sustained by the decay of the longest-lived fission product precursor.

d.

Neutron population is sustained by decay of all delayed neutron precursors.

QUESTION A.10

[1.0 point]

As new fuel is being loaded into the core, the reactor operator is using a 1/M plot to monitor core loading. Which ONE of the following conditions could result in the reactor reaching criticality mass at a value greater than the predicted critical mass?

a.

The detector is located so that core load starts away from the detector and subsequent loading proceeds towards the detector.

b.

The detector is located so that core load starts at a point close to the detector and subsequent loadings move farther from the detector.

c.

Too much time elapses between subsequent core loadings.

d.

The detector and source are too close to each other.

QUESTION A.11

[1.0 point]

Which ONE of the following best describes the difference between moderators and reflectors?

a.

Moderators scatter neutrons to decrease leakage from the core and reflectors thermalize neutrons.

b.

Moderators scatter fast neutrons and reflectors scatter thermal neutrons.

c.

Moderators absorb thermal neutrons and reflectors scatter fast neutrons.

d.

Moderators thermalize neutrons and reflectors scatter neutrons to decrease leakage from the core.

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.12

[1.0 point]

Which ONE of the following best describes the effective multiplication factor, keff?

a.

The ratio of the number of thermal neutrons produced by fission in one generation to the number of thermal neutrons lost through leakage and absorption in the preceding generation.

b.

The ratio of the number of fast neutrons produced by fission in one generation to the number of fast neutrons lost through leakage and absorption in the preceding generation.

c.

The ratio of the number of total neutrons produced by fission in one generation to the number of neutrons lost through leakage and absorption in the preceding generation.

d.

The ratio of the number of total neutrons produced by fission in one generation to the number of neutrons lost through absorption in the preceding generation.

QUESTION A.13

[1.0 point, 0.25 each]

Match the isotope in Column A with the type of material in Column B. Options in Column B may be used once, more than once, or not at all.

Column A a.

Th-232 b.

U-233 c.

U-235 d.

U-238 Column B 1.

Fissile 2.

Fissionable 3.

Fertile QUESTION A.14

[1.0 point]

During a reactor startup, criticality occurred at a HIGHER rod height than the last startup. Which ONE of the following reasons could be the cause?

a.

Recent maintenance on the control rods resulted in a slightly slower rod speed.

b.

Fuel temperature increased.

c.

An experiment with positive reactivity was added to the core.

d.

An experiment with negative reactivity was added to the core.

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.15

[1.0 point]

What is the effective multiplication factor, given the source strength is 15,000 neutrons per second (N/sec) and it produces the stable neutron count rate of 75,000 N/sec?

a.

0.70 b.

0.75 c.

0.80 d.

0.85 QUESTION A.16

[1.0 point]

Which ONE of the following best describes the effect of Xe-135 on normal reactor operation?

a.

Xe-135 is inert and therefore has no impact on reactor operations.

b.

Xe-135 has a large mass which causes increased scattering collisions, slowing more neutrons to thermal energies as the concentration builds up over time.

c.

Xe-135 has a large thermal neutron absorption cross-section, which causes large removal of thermal neutrons from the core, causing negative reactivity addition.

d.

When Xe-135 is formed, kinetic energy in the form of heat is released, causing increases in moderator temperature and subsequently decreases in reactor power over the course of normal reactor operation.

QUESTION A.17

[1.0 point]

The following data was obtained during a reactor fuel load.

Step No. of Elements Detector A (count/sec) 1 0

100 2

4 120 3

8 140 4

12 200 5

15 400 The estimated number of additional elements required to achieve criticality is between:

a.

2 to 3 b.

4 to 5 c.

6 to 7 d.

8 to 10

Category A: Reactor Theory, Thermodynamics, and Facility Operating Characteristics QUESTION A.18

[1.0 point, 0.25 each]

Complete the decay chain below by matching the blanks in Column A with the isotopes listed in Column B. Answers in Column B may be used once, more than once, or not at all.

19 0 1+ 6.57 0 1+ 135 54 69.1 0

1+ 2.3E6 0 1+ (stable)

Column A a.

A b.

B c.

C d.

D Column B 1.

135 55 Cs 2.

135 56 Ba 3.

135 52 Te 4.

135 53 I QUESTION A.19

[1.0 point]

What is the condition of the reactor when =

1 1 eff?

a.

Prompt critical b.

Critical c.

Supercritical d.

Subcritical QUESTION A.20

[1.0 point]

Which ONE of the following best describes the difference between prompt and delayed neutrons?

a.

Prompt neutrons are produced immediately and directly from the fission event and delayed neutrons are produced immediately following the first beta decay of fission fragments.

b.

Prompt neutrons are produced from spontaneous fission of U-235 in the fuel, and delayed neutrons are the result of fission in U-238.

c.

Prompt neutrons are responsible for the ability to control the rate at which power can rise in the reactor and delayed neutrons are responsible for the rate at which a reactor can be shut down.

d.

Prompt neutrons ensure there is a sufficient neutron population to overcome the effects of fission product poisoning following a shutdown and delayed neutrons are responsible for lengthening the neutron generation time to ensure the reactor does not go prompt critical.

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

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

[1.0 point]

What is the dose rate at 1 foot, given 80% of the decay of a 5 Curie source results in emission of a 250 keV gamma?

a.

0.6 R/hr b.

6.0 R/hr c.

60 R/hr d.

600 R/hr QUESTION B.02

[1.0 point]

In accordance with NRP-OP-101, Reactor Startup and Shutdown, which ONE of the following reactivity affecting parameters factors does not have an effect on the estimated critical position (ECP)?

a.

Location and reactivity of experiments in the core.

b.

Moderator temperature.

c.

Startup source location.

d.

Fuel temperature.

QUESTION B.03

[1.0 point]

In accordance with the PULSTAR Emergency Plan, which ONE of the following individuals has the authority to terminate an emergency?

a.

Emergency Operations Manager.

b.

Emergency Coordinator.

c.

Emergency Director.

d.

Emergency Team Lead.

QUESTION B.04

[1.0 point]

The radiation from an unshielded source is 500 mrem/hr. A 30-mm thick lead sheet is inserted and the radiation level drops to 150 mrem/hr. What is the half-value-layer (HVL) of lead?

a.

17.3 mm b.

24.9 mm c.

34.6 mm d.

52.1 mm

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.05

[1.0 point]

In accordance with NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions, which ONE of the following best describes the visible light indications on the console following a reactor scram?

a.

The green ROD SEATED, the red SCRAM, and the red SCRAM INPUT light are on.

The red OFF MAGNET and green MAGNET POWER light are off.

b.

The green ROD SEATED, red OFF MAGNET, the red SCRAM, and the red SCRAM INPUT light are on.

The green MAGNET POWER light is off.

c.

The green ROD SEATED, the green MAGNET POWER, the red SCRAM, and the red SCRAM INPUT light are on.

The red OFF MAGNET light is off.

d.

The red SCRAM, and the red SCRAM INPUT light are on.

The green ROD SEATED, red OFF MAGNET, and the green MAGNET POWER lights are off.

QUESTION B.06

[1.0 point]

In accordance with NRP-OP-301, Reactor Fuel Handling, which ONE of the following statements best describes the reason the control rods need to be cocked during fuel movement?

a.

To ensure shutdown margin is known prior to commencing fuel movement such that the reactor will remain subcritical upon all fuel movements and/or loading.

b.

To ensure that the control rods have at least 400 pcm to shutdown the reactor.

c.

To ensure sufficient moderation by the water and reflectors to keep the reactor subcritical during all fuel movements and/or loading.

d.

To facilitate fuel assembly worth determinations prior to fuel movements and/or loading.

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.07

[1.0 point, 0.25 each]

Match the Technical Specification required surveillance in Column A with the surveillance frequency in Column B. Options in Column B may be used once, more than once, or not at all.

Column A a.

Visual inspection of control rods b.

Channel calibration of pool water level monitor c.

Determination of excess reactivity d.

Calibration of control room differential pressure gauges Column B 1.

Monthly 2.

Semi-annually 3.

Annually 4.

Biennially QUESTION B.08

[1.0 point]

In accordance with NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions, all of the following actions should be taken in the event of a fire EXCEPT:

a.

Scram the reactor.

b.

Initiate confinement mode.

c.

Secure the Secondary System.

d.

Attempt to fight the fire.

QUESTION B.09

[1.0 point]

In accordance with 10 CFR 20, individual members of the public are limited to a dose in an unrestricted area from an external source:

a.

0.2 mrem/hr.

b.

2 mrem/hr.

c.

100 mrem/hr.

d.

500 mrem/hr.

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.10

[1.0 point]

All of the following are defined as abnormal reactivity changes in accordance with NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions, EXCEPT:

a.

An unanticipated step change in reactor power during critical operation resulting in the spontaneous generation of a short reactor period or a change in reactivity greater the eff.

b.

Actual Critical Position (ACP) which is not within +/-200 pcm of the Estimated Critical Position (ECP).

c.

An unanticipated reactivity change of 50 pcm, requiring notification of the Duty Senior Reactor Operator (DSRO).

d.

A significant variation in the reactivity value of an experiment from that which was anticipated.

QUESTION B.11

[1.0 point]

The exposure rate for a point source is 525 mR/hr at a distance of 4 meters. What is the exposure rate at a distance of 8 meters?

a.

32.8 mR/hr b.

131 mR/hr c.

262 mR/hr d.

2100 mR/hr QUESTION B.12

[1.0 point]

In accordance with PULSTAR Technical Specifications, which ONE of the following conditions is NOT permissible while the reactor is operating?

a.

Reactor coolant inlet temperature at 120°F.

b.

Pool water level at 14 feet 4 inches.

c.

Primary coolant flow rate is 480 gpm.

d.

A single non-secured experiment has a reactivity of 900 pcm.

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.13

[1.0 point]

All of the following are true statements regarding PULSTAR Technical Specification surveillance requirements EXCEPT:

a.

Some system tests may be postponed at the required intervals if that system or a closely associated system is undergoing maintenance.

b.

Surveillance requirements scheduled to occur during extended operation which cannot be performed while the reactor is operating may be deferred until the next planned reactor shutdown.

c.

Surveillance requirements that require reactor operation must be performed immediately after the reactor restarts.

d.

If it is desired to permanently change the scheduled date of surveillance, the particular surveillance item may be performed at a later date as allowed by the interval tolerance.

QUESTION B.14

[1.0 point]

You are currently a licensed operator at the PULSTAR reactor. Which ONE of the following conditions would be a violation of 10 CFR 55.53, Conditions of licenses?

a.

Your last requalification operational examination was 13 months ago.

b.

Your last medical exam was 16 months ago.

c.

Last quarter, you were the licensed operator for 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

d.

The new requalification program cycle started 12 months ago.

QUESTION B.15

[1.0 point]

In accordance with the PULSATR Emergency Plan, all of the following events would be classified as Notifications of Unusual Events EXCEPT:

a.

Bomb threat affecting the facility.

b.

Tornado affecting the facility.

c.

Control room radiation monitor reading 5 mrem/hr.

d.

Fire affecting the facility which cannot be extinguished within 15 minutes.

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.16

[1.0 point, 0.25 each]

Match the definition in Column A with the term in Column B. Options in Column B may be used once, more than once, or not at all.

Column A a.

The sum of the effective dose equivalent for external exposures and the committed effective dose equivalent for internal exposure.

b.

The dose equivalent at a tissue depth of 1.

c.

The dose equivalent to organs or tissues that will be received from an intake of radioactive material by an individual over a 50-year period following intake cm.

d.

The derived limit for the amount of radioactive material taken into the body by inhalation or ingestion in a year.

Column B 1.

Committed Dose Equivalent (CDE) 2.

Total Effective Dose Equivalent (TEDE) 3.

Annual Limit on Intake (ALI) 4.

Deep-Dose Equivalent (Hd)

QUESTION B.17

[1.0 point]

In accordance with the PULSTAR emergency plan, all of the following statements regarding reactor building evacuation are true EXCEPT:

a.

Non-essential personnel in the control room will evacuate to the BEL.

b.

Essential personnel shall report to the control room and remain there if habitability requirements are met.

c.

Non-essential personnel in the reactor bay shall evacuate through the northwest door and assemble in the change room.

d.

All personnel in the reactor building shall evacuate through the nearest exit and assemble outside the North entrance of the BEL.

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.18

[1.0 point]

In accordance with 10 CFR 50.54(x), a licensee may take reasonable action that departs from a license condition or technical specification in an emergency when this action is immediately needed to protect the public health and safety. Which ONE of the following individuals may authorize this action?

a.

A licensed Senior Reactor Operator.

b.

NBSU Health Physicist.

c.

A licensed Reactor Operator.

d.

Manager of Engineering and Operations.

QUESTION B.19

[1.0 point, 0.25 each]

Match the function in Column A with the definition in Column B. Options in Column B may be used once, more than once, or not at all.

Column A a.

Comparison of Power Range Linear Power indications with Wide Range Log Power indications of reactor power b.

Adjustment of Wide Range Log Power channel indications following performance of the thermal power calibration to correct for acceptable instrument drift c.

Verification of correct indication on the N-16 channel by raising reactor power to a known setpoint d.

Comparison of current Wide Range Log Power channel indications with Wide Range Log Power indications at the same reactor power levels during previous operations Column B 1.

Channel Check 2.

Channel Test 3.

Channel Calibration

Category B: Normal/Emergency Operating Procedures and Radiological Controls QUESTION B.20

[1.0 point]

In accordance with PULSTAR Technical Specifications, the Radiation Safety Committee (RSC) has all of the following review and approval functions EXCEPT:

a.

Proposed changes to the facility Technical Specifications.

b.

New experiments or classes of experiments which could result in a release of radioactivity.

c.

Any operations that result in a violation of Technical Specifications.

d.

Proposed changes to facility equipment which have been determined to meet facility license and/or Technical Specification requirements.

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

Category C: Facility and Radiation Monitoring Systems QUESTION C.01

[1.0 point]

Which ONE of the following best describes the safety rod drive assembly?

a.

The safety rod drive assembly consists of an electromechanical drive, with a stepper motor, magnetic rod coupler, and rack-and-pinion gear system.

b.

The safety rod drive assembly consists of an electromagnetically coupled motor, gear reduction system, and an acme screw type drive.

c.

The safety rod drive assembly consists of two 2-phase electric servo motors in parallel driving a lead-screw nut combination.

d.

The safety rod drive assembly consists of a large compression spring with a ball nut and screw jack.

QUESTION C.02

[1.0 point]

Which ONE of the following statements best describes the flow of primary coolant during natural convection mode of operation?

a.

The primary pump is in slow-speed operation, which causes a drop in forced flow through the core causing a loss of differential pressure across the flapper valve, which closes via gravity. Water flows around the closed flapper valve and flows down through the core.

b.

The primary pump is in slow-speed operation, which causes a drop in forced flow through the core causing a loss of differential pressure across the flapper valve, which falls open due to gravity. Water flows through the open flapper valve and up through the core.

c.

The primary pump is secured and the loss of forced flow through the core causes a loss of differential pressure across the flapper valve, which falls open due to gravity. Water flows through the open flapper valve and up through the core.

d.

The primary pump is secured and the loss of forced flow through the core causes a loss of differential pressure across the flapper valve, which closes due to gravity. Water bypasses the closed flapper valve and flows down through the core.

QUESTION C.03

[1.0 point]

In accordance with facility Technical Specifications, during periods of repair or maintenance on

___________ (not to exceed 90 days), specified area and effluent monitor readings shall be manually recorded at a nominal interval of _______ when the reactor is not shutdown.

a.

The stack gas monitor; 60 minutes.

b.

Any fixed area monitor; 30 minutes.

c.

The Over-the-pool monitor; 60 minutes.

d.

The Radiation Rack Recorder; 30 minutes.

Category C: Facility and Radiation Monitoring Systems QUESTION C.04

[1.0 point]

During full power operations with both the primary and secondary pumps in service, all of the following could be indications of a leak inside the heat exchanger EXCEPT:

a.

Decreasing pool level b.

Increase in radiation levels c.

Increase in resistivity measurements across the demineralizer d.

Presence of Na-24 QUESTION C.05

[1.0 point]

All of the following statements about the control rod reverse drive function are true EXCEPT:

a.

The Reverse drive is initiated when power indications on the Linear Channel reach 110%.

b.

The Reverse drive is generated on scram signals to ensure the rods fully seat.

c.

The Reverse drive will automatically drive the safety rods 1 and 2 and the regulating rod towards the full in position until the ACKNOWLEDGE pushbutton is pressed.

d.

The Reverse drive will automatically drive the safety rods 1 and 2 towards the full in position until the ACKNOWLEDGE pushbutton is pressed. If the Regulating Rod is in automatic, the rod will not move.

QUESTION C.06

[1.0 point]

Which ONE of the following best describes the reason for the high sensitivity of a Geiger-Mueller detector?

a.

The lower voltage applied to the detector helps to amplify all incident events.

b.

It is coated with special nuclear material that causes high ionizations at low concentrations.

c.

Any incident radiation event causing primary ionization results in ionization of the entire detector.

d.

It has a large tube, so the target area is bigger for all incident events.

Category C: Facility and Radiation Monitoring Systems QUESTION C.07

[1.0 point]

Which ONE of the following best describes how the Source Range Channel functions?

a.

The Source Range Channel is a fission chamber lined with highly enriched U-238. Neutrons interact with the U-238 to produce fission, which ionize the fill gas. Gammas also ionize the fill gas. At low powers, the circuitry uses a pulse height discriminator to differentiate the neutrons from the gammas to provide an indication of reactor power.

b.

The Source Range Channel is a fission chamber lined with B-10. Neutrons fission with the B-10 to produce alpha particles which ionize the gas. Gammas also ionize the fill gas. The combined signal provides an indication of reactor power.

c.

The Source Range Channel is a fission chamber lined with highly enriched U-235. Neutrons interact with the U-235 to produce fission, which ionize the fill gas. Gammas also ionize the fill gas. At low powers, the circuitry uses a pulse height discriminator to differentiate the neutrons from the gammas to provide an indication of reactor power.

d.

The Source Range Channel is a dual fission chamber, with one chamber filled with BF3 gas and the other filled with an inert gas. Neutrons fission with the Boron to produce alpha particles which ionize the gas. Gammas also ionize the fill gases in both chambers. The gamma signal is subtracted from the neutron signal to provide an indication of reactor power over the full range of operation.

QUESTION C.08

[1.0 point]

Which ONE of the following materials constitutes the primary coolant system piping?

a.

Stainless Steel b.

Carbon Steel c.

Aluminum d.

PVC

Category C: Facility and Radiation Monitoring Systems QUESTION C.09

[1.0 point]

Which ONE of the following statements correctly describes the Safety Channel trip circuits?

a.

Trip #1 prevents automatic channel operation when the demand potentiometer setting exceeds actual reactor power by more than +/-9%. Trip #2 produces an Overpower scram at 120%.

b.

Trip #1 prevents automatic channel operation when the demand potentiometer setting exceeds actual reactor power by more than +/-9%. Trip #2 produces an reverse signal at 110%.

c.

Trip #1 enables the Low Primary Flow and Flapper Open scram circuits to produce an automatic scram when power levels exceed 150kW with no primary coolant flow. Trip #2 produces a reverse signal at 110%.

d.

Trip #1 enables the Low Primary Flow and Flapper Open scram circuits to produce an automatic scram when power levels exceed 150kW with no primary coolant flow. Trip #2 produces an Overpower scram at 120%.

QUESTION C.10

[1.0 point]

Which ONE of the following statements describes the purpose of the < 2cps control rod inhibit on the source range channel?

a.

This inhibit ensures that the reactor period reading is on scale prior to raising power from the Estimated Critical Position.

b.

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

c.

This inhibit ensures that the source range channel is reading is on scale prior to initiating startup.

d.

This inhibit ensures that following periods of extended operation, the number of neutrons produced directly from fission are greater than the fission events resulting from neutron poisons remaining in the core.

Category C: Facility and Radiation Monitoring Systems QUESTION C.11

[1.0 point]

Which ONE of the following statements best describes the normal flow path of air through the facility ventilation system?

a.

Air from the Reactor Bay is drawn through the exhaust plenum where it passes through a prefilter and a main filter. The air is discharged to the atmosphere through the stack via the main exhaust fan.

b.

Air from the Reactor Bay is drawn through the exhaust plenum where it passes through a charcoal absorber and a HEPA filter. The air is discharged to the atmosphere through the stack via the main exhaust fan.

c.

Air from the Reactor Bay is drawn through the exhaust plenum where it passes through a prefilter and a main filter. The air is discharged to the atmosphere through the stack via a pair of confinement exhaust fans.

d.

Air from the Reactor Bay is drawn through the exhaust plenum where it passes through a charcoal absorber and a HEPA filter. The air is discharged to the atmosphere through a pair of confinement exhaust fans.

QUESTION C.12

[1.0 point]

Which ONE of the following statements best describes the construction and operation of the facility N-16 Channel?

a.

The N-16 detector is an energy compensated Geiger Mueller detector mounted on the 10-inch primary coolant cold leg. It indicates relative radiation levels caused by the decay of N-16 gammas produced during normal operation.

b.

The N-16 detector is an uncompensated ion chamber mounted on the 10-inch primary coolant hot leg. It indicates reactor power level as a function of the decay of N-16 gammas produced during normal operation.

c.

The N-16 detector is a gas-filled gamma sensitive ionization chamber mounted on the 10-inch primary coolant hot leg. It indicates reactor power level as a function of the decay of N-16 gammas produced during normal operation.

d.

The N-16 detector is a scintillation chamber mounted on the 10-inch primary coolant hot leg.

It indicates primary coolant flow rate as a function of the decay of N-16 gammas produced during normal operation.

Category C: Facility and Radiation Monitoring Systems QUESTION C.13

[1.0 point]

Which ONE of the following statements best describes the flow of primary coolant through the cleanup loop?

a.

20 gpm of coolant is suctioned off the primary coolant cold leg and passes through the demineralizer, then through a 25 micron filter and returns to the primary coolant cold leg, where it flows into the tank.

b.

20 gpm of coolant is suctioned off the primary coolant hot leg and passes through a 25 micron filter to the demineralizer, then through a second 25 micron filter and returns to the primary coolant hot leg after the heat exchangers, where it flows into the tank.

c.

20 gpm of coolant is suctioned off the primary coolant cold leg and passes through a 25 micron filter to the demineralizer, then through a second 25 micron filter and returns to the primary coolant cold leg, where it flows into the tank.

d.

20 gpm of coolant is suctioned off the primary coolant cold leg and passes through the demineralizer, then through a 25 micron filter and returns to the primary coolant cold leg, where it flows into the tank.

QUESTION C.14

[1.0 point, 0.25 each]

In accordance with Technical Specifications, if one confinement filter train is taken out of service for repair or maintenance, how often must the standby filter train be verified operable, if the reactor is operating in normal ventilation mode?

a.

Every 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months b.

Weekly c.

Daily d.

Hourly QUESTION C.15

[1.0 point]

All of the following statements regarding the automatic mode of operation are true EXCEPT:

a.

A deviation between the actual reactor power and the flux controller of 10% will cause automatic mode to disengage.

b.

The gang drive switch must be in the neutral position for automatic mode to be engaged.

c.

The Automatic Channel flux controller is the Log Monitor power demand potentiometer.

d.

Automatic control is allowed with the CRDM on the regulating rod is withdrawn beyond 13.5 inches rod height.

Category C: Facility and Radiation Monitoring Systems QUESTION C.16

[1.0 point, 0.25 each]

Match the Radiation Area Monitor in Column A with the ALARM setpoint in Column B. Options in Column B may be used once, more than once, or not at all.

Column A a.

Stack particulate monitor b.

West Wall monitor c.

Control Room monitor d.

Continuous Air Monitor Column B 1.

1 DAC fraction 2.

5 mR/hr 3.

100 mR/hr 4.

5,000 Co-60 AEC QUESTION C.17

[1.0 point]

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

a.

H-3; produced from the irradiation of water b.

Xe-135; produced as a byproduct of fission c.

N-16; produced from irradiation of water d.

O-19; produced from irradiation of air QUESTION C.18

[1.0 point]

Which ONE of the following statements correctly describes the series of events that occur upon a loss of commercial power to the facility?

a.

The generator automatically starts, the load transfer switches CLOSE and the generator contacts CLOSE. Power is supplied from the load transfer switches to the control room distribution panel and both confinement fans.

b.

The generator automatically starts, the load transfer switches OPEN and the generator contacts OPEN. Power is supplied from the generator to the control room distribution panel and both confinement fans, although only one can operate at a time.

c.

The generator automatically starts, the load transfer switches CLOSE and the generator contacts OPEN. Power is supplied from the load transfer switches to the control room distribution panel and both confinement fans.

d.

The generator automatically starts, the load transfer switches OPEN and the generator contacts CLOSE. Power is supplied from the generator to the control room distribution panel and both confinement fans, although only one can operate at a time.

Category C: Facility and Radiation Monitoring Systems QUESTION C.19

[1.0 point]

In accordance with Technical Specifications, which ONE of the following statements best describes the reason for limiting pool water temperature below 120°F?

a.

The pool water temperature limit provides for shutdown of the reactor and prevents exceeding the Safety Limit due to high pool water temperature.

b.

The pool water temperature limit provides alarm indication that is administrative in nature for the initiation of normal pool water makeup to prevent pool level from lowering due to evaporation.

c.

The pool water temperature limit provides for shutdown of the reactor to prevent the resin in the demineralizer tanks from being degraded.

d.

The pool water temperature limit provides alarm indication for the reactor operator to initiate secondary cooling to prevent damage to facility equipment and components resulting from elevated pool temperatures.

QUESTION C.20

[1.0 point]

All of the following experimental locations discharge air to the exhaust plenum EXCEPT:

a.

Beam tubes b.

Thermal column c.

Rotating exposure ports d.

Pneumatic transfer system

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

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

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

c.

Reference:

Reactor power keeps increasing because period is positive.

CR1 / CR2 = (1 - Keff2) / (1 - Keff1) 170 / 300 = (1 - Keff2) / (1 - 0.895)

Therefore Keff2 = 0.815

= (Keff2 - Keff1) / (Keff2

Keff1)

= (0.815 - 0.895) / (0.815

0.895)

= - 0.110 A.08 Answer:

a.

Reference:

Burn, Introduction to Nuclear Reactor Operations, Section 7, page 7-4 A.09 Answer:

c.

Reference:

Reed Robert Burn, Introduction to Nuclear Reactor Operations, Volume 2, Section 4.5, p 4-12 A.10 Answer:

b.

Reference:

Burn, Section 5.5, p. 5-18 A.11 Answer:

d.

Reference:

Burn, Introduction to Nuclear Reactor Operations, Section 2.7, 2-63

DOE Fundamentals Handbook, Vol. 1, p. 29

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

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

b.

Reference:

6 Cen = R/hr at 1 ft (6 x 5 Ci) x (0.8

0.25) 0.96 R/hr at 1 ft B.02 Answer:

d.

Reference:

NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions

10 CFR 50.54(x) and 50.54(y)

B.19 Answer:

a. 1 (Channel Check); b. 3 (Channel Calibration); c. 2 (Channel Test); d. 1 (Channel Check)

Reference:

PULSTAR Technical Specifications 1.2.2, 1.2.3, 1.2.4 B.20 Answer:

d.

Reference:

PULSTAR Technical Specifications 6.2.3 (RSAC has review and approval of d)

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

Reference:

PULSTAR SAR 9.1, 10.2

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

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

ML24052A120

Text

SUBJECT:

Dear Dr. Hawari:

Enclosures:

SUMMARY

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