ML082750036

Initial Examination Report No. 50-20/OL-08-01, Massachusetts Institute of Technology

ML082750036
Person / Time
Site:	MIT Nuclear Research Reactor
Issue date:	10/20/2008
From:	Johnny Eads Research and Test Reactors Branch B
To:	Bernard J Massachusetts Institute of Technology (MIT)
Young P, NRC/NRR/ADRA/DPR, 415-4094
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ml081620279	List: ML082750025 ML082750036
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50-20/OL-08-01
Download: ML082750036 (29)

Text

October 20, 2008 Dr. John A. Bernard, Jr.

Director of Reactor Operations Massachusetts Institute of Technology Research Reactor MITNRL-NW 12 138 Albany Street Cambridge, MA 02139

SUBJECT:

INITIAL EXAMINATION REPORT NO. 50-20/OL-08-01, MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Dear Dr. Bernard:

During the week of September 1, 2008, the NRC administered an operator licensing examination at your Massachusetts Institute of Technology 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 (PARS) component of NRC's Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site 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 Mr. Phillip T. Young at 301-415-4094 or via internet e-mail pty@nrc.gov.

Sincerely,

/RA/

Johnny H. Eads, Jr., Chief Research and Test Reactors Branch B Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Docket No. 50-20

Enclosures:

1. Initial Examination Report No. 50-20/OL-08-01

2. Written examination with facility comments incorporated cc without enclosures: See next page

October 20, 2008 Dr. John A. Bernard, Jr.

Director of Reactor Operations Massachusetts Institute of Technology Research Reactor MITNRL-NW 12 138 Albany Street Cambridge, MA 02139

SUBJECT:

INITIAL EXAMINATION REPORT NO. 50-20/OL-08-01, MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Dear Dr. Bernard:

During the week of September 1, 2008, the NRC administered an operator licensing examination at your Massachusetts Institute of Technology 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 (PARS) component of NRC's Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site 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 Mr. Phillip T. Young at 301-415-4094 or via internet e-mail pty@nrc.gov.

Sincerely,

/RA/

Johnny H. Eads, Jr., Chief Research and Test Reactors Branch B Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Docket No. 50-20

Enclosures:

1. Initial Examination Report No. 50-20/OL-08-01

2. Written examination with facility comments incorporated cc without enclosures: See next page DISTRIBUTION w/ encls.:

PUBLIC PRTB r/f RidsNRRDPRPRTA RidsNRRDPRPRTB Facility File (CHart) O-13 D-07 ADAMS ACCESSION #: ML082750036 TEMPLATE #:NRR-074 OFFICE PRTB:CE IOLB:LA E PRTB:SC NAME PYoung pty CRevelle cr JEads jhe DATE 10/04/08 10/10/08 10/20/08 OFFICIAL RECORD COPY

Massachusetts Institute of Technology Docket No. 50-20 cc:

City Manager City Hall Cambridge, MA 02139 Department of Environmental Protection One Winter Street Boston, MA 02108 Director Radiation Control Program Department of Public Health 90 Washington Street Dorchester, MA 02121 Nuclear Preparedness Manager Massachusetts Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399 Test, Research, and Training Reactor Newsletter University of Florida 202 Nuclear Sciences Center Gainesville, FL 32611

U. S. NUCLEAR REGULATORY COMMISSION OPERATOR LICENSING INITIAL EXAMINATION REPORT REPORT NO.: 50-20/OL-08-01 FACILITY DOCKET NO.: 50-20 FACILITY LICENSE NO.: R-37 FACILITY: MITR-II EXAMINATION DATES: September 02 - 04, 2008 SUBMITTED BY: _________/RA/_____________ 10/4/08 Phillip T. Young, Chief Examiner Date

SUMMARY

During the week of September 1, 2008 the NRC administered operator licensing examinations to one Reactor Operator applicant and four Senior Operator applicants. All applicants passed all portions of the examinations.

REPORT DETAILS

1. Examiners:

Phillip T. Young, Chief Examiner, NRC

2. Results:

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

3. Exit Meeting:

Phillip T. Young, NRC, Examiner Mr. Ed Lau, MIT, Reactor Superintendent Mr. Frank Warmsley, MIT, Training Supervisor The examiner thanked the facility for all the work and coordination required to conduct the examinations.

ENCLOSURE 1

US NRC License Operator Examination MASSACHUSETTS INSTITUTE OF TECHNOLOGY Operator Written Examination with Answer Key September 02, 2008 ENCLOSURE 2

Hi Phillip, This is Frank Warmsley from the MIT Nuclear Reactor Lab.

Below are the 3 questions that had incorrect answers from the exam you administered at the facility.

FACILITY COMMENT Question C.006 The question had to do with the expected response of the ventilation system. The answer key had A, the ventilation would trip due to low temperature of the outside air. It is not the outside air that would cause a trip, it is the air after going through the preheating system that would cause a trip.

The correct answer is D, that the dampers in weekend open position would close on receipt of a high level signal.

NRC RESPONSE Facility comment accepted, answer key changed to reflect d. As the correct answer.

FACILITY COMMENT Question C.010 The next 2 problems are to be found in the multiple choice question where the question said to assume the reactor is critical. The 2 questions you have marked the answers as 2, rod withdrawal prohibited, are actually 1, no system response. This is because the question stated that the reactor was already critical, hence the blades are already withdrawn.

NRC RESPONSE Facility comment accepted, answer key changed for parts a. And d. To reflect 1 as the correct answer..

Frank Warmsley Training Supervisor MIT Nuclear Reactor Lab

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 1 of 29 Question A.001 [1.0 point] (1.0)

Given the following condition, which reactor would go critical first? (All other conditions are identical.)

a. Reactor with a blade withdrawal speed of 1 inch per minute.

b. Reactor with a blade withdrawal speed of 4 inches per minute.

c. Reactor with a blade withdrawal speed of 6 inches per minute.

d. Reactor with a blade withdrawal speed of 9 inches per minute.

Answer: A.001 d.

Reference:

Reactor Physics Notes "Reactor Subcritical Multiplication" Question A.002 [1.0 point] (2.0)

The void coefficient for the MIT reactor (core center) is?

a. 0.02 mbeta/cm3

b. 0.2 mbeta/cm3

c. 2 mbeta/cm3

d. 20 mbeta/cm3 Answer: A.002 c.

Reference:

RSM 10.8 Question A.003 [1.0 point] (3.0)

After a week of full power operation, Xenon will reach its peak following shutdown in approximately:

a. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />

b. 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />

c. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />

d. 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> Answer: A.003 a.

Reference:

MIT Reactor Physics Notes, Reactivity Feedback and measurement of a Xenon Transient; RSM 10.6

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 2 of 29 Question A.004 [1.0 point] (4.0)

A subcritical reactor is being started up. A control rod (shim blade) is raised in four equal steps (inches). Which statement most accurately describes the expected reactor response?

a. Each withdrawal will add the same amount of reactivity.

b. Power increases by the same amount for each withdrawal.

c. The time for power to stabilize after each successive withdrawal increases.

d. A lower critical rod height is attained by decreasing the time intervals between withdrawals.

Answer: A.004 c.

Reference:

MIT Reactor Physics Notes, Reactor Startup and Subcritical Multiplication Question A.005 [1.0 point] (5.0)

A control rod is withdrawn until 100 millibeta is added to a critical reactor.

Which ONE of the following will be the expected reactor period immediately after rod motion stops? (Assume delayed neutron decay constant is 0.1 s-1)

a. 30 second

b. 45 second

c. 90 second

d. 110 second Answer: A.005 c.

Reference:

T = (B-p)/(lambda x p); T= (1-0.1)/(0.1x0.1); T=90s Question A.006 [1.0 point] (6.0)

Shortly after a reactor trip, reactor power indicates 0.5% where a stable negative period is attained. Reactor power will be reduced to 0.05% in approximately _______ seconds.

a. 90

b. 180

c. 270

d. 360 Answer: A.006 b.

Reference:

Glasstone, S. and Sesonske, A, Nuclear Reactor Engineering, Kreiger Publishing, Malabar, Florida, 1991, § 5.47, p. 246.

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 3 of 29 Question A.007 [1.0 point] (7.0)

An initial count rate of 100 is doubled five times during startup. Assuming an initial Keff = 0.950, what is the new Keff?

a. 0.957

b. 0.979

c. 0.988

d. 0.998 Answer: A.007 d.

Reference:

Glasstone, S. and Sesonske,§ 3.161 3.163, pp. 190 191.

(1/32 (1 - 0.95) = 1 - Keff2) (1 - 0.05/32 = Keff2) Keff2 = 0.9984 Question A.008 [1.0 point] (8.0)

Which one of the following is the MAXIMUM amount of reactivity that can be promptly inserted into the reactor WITHOUT causing the reactor to go "Prompt Critical"?

a. 100 m

b. 500 m

c. 750 m

d. 1900 m Answer: A.008 c.

Reference:

Glasstone, S. and Sesonske, § 5.55, p. 250.

k = 1 / (1- ) k = 1 when =

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 4 of 29 Question A.009 [1.0 point] (9.0)

Which statement illustrates a characteristic of Subcritical Multiplication?

a. As Keff approaches unity (1), for the same increase in Keff, a greater increase in neutron population occurs.

b. The number of neutrons gained per generation gets larger for each succeeding generation.

c. The number of fission neutrons remain constant for each generation.

d. The number of source neutrons decreases for each generation.

Answer: A.009 a.

Reference:

Glasstone, S. and Sesonske, §§ 3.161 3.163, pp. 190 191.

Question A.010 [1.0 point] (10.0)

An experiment to be placed in the central thimble has been wrapped in cadmium. Which one of the following types of radiation will be most effectively blocked by the cadmium wrapping?

a. Thermal neutrons

b. Fast neutrons

c. Gamma rays

d. X-rays Answer: A.010 a.

Reference:

Glasstone, S. and Sesonske, 1991, § 10.34, pp. 639.

Question A.011 [1.0 point] (11.0)

Assuming the Samarium worth is 0.006 K/K at full power, which one of the following is the Samarium worth 10 days after shutdown from full power?

a. Essentially zero.

b. It increases by a factor of 2.

c. Less than 0.006 K/K but greater than zero.

d. Greater than 0.006 K/K Answer: A.011 d.

Reference:

Glasstone, S. and Sesonske, § 5.81 5.83, p. 260.

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 5 of 29 Question A.012 [1.0 point] (12.0)

How does shim bank position relate to the reactivity worth of dumping the D2O reflector?

a. For the lowest shim bank position, the reactivity worth of a D2O dump is at its greatest.

b. For the highest shim bank position, the reactivity worth of a D2O dump is at its greatest.

c. For the intermediate shim bank position, the reactivity worth of a D2O dump is at its greatest.

d. For the intermediate shim bank position, the reactivity worth of a D2O dump is at its minimum.

Answer: A.012 b.

Reference:

RSM 10-7 Question A.013 [1.0 point] (13.0)

How will raising the temperature of the water in the core and the heavy water in the shield affect reactivity?

Light Water Heavy Water

a. Positive Negative

b. Positive Positive

c. Negative Negative

d. Negative Positive Answer: A.013 c.

Reference:

RSM 10-8 Question A.014 [1.0 point] (14.0)

What is the definition of reactivity?

a. A measure of the number of neutrons being produced in the core.

b. A measure of the number of neutrons being absorbed by the fuel.

c. A measure of the reactors departure from critical.

d. A measure of the reactors multiplication factor.

Answer: A.014 c.

Reference:

MITR II Reactor Physics Notes - Reactor Kinetics

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 6 of 29 Question A.015 [1.0 point] (15.0)

On average, how many neutrons will be emitted per fission from the MITR-II core?

a. 3

b. 2.5

c. 2

d. 1.5 Answer: A.015 b.

Reference:

MITR II Reactor Physics Notes - Reactor Startup and Subcritical Multiplication (2)

Question A.016 [1.0 point] (16.0)

What is the kinetic energy range of a thermal neutron?

a. > 1 MeV

b. 100 KeV - 1 MeV

c. 1 eV - 100 KeV

d. < 1 eV Answer: A.016 d.

Reference:

Glasstone, S., Nuclear Reactor Engineering, Kreiger Publishing, Malabar: Florida, 1991. 3rd Edition. pg. 13 Question A.017 [1.0 point] (17.0)

What is the normal MITR-II neutron startup source for a startup when the reactor has only been shut down for a few hours?

a. Spontaneous fission from Cf252

b. Beta produced from Ra results in a neutron from Li8

c. Alpha produced from Po results in a neutron from Be9

d. Gamma produced from fuel results in a neutron from H2 Answer: A.017 d.

Reference:

MITR II Reactor Physics Notes - Reactor Startup and Subcritical Multiplication

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 7 of 29 Question A.018 [1.0 point] (18.0)

What are the advantages/disadvantages of using light water as compared to heavy water as a moderator or reflector? Light water has a:

a. lower moderating power and a lower absorption cross-section

b. higher moderating power and a lower absorption cross-section

c. lower moderating power and a higher absorption cross-section

d. higher moderating power and a higher absorption cross-section Answer: A.018 d.

Reference:

RSM 10-11 Question A.019 [1.0 point] (19.0)

Which ONE of the following atoms will cause a neutron to lose the most energy in an elastic collision?

a. U-238

b. Pb-208

c. C-12

d. H-1 Answer: A.019 d.

Reference:

Glasstone and Sesonske, Nuclear Reactor Engineering, Chapter 3, Section 3.77

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 8 of 29 Question A.020 [1.0 point] (20.0)

Based on the time versus exposure rate table below, which ONE of the following is the half life of an experimental sample irradiated in the core?

Time Exposure Rate 0 20 mR/hr 5 min 15.7 mR/hr 10 min 12.3 mR/hr 15 min 9.6 mR/hr 20 min 7.6 mR/hr

a. 11 min

b. 14 min

c. 17 min

d. 20 min Answer: A.020 b.

Reference:

Standard NRC Question DR = DR0 e t 12.3 = 20e *10

= 1 *

(

ln 12.3 )

20 = 0 .0486 min 1 10 ln 2 ln 2 t1 / 2 = = =14.258 min 0 .0486 min 1

B. Normal & Emerg Operating Procedures & Radiological Controls Page 9 of 29 Question B.001 [1 point] (1.0)

Select the MINIMUM amount of time that must be spent performing license activities in order to maintain your license active.

a. 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per month

b. 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per month

c. 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per quarter

d. 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per quarter Answer: B.001 c.

Reference:

10 CFR 55.53 Question B.002 [1 point] (2.0)

Which one of the followings describes requirements which must be observed when "locking out" facility equipment after permission is granted?

a. SRO witness lockout, SRO will verify safe system condition, Superintendent must be notified, the system must be tagged out, a notation as to the system being locked out shall be made on the status board.

b. SRO will witness lockout, RO will verify safe system condition, Superintendent must be notified, the system must be tagged out, a notation as to the system being locked out shall be made on the status board.

c. SRO will witness lockout, person performing the work will perform lockout, person performing the work will retain the key on their person, the system must be tagged out, a notation as to the system being locked out shall be made on the status board.

d. SRO will verify safe system condition, any member of the NRL/RRPO Staff will witness lockout, person performing the work will perform lockout, the person performing the work will retain the key on their person, the system must be tagged out.

Answer: B.002 c.

Reference:

PM 1.14.3

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 10 of 29 Question B.003 [1 point] (3.0)

Which ONE of the following describes the effect of a loss of electrical power to the Scam System?

a. Reactor protection from the automatic scrams are still in effect.

b. The reactor will experience a minor scram but no alarm functions or instrument indications are active.

c. Signal lights associated with the scrams are active but reactor protection from automatic scrams are lost.

d. The Scam System Power Failure alarm will actuate if all electrical power to the reactor building has occurred.

Answer: B.003 a.

Reference:

PM 5.7.1 Question B.004 [1 point] (4.0)

Which one of the following Film Badge colors identifies the wearer as someone who is permitted to escort members of the general public through the reactor building?

a. Blue

b. Red

c. Yellow

d. Green Answer: B.004 c.

Reference:

PM 1.12, p. 1 Question B.005 [1 point] (5.0)

Which of the following is not considered to cause a whole body exposure?

a. Ar-41

b. I-131

c. Xe-133

d. Kr-88 Answer: B.005 b.

Reference:

Glasstone/Sesonske - Chapter 9

B. Normal & Emerg Operating Procedures & Radiological Controls Page 11 of 29 Question B.006 [1 point] (6.0)

The fuel management pattern of the MITR-II usually calls for refueling (following operation at full power for a long period of time) when the shim bank position reaches 16 inches. Approximately what is the core excess reactivity at this time?

a. Approximately 200 mbeta of excess reactivity

b. Approximately 0.2 Beta of excess reactivity

c. Approximately 1 Beta of excess reactivity

d. Approximately 2 Beta of excess reactivity Answer: B.006 c.

Reference:

RSM 10.8 Question B.007 [1 point] (7.0)

The maximum reactivity worth of a single movable experiment allowed by Tech. Specs is:

a. 0.2 %Delta K/K

b. 0.5 %Delta K/K

c. 1.0 %Delta K/K

d. 1.8 %Delta K/K Answer: B.007 a.

Reference:

MIT TS 6.1.1 Question B.008 [1 point] (8.0)

Per Technical Specifications, who may authorize the use of a temporary change to a checklist provided it does not change the intent of the original approved procedure?

The Director of Reactor Operations.

a. The Director of Reactor Operations.

b. The SRO on duty and the Reactor Operator.

c. A licensed SRO and another member of the facility staff.

d. A licensed Reactor Operator and the Reactor Radiation Protection Officer.

Answer: B.008 c.

Reference:

T.S. 7.8.3

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 12 of 29 Question B.009 [1 point] (9.0)

The basis for the D2 concentration limit in the Helium gas cover blanket for the D2O reflector system is to:

a. minimize personnel radiation exposure.

b. limit the disassociation of D20 in the reflector.

c. minimize the contamination of the Helium cover gas.

d. prevent a flammable concentration of D2 gas in the Helium blanket.

Answer: B.009 d.

Reference:

TS 3.3 Question B.010 [1 point] (10.0)

A radiation survey performed 30 minutes after shutdown from a week of full power operation indicated 1500 mR/hr on contact with the main heat exchangers. Which of the following is true?

a. This reading is normal, most likely caused by N-16.

b. This reading is normal, most likely caused by Na-24.

c. This reading is abnormal, most likely caused by tritium.

d. This reading is abnormal, most likely caused by fission products.

Answer: B.010 d.

Reference:

AOP 5.0 Question B.011 [1 point] (11.0)

A 15 ml sample of primary water is removed from the sample station. What is the dominant nuclide you would expect assuming routine (normal) operation?

a. Na-24

b. U-235

c. Co-60

d. Ar Answer: B.011 a.

Reference:

RRPO surveys

B. Normal & Emerg Operating Procedures & Radiological Controls Page 13 of 29 Question B.012 [1 point] (12.0)

If the reactor core tank level can not be maintained at or above the low level scram (-4"), what class of emergency would be declared?

a. Unusual Event

b. Alert

c. Site Area

d. General Answer: B.012 a.

Reference:

PM 4.4.4.15 Question B.013 [1 point] (13.0)

Which one of the following most closely represent the exposure rate on top of the reactor (above the shielding) when the reactor is operating at 4.9 MW?

a. 1 mR/hr

b. 10 mR/hr

c. 20 mR/hr

d. 50 mR/hr Answer: B.013 b.

Reference:

RRPO surveys Question B.014 [1 point] (14.0)

Which ONE of the following is the assembly area in the event of a NW12 fire alarm?

a. Reception Area.

b. NW13 Machine Shop.

c. Far side of Albany Street.

d.Campus Police Headquarters.

Answer: B.014 c.

Reference:

PM 4.4.4.11 Appendix A

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 14 of 29 Question B.015 [1 point] (15.0)

What must be assumed if the high radiation set-up area vault alarm has actuated?

a

a. Inadvertent criticality has occurred.

b. Person went by with hot source.

c. Electrical short in instrument.

d. Vault monitor failed.

Answer: B.015 a.

Reference:

AOP 5.6.1 Question B.016 [1 point] (16.0)

During continuous power operation with the automatic control system it may be necessary for the operator to reshim the control blades to maintain the regulating rod within its useful range.

Which ONE of the following describes the requirements associated with this reshim of control blades?

a. The duty supervisor must approve all reshims prior to performance.

b. Reactor power is to be maintained within 2.5% of the desired level while reshimming.

c. The first motion of any control absorber during a reshim should be inward so as to lower reactor power.

d. All shim blades must be maintained within 2.5 inches of each other during the reshim and within 1.0 inch following the reshim.

Answer: B.016 c.

Reference:

PM 2.4, Step 3(a), p 3.

B. Normal & Emerg Operating Procedures & Radiological Controls Page 15 of 29 Question B.017 [1 point] (17.0)

Which one of following is the maximum reactor outlet temperature that will prevent exceeding the MITR-II safety limit?

Assume the following core conditions:

Reactor Power = 4.9 MW Primary Flow = 1960 gpm Core Tank level = 8 ft.

a. 82 ºC

b. 78 ºC

c. 73 ºC

d. 68 ºC Answer: B.017 b.

Reference:

T.S. 2.1 (Safety Limits); PM 5.1.3 (Follow-up Action Step 7)

Question B.018 [1 point] (18.0)

In the event of a large tritiated water spill, what type of action should be followed for operation of the ventilation system?

a. Close the dampers, thus securing the ventilation system.

b. Turn off the ventilation system until radiation levels decrease.

c. Continue to operate the ventilation system as normal, except do not blow air directly on the spill.

d. Turn up the trips on the gas and particulate monitors so that the dampers will not close unless done so manually.

Answer: B.018 c.

Reference:

MIT Comments to 1997 written examination.

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 16 of 29 Question B.019 [1 point] (19.0)

Which one of the following statements regarding reactor operations is TRUE?

a. Reactor operations may continue if a required member of the shift must leave for emergency personal problems. An adequate replacement shall be secured as soon as possible.

b. Work shall not be conducted in the reactor building unless a reactor supervisor or a reliable person appointed by a reactor supervisor is present at the facility.

c. If a reactor startup is scheduled for 3.00 PM, the morning surveillance checksheet shall be completed at least 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> prior to the startup.

d. The shift supervisor may grant permission to an experimenter to irradiate acids or other corrosive liquids.

Answer: B.019 b.

Reference:

MITR PM 1.14 Question B.020 [1 point] (20.0)

What are the four (4) variables that constitute the safety limit?

a. Excess reactivity of the control system; height of water above the outlet end of the heated section; total reactor thermal power; reactor coolant outlet temperature.

b. Reactor coolant total flow rate; radiation level above the core tank; reactor coolant outlet temperature; height of water above the outlet end of the heated section.

c. Total reactor thermal power; reactor coolant total flow rate; reactor coolant outlet temperature; height of water above the outlet end of the heated section.

d. Height of water above the outlet end of the heated section; total reactor thermal power; reflector tank D20 flow rate; reactor coolant total flow rate.

Answer: B.020 c.

Reference:

MITR-II TS 2.1

C. Facility and Radiation Monitoring Systems Page 17 of 29 Question C.001 [1.0 point] (1.0)

The spent fuel storage pool alarm will activate in response to:

a. spent fuel storage pool pump high discharge pressure.

b. a leak in the cleanup system.

c. high radiation in the pool.

d. high level in the pool.

Answer: C.001 b.

Reference:

PM 5.7.12 Question C.002 [1.0 point] (2.0)

The minimum complement of radiation monitors is:

a. one effluent (stack or plenum), one area monitor capable of warning personnel, one water monitor and one tritium sampler.

b. one plenum monitor capable of closing the dampers, one area monitor capable of warning personnel, one water monitor and one tritium sampler.

c. one plenum monitor capable of closing the dampers, one area monitor capable of warning personnel, one water monitor and one tritium sampler.

d. one plenum monitor capable of closing the dampers, one stack monitor, one area monitor capable of warning personnel, one water monitor and one tritium sampler.

Answer: C.002 d.

Reference:

Tech. Spec. 3.8.2 Question C.003 [1.0 point] (3.0)

Which ONE of the following alarm conditions will result in an automatic scram?

a. High Temperature Reflector Outlet.

b. Low Voltage Chamber Power Supply

c. High Level Emergency Power Channel.

d. Low Level Shield Coolant Storage Tank.

Answer: C.003 b.

Reference:

RSM-9.3 to 9.5

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 18 of 29 Question C.004 [1.0 point] (4.0)

MP-6 and MP-6A measure inlet pressure to the reactor core. What flowrate corresponds to a minimum flow rate required by the technical specifications?

a. 1000 gpm

b. 1500 gpm

c. 1800 gpm

d. 2000 gpm Answer: C.004 c.

Reference:

PM 5.2.10 Question C.005 [1.0 point] (5.0)

Which ONE of the following describes the purpose for the subcritical interlock?

a. To prevent withdrawing more than one shim blade at a time.

b. To allow for performance of individual shim blade drop time testing.

c. To ensure the nuclear instruments are on scale prior to allowing shim blade withdrawal.

d. To aid in maintaining the shim blade bank at a uniform height during the final approach to criticality.

Answer: C.005 d.

Reference:

RSM-4.3 Question C.006 [1.0 point] (6.0)

Which ONE of the following describes an automatic response of the ventilation system?

a. If temperature of the outside air drops below freezing the intake fan will trip.

b. If the main intake damper fails to close within ten seconds of a trip signal, then the intake fan will trip.

c. If the auxiliary intake damper fails to close within ten seconds of a trip signal, then the main damper will close.

d. In the "weekend-open" position, if activity is detected by the plenum monitors, the inlet dampers and intake fan will trip.

Answer: C.006 d. a. Answer changed per facility comment.

Reference:

RSM-8.12

C. Facility and Radiation Monitoring Systems Page 19 of 29 Question C.007 [1.0 point] (7.0)

If the radiation monitor in the off-gas system detects abnormal radiation levels, the pool ventilation will be automatically secured. Protection from overpressure of the coolant system in this condition is provided by:

a. a Blowout patch on the coolant storage tank.

b. a Vacuum breaker on suction side of the off-gas blower.

c. the sample line connections between the isolation valves.

d. a relief valve on the off-gas discharge piping which relieves to the main ventilation exhaust plenum.

Answer: C.007 a.

Reference:

RSM-3.4, Section 3.2.5 Question C.008 [1.0 point] (8.0)

Which one of the following is the alarm setting on the core outlet temperature recorder?

a. 50 ºC

b. 53 ºC

c. 55 ºC

d. 60 ºC Answer: C.008 b.

Reference:

PM 5.2.6 Question C.009 [1.0 point] (9.0)

During refueling of the core the indicated neutron level has increased by a factor of 2.5. Which one of the following operator actions is required to be taken?

a. Evacuate personnel from the reactor top.

b. Dump the reflector, if not already dumped.

c. Notify Radiation Protection to perform a radiation survey of the reactor top area.

d. Notify personnel on the reactor top to insert a dummy element in place of the fuel element just removed.

Answer: C.009 b.

Reference:

PM 3.3.1.1, Step 39, p 3.

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 20 of 29 Question C.010 [2.0 point, 0.25points each] (11.0)

Match the facility conditions in Column I with the type of response expected to occur from the Reactor Safety System in Column II. (Assume the reactor is critical.) Items in Column I have only one correct answer and items in Column II may be used once, more than once or not at all.

Column I (Condition) Column II (Response)

a. Core tank level 2 inches 1. Alarm ONLY.

below overflow pipe.

2. Rod withdrawal inhibited.

b. Shield coolant flow equals 55 gpm. 3. Scram.

c. Reactor outlet temperature 4. No safety system response equals 50 ºC.

d. Reactor building vacuum equals 1.2 inches water above atmospheric.

e. Primary cleanup system temperature equals 52 ºC.

f. D2O flow equals 88 gpm.

g. Core Purge flow equals 2.0 cfm

h. Secondary Water Monitor sample flow equals 1 gpm Answer: C.010 a. = 1. 2; b. = 3; c. = 4; d. = 1. 2; e. = 1; f. = 3; g. = 1;

h. = 1 Answer key changed per facility comment.

Reference:

MIT RSM 9.9 & RSM 7.10 (7.5)

Question C.011 [1.0 point] (12.0)

Why is blowdown of the cooling tower basins required to be secured whenever the reactor is shutdown?

a. Shutdown cooling system efficiency may be adversely affected due to blowdown.

b. The secondary water monitors cannot detect leakage when the reactor is shutdown due to short-lived isotopes.

c. The cooling tower level detectors and automatic makeup system is not energized when the reactor is shutdown.

d. Secondary system level cannot be adequately measured when shutdown due to thermal expansion during operation.

Answer: C.011 b.

Reference:

RSM 7.4.1

C. Facility and Radiation Monitoring Systems Page 21 of 29 Question C.012 [1.0 point] (13.0)

The reactor is operating at 4.9 MW with an experiment loaded in the pneumatic system.

How long after receiving a "Vacuum Off Pneumatic System" alarm will the temperature in the pneumatic tubes reach 100 ºC?

a. 30 seconds

b. 6 minutes

c. 45 minutes

d. 120 minutes Answer: C.012 b.

Reference:

PM 5.5.1 Question C.013 [1.0 point] (14.0)

What automatic action occurs when a high radiation alarm is received on the Sewer Monitor? Assume that the Sewer Monitor is in its normal mode of monitoring liquid radioactive waste being pumped from the sumps to the waste tanks.

a. The Radioactive Liquid Waste System Containment Isolation valve closes.

b. The Inlet City Water Solenoid valve closes.

c. The on-line Sewer pump trips.

d. The Sump pumps trip.

Answer: C.013 d.

Reference:

RSM 7.7 and 8.24 Question C.014 [1.0 point] (15.0)

Rod withdrawal times are measured at least annually. The blade system must be adjusted if the time to withdraw a blade a distance of 8.5 inches is measured to be other than:

a. 7 minutes +/- 1%

b. 5 minutes +/- 10%

c. 2 minutes +/- 10%

d. 1 minutes +/- 10%

Answer: C.014 c.

Reference:

MIT Question Bank Sect. B pg. 6 of 13

A. Reactor Theory, Thermodynamics and Facility Operating Characteristics Page 22 of 29 Question C.015 [1.0 point] (16.0)

Which one of the following sensors uses a flow nozzle?

a. Shield flow PF-1.

b. Primary flow MF-1

c. Reflector flow DF-1

d. Secondary flow HF-1A Answer: C.015 b.

Reference:

RSM 6.4.1 & 6.4.2 Question C.016 [1.0 point] (17.0)

Which one of the following gives the reason for the stepped design of the beam port sleeve and plug?

a. Precludes radiation streaming.

b. Facilitates ease of insertion and removal.

c. Prevents D2O leakage if a break were to occur.

d. Maintains a negative pressure to inhibit activated air from leaking.

Answer: C.016 a.

Reference:

RSM 2-6 Question C.017 [1.0 point] (18.0)

If an Area Monitor detector is saturated, the Detector Signal Conditioner LED will read

a. All nines (9)

b. All zeros (0)

c. All dashes (-)

d. A blank screen Answer: C.017 c.

Reference:

RSM 7-2

C. Facility and Radiation Monitoring Systems Page 23 of 29 Question C.018 [1.0 point] (19.0)

Where are the plenum particulate monitors located in the ventilation system?

a. After the stack exhaust fan

b. Before the main exhaust damper

c. In between the exhaust filtering unit and the stack exhaust fan

d. In between the main exhaust damper and the exhaust filtering unit Answer: C.018 b.

Reference:

RSM 8-14 Question C.019 [1.0 point] (20.0)

Why is Helium used to blanket the D2O reflector system?

a. To prevent corrosion caused by nitrous oxide formation in air

b. To cool the empty spaces in the reflector above the D2O level

c. To keep the D2 and O2 from being released into the atmosphere

d. To prevent activation of the Oxygen in CO2 if CO2 were used instead Answer: C.019 a

Reference:

RSM 3-19