ML071230476

Retake Examination Report No. 50-134/OL-07-01, Worcester Polytechnic Institute

ML071230476
Person / Time
Site:	05000134
Issue date:	05/10/2007
From:	Johnny Eads NRC/NRR/ADRA/DPR/PRTB
To:	Laflamme S Worcester Polytechnic Institute
Eads J, NRR/ADRA/DPR/PRTB, 415-1471
Shared Package
ML070160003	List: ML070160004 ML071230476
References
50-134/07-001 50-134/07-001
Download: ML071230476 (11)

Text

May 10, 2007 Mr. Stephen J. LaFlamme, Reactor Supervisor Nuclear Reactor Facility Worcester Polytechnic Institute Worcester, MA 01609

SUBJECT:

RETAKE EXAMINATION REPORT NO. 50-134/OL-07-01, WORCESTER POLYTECHNIC INSTITUTE

Dear Mr. LaFlamme:

On April 11, 2007, you administered an NRC prepared operator licensing written examination at your Worcester Polytechnic Institute Reactor. The examination was conducted according to NUREG-1478, "Non-Power Reactor Operator Licensing Examiner Standards," Revision 1.

In accordance with 10 CFR 2.390 of the Commission's regulations, 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 document system (ADAMS). ADAMS is accessible from the NRC Web site at (the Public Electronic Reading Room) http://www.nrc.gov/NRC/ADAMS/indesx.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 Paul V. Doyle Jr. at (301)415-1058 or via internet E-mail at pvd@nrc.gov.

Sincerely,

/RA MM Mendonca for/

Johnny Eads, Chief Research and Test Reactors Branch B Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Docket No. 50-134

Enclosures:

1. Retake Examination Report No. 50-134/OL-07-01

2. Examination and answer key with facility comments included cc w/encls:

Please see next page

May 10, 2007 Mr. Stephen J. LaFlamme, Reactor Supervisor Nuclear Reactor Facility Worcester Polytechnic Institute Worcester, MA 01609

SUBJECT:

RETAKE EXAMINATION REPORT NO. 50-134/OL-07-01, WORCESTER POLYTECHNIC INSTITUTE

Dear Mr. LaFlamme:

On April 11, 2007, you administered an NRC prepared operator licensing written examination at your Worcester Polytechnic Institute Reactor. The examination was conducted according to NUREG-1478, "Non-Power Reactor Operator Licensing Examiner Standards," Revision 1.

In accordance with 10 CFR 2.390 of the Commission's regulations, 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 document system (ADAMS). ADAMS is accessible from the NRC Web site at (the Public Electronic Reading Room) http://www.nrc.gov/NRC/ADAMS/indesx.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 Paul V. Doyle Jr. at (301)415-1058 or via internet E-mail at pvd@nrc.gov.

Sincerely,

/RA MM Mendonca for/

Johnny Eads, Chief Research and Test Reactors Branch B Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Docket No. 50-134

Enclosures:

1. Retake Examination Report No. 50-134/OL-07-01

2. Examination and answer key with facility comments included cc w/encls:

Please see next page DISTRIBUTION w/ encls.:

PUBLIC RNRP R&TR r/f JEads Facility File (EBarnhill) O-6 F-2 MMendonca ADAMS ACCESSION #: ML071230476 TEMPLATE #:NRR-074 OFFICE PRTB:CE IOLB:LA E PRTB:BC NAME PDoyle EBarnhill Jeads:MMendonca for DATE 05/04/2007 05/08/2007 05/10/2007 C = COVER E = COVER & ENCLOSURE N = NO COPY OFFICIAL RECORD COPY

Worcester Polytechnic Institute Docket No. 50-134 cc:

City Manager City Hall 455 Main Street, Room 309 Worcester, MA 01608 Office of the Attorney General Environmental Protection Division 19th Floor One Ashburton Place Boston, MA 02180 Director Radiation Control Program Department of Public Health 90 Washington Street Dorchester, MA 02121 Nuclear Preparedness Manager Massachusetts Emergency Management Agency 40 Worcester Road Framingham, MA 01702-5399 Department of Environmental Protection One Winter Street Boston, MA 02180 Carol Simpson, Ph. D.

Provost and Senior Vice President Provost's Office Worcester Polytechnic Institute 100 Institute Road Worcester, MA 01609-2280 Gretar Tryggvason, Professor and Head Department of Mechanical Engineering Worcester Polytechnic Institute 100 Institute Road Worcester, MA 01609-2280 Test, Research, and Training Reactor Newsletter University of Florida 202 Nuclear Sciences Center Gainesville, FL 32611

U. S. NUCLEAR REGULATORY COMMISSION OPERATOR LICENSING RETAKE EXAMINATION REPORT REPORT NO.: 50-134/OL-07-01 FACILITY DOCKET NO.: 50-134 FACILITY LICENSE NO.: R-61 FACILITY: Worcester Polytechnic Institute EXAMINATION DATES: April 11, 2007 SUBMITTED BY: ___________/RA/____________________ May 2, 2007 Paul V. Doyle Jr., Chief Examiner Date

SUMMARY

The NRC prepared a retake examination (Section A only) which was mailed to the facility for administration. The facility administered the examination and returned the candidate's answer sheets for grading. The candidate passed the written examination.

REPORT DETAILS

1. Examiners:

Paul V. Doyle Jr., Chief Examiner

2. Results:

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

3. Exit Meeting:

Paul V. Doyle Jr., Examiner, U.S. Nuclear Regulatory Commission Stephen J. Laflamme, Reactor Supervisor, Worcester Polytechnic Institute The examiner and the reactor supervisor conducted an exit meeting per telephone call on April 11, 2007. The facility identified one question (A.08) which was missing the associated figure.

The examiner decided to delete this one question. The facility also identified A.11 as a question with two correct answers, either d or b. The answer key has been modified to show two correct answers b and d. The facility had no other comments. Question A.11 will be modified to replace the current distractor b with one which is incorrect.

ENCLOSURE 1

OPERATOR LICENSING EXAMINATION With Answer Key WORCESTER POLYTECHNIC INSTITUTE January 22, 2007 ENCLOSURE 2

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 2 Question A.01 [1.0 point]

The number of neutrons passing through a square centimeter per second is the definition of which ONE of the following?

a. Neutron Population (np)

b. Neutron Impact Potential (nip)

c. Neutron Flux (nv)

d. Neutron Density (nd)

Question A.02 [1.0 point]

The Fast Fission Factor () is defined as The ratio of the number of neutrons produced by

a. fast fission to the number produced by thermal fission.

b. thermal fission to the number produced by fast fission.

c. fast and thermal fission to the number produced by thermal fission.

d. fast fission to the number produced by fast and thermal fission.

Question A.03 [1.0 point]

During a fuel loading of the core, as the reactor approaches criticality, the value of 1/M:

a. Increases toward one

b. Decreases toward one

c. Increases toward infinity

d. Decreases toward zero Question A.04 [2.0 points, 0.4 each]

Given a mother isotope of (35Br87)*, identify each of the daughter isotopes as a result of , +, -, , or n, decay.

a. 33 As83

b. 34 Se87

c. 35 Br86

d. 35 Br87

e. 36 Kr87

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 3 Question A.05 [1.0 point]

Which ONE of the following is the definition of the term Cross-Section?

a. The probability that a neutron will be captured by a nucleus.

b. The most likely energy at which a charge particle will be captured.

c. The length a charged particle travels past the nucleus before being captured.

d. The area of the nucleus including the electron cloud.

Question A.6 [1.0 point]

Given the data in the table to the right, which ONE of the following is the closest to the half-life of the material?

TIME ACTIVITY

a. 11 minutes 0 minutes 2400 cps

b. 22 minutes 10 minutes 1757 cps 20 minutes 1286 cps

c. 44 minutes 30 minutes 941 cps

d. 51 minutes 60 minutes 369 cps Question A.07 [1.0 point]

When performing rod calibrations, many facilities pull the rod out a given increment, then measure the time for reactor power to double (doubling time), then calculate the reactor period. If the doubling time is 42 seconds, what is the reactor period?

a. 29 sec

b. 42 sec

c. 61 sec

d. 84 sec Question A.08 [1.0 point] Question deleted per facility comment Using the graphs provided in the handout. Choose the ONE which most closely depicts the reactivity versus time plot for xenon for the following evolution. Bring the reactor to 100% power (clean core) and operate for four days (96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />). Shutdown the reactor for 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br />. Bring the reactor to 50% power for a day (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />).

a. A

b. B

c. C

d. D

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 4 Question A.09 [1.0 point]

Which ONE of the following will cause the reactor to reach criticality at a higher rod height?

a. Increase in moderator temperature

b. Increase in barometric pressure

c. adding new fuel

d. inserting a positive reactivity experiment Question A.10 [1.0 point]

Keff is K4 times

a. the fast fission factor ()

b. the total non-leakage probability (f x th)

c. the reproduction factor ()

d. the resonance escape probability (p)

Question A.11 [1.0 points]

Which ONE of the following causes indicated power (Startup Channel Count Rate) to stabilize several hours after a reactor trip? Assume reactor was operated for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> at 100 Kwatts, and no core alterations or changes in experiments.

a. Decay of compensating voltage at low power levels.

b. Actual power dropping below noise level for the instrumentation.

c. Decay of the longest lived delayed neutron precursor.

d. Subcritical multiplication of Source neutrons within the reactor.

Question A.12 [1.0 point]

You enter the control room and note that all nuclear instrumentation show a steady neutron level, and no rods are in motion. Which ONE of the following conditions CANNOT be true?

a. The reactor is critical.

b. The reactor is subcritical.

c. The reactor is supercritical.

d. The neutron source has been removed from the core.

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 5 Question A.13 [2.0 points, 1/2 each]

Match each term in column A with the correct definition in column B.

Column A Column B

a. Prompt Neutron 1. A neutron in equilibrium with its surroundings.

b. Fast Neutron 2. A neutron born directly from fission.

c. Thermal Neutron 3. A neutron born due to decay of a fission product.

d. Delayed Neutron 4. A neutron at an energy level greater than its surroundings.

Question A.14 [1.0 point]

Shown below is a trace of reactor period as a function of time.

Between points A and B reactor power is:

a. continually increasing.

b. continually decreasing.

c. increasing, then decreasing.

d. constant.

Question A.15 [1.0 point]

The reactor supervisor tells you that the Keff for the reactor is 0.955. How much reactivity must you add to the reactor to reach criticality?

a. +0.0471

b. +0.0450

c. -0.0471

d. -0.0450

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 6 Question A.16 [1.0 point]

By definition, an exactly critical reactor can be made prompt critical by adding positive reactivity equal to

a. the shutdown margin

b. the Kexcess margin

c. the eff value

d. 1.0 %K/K.

Question A.17 [2.0 points, 1/2 each]

Using the drawing of the Integral Rod Worth Curve provided, identify each of the following reactivity worths.

a. Total Rod Worth 1. B - A

b. Actual Shutdown Margin 2. C - A

c. Technical Specification Shutdown Margin Limit 3. C - B

d. Excess Reactivity 4. D - C

5. E - C

6. E - D

7. E - A

Section A: L Theory, Thermodynamics & Facility Operating Characteristics Page 7 A.01 c REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.02 c REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.03 d REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.04 a, ; b, +; c, n; d, ; e, -

REF: STD NRC question.

A.05 a REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.06 b REF:

A.07 c REF: ln (2) = -time/ = time/(ln(2)) = 60.59 . 61 seconds A.08 Question deleted per facility comment REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.09 a REF: Burn, Reed Robert, Introduction to Nuclear Reactor Operations, © December 1988, § A.10 b REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.11 d or b 2nd correct answer added per facility comment.

REF: Burn, Reed Robert, Introduction to Nuclear Reactor Operations, © December, 1988, § 5.2.1 - 5.3 pp. 5 5-13.

A.12 c REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.13 a, 2; b, 4; c, 1; d, 3 REF: Burn, Reed Robert, Introduction to Nuclear Reactor Operations, © December, 1988, § A.14 a REF: Introduction to Nuclear Reactor Operations, ©1982, Reed Robert Burn § A.15 a REF: = (Keff1 - Keff2) ÷ (Keff1

• Keff2) = (0.9550 - 1.0000) ÷ (0.9550

• 1.0000)

= -0.0450 ÷ 0.9550 = -0.0471 A.16 c REF: Burn, R., Introduction to Nuclear Reactor Operations, © 1988, § A.17 a, 7; b, 2; c, 1; d, 5 REF: