ML20134D367

Exam Rept 50-151/OL-85-01 on 850724-25.Exam Results:One Senior Reactor Operator Passed Written & Operational Exam

ML20134D367
Person / Time
Site:	University of Illinois
Issue date:	07/30/1985
From:	Ferrell R, Mcmillen J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20134D333	List: ML20134D329 ML20134D367
References
50-151-OL-85-01, 50-151-OL-85-1, NUDOCS 8508190195
Download: ML20134D367 (28)

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h' U.S. NUCLEAR REGULATORY COMMISSION REGION III Report No. 50-151/0L-85-01 Docket No. 50-151 Licensee: University of Illinois 214 NEL 103 S. Goodwin Urbana, IL 61801 Facility Name: University of Illinois Examination Administered At: TRIGA Facility Examination Conducted: 1 SR k.

Examiner: R. R. Ferrell July 30, 1985 Date l

Approved By: . I. McMillen July 30, 1985 Operating License Section Date Examination Summary _

Examination Administered on July 24-25, 1985 (Report No. 50-151/0L-85-01)

Results: 1 SRO passed the written and. operational exam.

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-O REPORT DETAILS

1. Examiner R. R. Ferrell, Chief Examiner

2. Examination Review Meeting At the conclusion of the written examination, the examiner met with Gerald Beck and Craig Pohlod of the Reactor Staff to review the written examination. A list of comments was generated and, along with the examiners responses, is included as a separate attachment.

3. Exit Meeting At the conclusion of.the site visit, the examiner met with members of the reactor staff to discuss results of the examination. They were informed that the one (1) SRO candidate clearly passed the operational portion of the examination.

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7 UNIVERSITY OF ILLIN0IS EXAM COMMENTS General The time allotted for a thorough review was inadequate and hence some of the comments may not have the clarity that is desired. The following comes from notes that were taken during the review. Only those questions where some concern was noted are included.

Examiner Response The two hour time. limit for the review was in accordance with the Operator Licensing Standard. This policy has been changed and as of August 1, 1985, the facility will be given a copy of the exam to keep following it's administration. A list of comments will be generated and given to the examiner by the end of the site visit.

Comment H.1(b)

It was not clear what the question wants. After looking at the expected answer, I was even more confused. Any concepts from same had never previously been seen.

Apparently the only source for the question a was previous exam as the relationships do not appear in any textbook.

Examiner Response H.1(b)

Agreed. This questiou was deleted from the exan as it required the applicant to provide an answer derived frem information not provided in the question.

Comment H.1(d)

The answer was basically correct, although some delayed neutrons can have sufficient energy to cause a fast fission with U-238.

Examiner Response H.1(d)

Agreed. The above comment was added to the answer key.

Comment H.2 Buckling is not covered in our operational lectures. To me, it is only of interest to recctor design rather than operation.

Examiner Response H.2 Disagree. Buckling is a concept the operator should be aware of for a good

' understanding of overall reactor operation. As buckling affects many plant L parameters, as well as other parameters affecting it, the operator should have a brief knowledge of it. The candidate did well on the question.

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F Comment H.S If a system is just " prompt critical" some of the short half-life delayed neutrons will be involved in determining the period. The expected answer occurs when a system is above " prompt critical."

• Examiner Response H.S Agreed. The above comment was added to the answer key and question graded accordingly.

Comment H.7 NE 390 notes will include the fact that the control rods will absorb more neutrons. The cell effect considers only the fuel and moderator although both of these cause thermal utilization to decrease.

Examiner Response H.7 Agreed. The above comment was added to the answer key.

Comment H.8(b)

Because of 20% enrichment, the thermal lifetime is shorter since there are more U235 atoms to absorb neutrons. We use 45 microseconds for calculations.

Examiner Response H.8(b)

Agreed. The above comment was added to the answer key.

Comment-H.8(c)

Expected answer is certainly correct, but could have other correct answers.

Examiner Responso H.8(c)

Disagree. The answer provided is correct and the question solicits the response provided.

Section I:

Comment I.1(c)

Changed to present CAM in use. Normally set at 5,000 cpm.

Examiner Response I.1(c)

Agreed. This was pointed out by candidate during the exam and the question changed to the CAM Unit setpoint.

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Comment I.3 Question was changed since it was not applicable.

' Examiner Response I.3 s Agreed. The question was changed during the exam to explain the operation of the CAM Unit and the answer key changed to the correct answer.

Comment I.5(b)

Answer was in expected answer for part (a).

Examiner Response I.5 Agreed. The answer key was corrected.

Comment I.6(b)

Was not sure of source for the first expected answer. For visitors, our rule is one dosimeter for 10 individuals.

Examiner Response I.6(b)~

- The source of the question was the FSAR. The second comment is already in the answer key.

Comment I.8 The exhaust system was designed to remove particulates and get better dilution before reaching occupied areas. It does give values for the release of A-41, but the purpose isn't for this removal .

Examiner Response 1.8 The examiner agrees the question could have been worded better, but is still applicable since it was taken from the system description provided. The candidate did well on the question.

Comment I.9 You may not get specific items in the expected answer. Basically any water on

. the lower level does go to the retention tank.

Examiner Response I.9 The system description listed specific sources of the water going to the retention tank, and since there is only a limited number of systems associated with the TRIGA, the candidate should know them.

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Comment I.10 The question is worded incorrectly to get expected answer. The answers to the question are in 10 CFR 20 but you may get an emergency case answer of 25 rem.

Examiner Response I.10 Agreed. This question was graded very liberally based on the above comment.

Comment J.1 Hight get variety of answers - do not remember question or expected answer.

However, I do not believe this came from 390R notes.

Examiner Response J.1 The examiner does not understand the above comment but a review of the question and answer was performed and the question is basic theory the candidate should understand.

Comment J.2 This was true when we first did pulsed operation. At the present time, the gap stays about the same and no change in reactivity or fuel temperatures have been noted for the past 10 years.

Examiner Response J.2 Disagree. Although the above may be true, the answer in the key was from material provided to prepare the exam. The question and answer could be true and therefore is relevant. The candidate did well on the question.

Comment J.6 Question does not ask for reasons although these are given in the expected answer. Also No. (1) is not involved in the question.

Examiner Response J.7 Agreed. All the information provided in the answer is not necessary for full credit. It is only for use by the examiner and candidates answer was graded accordingly.

Comment J.8 Changed to Linear Recorder since no answer for % Power.

Examiner Response J.8 Agreed. The question was clarified during the administration of the exam, a

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o Comment J.9 May get actual levels where scrams occur - 16" and 20" rather than distance to core. Normal distance to core is 16 feet.

Examiner Response J.9 Agreed. Additional Responses were added to the answer key.

Section K:

Comment K.6 Refer to amendment for present measurements. Item (b) in expected answer is not a surveillance requirement.

Examiner Response K.6 Agreed. The candidates response was graded according to the above comment.

Comment K.7 Actual enrichment is 8.5% and ratio is 1:1.7.

Examiner Response K.7

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Agreed. The answer key was changed to incorporate the above comment'.

Section L ' o Comment L.1(d)

Ramp rod has not been used since 1965.

Examiner Response L.1(d)

Agreed. This question was deleted from the exam.

Comment L.2 May get operating requirements instead of Technical Specification answers.

These are to check the nv and temp., measure the rod worth; 15 watt rod positions for cold critical; and fuel temperature checks from 50-250 KW.

Examiner Response L.2 Disagree. Although the above comment is true, the question asked specifically for the Technical Specification requirements.

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Comment-L.3 Not in Technical Specifications - Without test and answers, I am not sure what this means.

. Examiner Response L.3 ,

l Disagree. This'is from the Technical Specifications definitions section.

Comment L.4 (d)

Actual value is 1.KW.

Examiner Response L.4

.6 Agreed. The answer key was corrected.

Comment L.9 Should be-10'KW and 10 MW. .

Examiner Response L.9 Agreed. The. additional numbers were added to the key and either answer will be acceptable.

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. vCG U.S. NUCLEAR REGULATORY C0tWISSION SENIOR REACTOR OPERATOR LICENSE EXAMINATION C. PDHLCD

ACILITY

University of Illinois REACTOR TYPE: TRIGA DATE ADMINISTERED: July 24, 1985 EXAMINER: R. R. Ferreli APPLICANT:

INSTRUCTIONS TO APPLICANT:

Use separate paper for tne answers. Write answers on one siae only. Staple ouestion sheet on top of the answer sneets. Points for eacn question are indicated in parentheses after the question. Tne passing grade requires at least 70%.in eacn category ano a final grace of at least 70%.

% of Category  % Of Applicant's Category Value Tota' Score Value Category 20 20 H. Reactor Theory 20 20 1. Radioactive Material Handling, Disposal anc Hazaras 20 20 J. Soecific Ocerating Characteristics 20 20 K. Fuel Manaling and Core Parameters 20 20 L. Administrative Procedures, Concitions, and Limitations 100 100 TOTALS Final Graae  %

All work done on this exam is my own. I nave neither given nor received aid.

Applicant's Signature i

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a H. REACTOR THEORY H.1 The delayed neutron fractions for U-235 and U-238 are .0065 and

.0157 respectively.

a. How does the magnitude of your core 5 delayed neutron 1.0 fraction compare to those stated for U-235 and U-238? ( . 75 ', gg

t. Ex= est the ateve velues 4 a ' ter-c c' de'te-" pe # #e- u$

yeu cc e- v4 ( . 75 ) at

c. How can sucn a small fraction of neutrons De of any 1.o significance in your core? 1.7;)

of d Why don't delayed neutrons cause fission in U-238? 7f$ *E H.2 How is 82 (Buckling) related to driving a control rod into tne

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core? (1.75)

H.3 With tne TRIGA critical and an external source present, the power level would be increasing at a linear rate (tne rate of increase depends on source strength). If the source is removed the power level would decrease. Explain. (1.75)

H.4 Define the following terms.

a. Period (1.0)

b. Poison (1.0)

c. Xenon Oscillation (1.0)

H.5 Describe wnat effects have and are taking place if a reactor is

" prompt critical." (2.0)

H.6 Will the following items add or subtract reactivity when they

.are added to the reactor core?

a. Fuel Elements (1.0)

b. Moderator (1.0)

c. Control Rods (1.0)

H.7 The TRIGA has a prompt negative temperature coefficient composed of several effects. Discuss these effects. (Tnree reauired for full credit.) (2.50)

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4 H.8 a. What'.is meant by neutron lifetime? -(1.0)

.D. How is neutron lifetime related to the composition of the reactor fuel? (1.0)

c. How does the neutron lifetime l relate to the~ pulsing -

cacaoility of the TRIGA?' (1.0)

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4 I. RADI0 ACTIVE MATERIAL HANDLING. DISPOSAL, AND HAZARDS I .1 List the following normai alarm settings on radiation monitors.

a. Reactor top (.75) -

c. Demineralizer (.75)

C. A M (. po R r a t3tg

c. Reactor i::/:: Ming (.75)

d. Lobby (.75)

I.2 What radiation levels would you expect to finc in areas marked as follows?

a. Caution, Radiation Area (1.0)

b. Caution, Hign Radiation Area (1.0)

I.3 The air particulate monitor is utilized for raoiation detection at your reactor.

a. List tne Awd' alarm condition settinas for the monitor.

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(1.0)

b. How are each of these alarm conditions indicated to the operator? (2.0)

MOTE: G0Bvc0To BE AALED To CAM Onit otoMUSA I.4- What is the first isotope likely to be seen in case of a fuel element rupture? (1.0)

I.5 Define the following terms.

a. Byproduct material (1.0)

o. Rem (1.0)

c. Rao (1.0)

I.6 a. What personnel monitoring devices shall be worn by reactor staff members? (1.0)

b. How does this differ from the requirements for visitors? (1.0)

I. 7 What two people (by job title) can authorize access to the reactor area for a visitor? (1.0)

I.8 What' radioactive gas is the building exhaust system designed to remove? (1.0)

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- I.'9 What-four sources crain' liquids into the 500 gallon. retention tank locatea unoer.the main floor of -the lab? (2.5)

. I.10 Under wnat conditions -specified in 10 CFR 20 can a licensee -

permit an individual into a restrictea area to recei/e a total occupational aose..to the wnole boay greater than specified? (1.5) -

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J. SPECIFIC OPERATING CHARACTERISTICS J.1 During the course of cerforming an experiment, the reactor is taken critical and levelea out at SKw, with a moderator temperature of 80 F_ Tne reactor is then snutoown, the moderator neated to 140 F tnrougn application of external heat. Another startup is made, and the operator levels off once more at the same indicated levels on his instruments, as were coserved in tne original run. Is the actuai reactor power now the same, nigner or lower tnan wnen it was at 80'F ? Explain your answer. (2.0)

J.2 One cnaracteristic of tne fuel elements usec in the Illinois aavanced TRIGA is that the fuel temperature and loss of reactivity for a given steaoy-state power level show an increase after they nave oeen pulsec a numoer of_ times. To wnat do you attribute .

this? (2.0)

J.3 How does the mode of forced cooling differ, in respect to achievable power levels, from natural convection anc wny? (1.5)

J.4 Assume the TRIGA reactor is operating at steaay state rated power anc is in auto controi. What control rod response would occur and wny for each of the following separately occurring events?

a. Gas emitted from an experiment bubbles up through the core. (1.0)

c. An extraneous neutron source was inadvertently brought within a distance of two feet from the core. (1.0)

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J. 5 Why co some nuclear instrumentation cnannels use a compensatea ionization chamber? Sketch a compensated ionization enameer and aescribe its tneory of operation. (3.0)

J.6 List 5 interlocks and their purpose that are incorporated into the control system to prevent overlapping operations between two modes. (4.0)

J.7 Control rod drive motors are AC powerec. Normally when power is removed from a motor, it will keeD rotating for a few moments.

How is this feature eliminated in the TRIGA rod drive? (1.5) adal J.8 When the % Power switch is placed in the calibrate position, the meter should reac: (A) 100% (B)'110% (C) 10% (D) the reading would depend on the setting of the potentiometer below the switch. (1.0)

J.9 List two (2) scrams associated with reactor water tank temperature and level. (1.5)

J.10 Describe how the operation of the flapper valves is checked for proper operation. (List the a steps used for full credit.) (1.5) 6 I l

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t K. FUEL HANDLING AND CORE PARAMETERS K.1 The following data were taken during tne loading of a reactor core:

No. of Elements Count Rate (CPS. rods out) 0 12 4 13 8 14 10 15 12 20 13 30 14 60

a. Estimate the number of fuel elements for criticality.

(Use attacned sneet of graph paper.) (1.5) . _ ,

b. Calculate the K of the reactor after loading the 13th element. (1.0)

. Does the shape of the reciDroCal multiplication Diot obtained for the loading indicate the source is too close.

too far away, or at an optimum distance witn respect to

-the detector. Exolain your answer. (1.0)

K.2 What advantages, if any, are gained by adding a fuel moderator section below the poison section of a control rod? (1.5)

K. 3 The manually driven rods and the transient rods (fast and adjustable) at the TRIGA contain both a poison section and a follower section.

a. Describe the comoosition of the rods including the follower and poison sections. (1.5)

b. What is the purpose of the follower section? (1.5)

K. 4 The reactor is in auto control wnen the log N power indicator starts to increase while the linear power indicator starts to decrease.

What is the most likely cause of this condition? (2.0)

K. 5 How is a sourceless startup prevented on your reactor? (2.0)

K. 6 What are the surveillance reouirements for the fuel elements for the TRIGA reactor? (4.0)

K. 7 Describe the following.

a. Standard Fuel Element (2.0)

D. Low Hydride Fuel Element (2.0)

r L. ADMINISTRATIVE PROCEDURES, CONDITIONS AND LIMITATIONS L.1 Concerning the Tecn Spec limiting conditions for coeration for (0.5 eacn) reactivity, fill in the blanks.

The reactor shall not be operated unless the following conditions exist.

a. The excess reactivity is less than

b. Any experiment with a reactivity worth greater than is securely fastened so as to prevent unplanneo removal from or insertion into the reactor.

c. The total of the absolute values of the reactivity worth of " '

all experiments in the ' reactor is less than O.  ? rc Or c;cillating red cannot bc added at rate exceeding-85 eer seennd.d6

e. The total reactivity worth of the two transient control rods is less than .

f. The drop time of a standard control rod from the fully withdrawn position to 90 percent of full reactivity insertion is less than .

g. The neutron count rate on the startuo channel is greater than L. 2 The Technical _ Specification lists two requirements that shall be followed in order to operate the reactor in the pulse mooe. What are these requirements? (Do not use those listeo in Question L.l.)  !<9

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L. 3 What are the conditions where the TRIGA reactor is considered

" secured?" (2.25)

L.4 List three of the four interlocks associated with the TRIGA reactor listed in the technical specifications. (3.0)

L. 5 What is the time interval (daily, weekly, monthly, semiannually, or annually) for the following Tech Spec surveillance items?

a. Emergency Spray Cooling System (.75)

b. Startuo Instrumentation (.75)

c. Control Rod Worth (.75)

d. Radiation Monitoring Instrumentation (.75) 8

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hi L. 6 According to the tecnnical specifications, wnst are three of the four items that must be evaluateo prior to a proposeo experiment being performed? (2.25)

L. 7 When must the Daily Checklist be completed? (1.5) .

[. 8 Under wnat two conditions is the LOPRA considered " Inoperative?" (1.5) -

L 9 _What are the power level reouirements that shall not be exceeded on the LOPRA for.the following:

a. Steady State (0.5) c .' Peak (0.5)

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\T\ h )W ANSWER KEY UNIVERSITY OF ILLINOIS

h. REACTOR THEORY H.1 a. Triga core beta = .0073 making it larger than the 8 for U-235 but smaller than B for U-238.

O. 32:0d er . 0073 9 . 0055 '. 0073 - 30!; . 015- ' 00': - 0,1-0065 - 751 iK/". 0157 '. 5% ax/K E8

c. The neutrons have long generation time thereby making tne fission process controllable.

c. Too low on energy level for U-238 fission.

Ref: NE 390R Notes, p. 2 4 Qi - -

• (sizer As the reactor becomes effectively smaller in size, the curvature of the flux snape becomes greater ana therefore buckling increases.

Ref: NE 390R Notes H.3 Initial Decrease - Slight deficiency of the ecuilibrium fraction since delayed neutrons come from fission product precursors, it is necessary to build-in the precursor atoms until the rate of production is eauivalent to the rate of decay. The time required for this to De accomplished is related to the nalf-life of the respective precursor atom. After six minutes, the longest half-life precursor (55 seconds) will oe within 2%

of its saturated value.

Ref: NE 390R p. 10 H.4 1. time it takes to increase the power level by a f actor of e

2. material with a large cross section for absorbing neutrons, excluding fuel

3. flux shifting in core during movement of control roas causing a varying flux in different regions of the core wnich results in Buildup / Burnout of Xenon whicn will tend to shift flux again wnen rods are withdrawn Ref: NE 390R p. 11, 13, 15 H.S Keff is greater than prompt critical value chain reaction maintain on prompt neutrons alone. The reactor " outruns" the delayed neutrons and control mechanisms cannot act f ast enough to prevent this. 45* 3 Herr assa mr. Lies m.m* usunoumitu e .mu n .c o us,ms,... ra c ere,aa Ref: NE 390R Notes, p. 2

o H.6 a. Adc

o. Can acd or subtract cepending if core is under or over moderatec.

c. Subtract .

Ref: NE 390R Notes H.7 Cell effect - Increasec temperature causes narcening of neutron spectrum tnrougn collisions with Dound hydrogen in ZrH. Harcening spectrum results in a decrease in fission probability and an increase in the fraction of neutrons lost because of leakage from the element anc parasitic capture in the core water. Ano con *al loM w'W A%5E3 *0" D*jgg 7,,,4yQ,gg,4 Doppler effect - The caoture resonances in 0-238 are Droadenea by an increase in fuel temperature. causing a decrease in the resonance escape ,

probability.

Core leakage - When the core neats up, leakage is increased and relatively more captures occur outside the fuel (e.g. , in the reflector, etc. ).

Ref; NE390 R Notes H.8 a. The time netween birth of a neutron from fission and death by absorption or leakage. l

o. Fuel and moderator are in an intimate mixture means the neutron will be thermalized quickly and be in close proximity to fuel for fissioning as opposed to leaving the fuel, being moderated and returning to fuel i normal fuel / moderator configuration. (Neutron lifetime in TRIGA ~ microseconds.)

c. Shorter lifetimes, larger peak pulses attainaole before negative coefficient snuts it cown.

Ref: NE 390R Notes

m Answer Key - University of Illinois I. RADI0 ACTIVE MATERIAL HANDLING, DISPOSAL, AND HAZARDS I .1 a. 1 200 mr/hr

b. i 100 mr/hr

c. 50 - '- Scco c>m ou T41 @ NE

a. 20 mr/hr Ref: TS, Section 3.0 1.2 a. Major portion of body receive in one nour a cose > 5 mr.

D. Major portion of boay receive in one hour a cose > 100 mr.

Ref: 10 CFR 20 s...a ze 1.3 a. alarm - 100.000 com oa 7"0V"d ele. ; 10,000 cau #

o.  :!:r - centinuous celsing of the bel' and red tights-t#

alert - several pelec 're : bell , #

a--reddight ea air earticulate =^aiter #

-eee4ight--on-reacter cen:cle fe!!cece by a-flashing yelled 1;nst in sne s a;,-e+ ; n- 6

?wr a f.uet.-ec,44uh --idhimeisfidas e anu/Memuur Ref: FSAR,Section XI I.4 rubidium-88 Ref: FSAR,Section XI I.5 a. Any radioactive material yielded in or made radioactive by exposure to the radiation incident to the process of producing or utilizing specialnuclearmaterial(measureoftnedoseofanyionizing g g b, radiation to oody tissues in terms of its estimated biological effectrelateivetoadoseof1roentgenorXrays.)

b. Rad x QF

c. absorbed energy - 100 ergs /gm measure of the dose of any ionizing radiation in terms of the energy absorbed per unit mass of the tissue.

Ref: 10 GFR 20 3

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I.6 a. Film Dadges and self reading pocket dosimeters,

b. < 8 hrs / week - issued pocket dosimeter Visiting groups - 1 dosimeter /every 10 people Ref: TS XI-26 -

I.7 -Reactor Supervisor Reactor Health Physicist Ref: XI-26 I.8 Ar-41 Ref: TS XI-6 I.9 4 floor drains 1 trench drain -

cleanuo shower cleanuo sink Ref: TS XI-3 1.10 1. Dose to whole body shall not exceed 3 rems

2. Shall not exceed 5(N-18)

3. Form 4 completed Ref: 10 CFR 20.101 se 4

Answer Key - University of Illinois J. SPECIFIC OPERATING CHARACTERISTICS J.1 Lower (0.5). The instruments are now seeing more leakage neutrons due to less dense moderator. Tnerefore they read higner at lower actual power.

Ref: NE 390R Notes J.2 Attributed to the formation of a slight gao between fuel and cladding causing poorer neat conduction from the fuel-moderator to the cladding.

Ref: NE 390R Notes

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J.3 Forced circulation affords 'n'igher achievable power levels due to' lower

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fuel temperatures and thereby lower fuel temperature defect. --

Ref: NE 390R Notes J.4 a. The bubbles would be treated as voids and since TRIGA has a negative void coefficient the rods would be pulled to maintain power constant.

b. The effect from an extraneous neutron source would be negligible and no control rod action would take olace.

Ref: NE 390R Notes J.5 See attacned sketch.

Ref:

J.6 (1) The simultaneous withdrawal of more than two motor-driven rods in the steady-state mode. This prevents the insertion of reactivity at a rate where control of the power level may be lost by the operator.

This is especially true during operations previous to the appearance of the reactor period information, which occurs at about one watt.

(2) The removal of either transient rod with the other rods removed from their down position in the steady-state move. This oreVents undesired transients that result from an operational error. Although the system would be protected by the power level and period scrams, the information recorded for transients would be lacking and hence the results would be unknown.

(3) The application of air to the adjustable transient rod unless the rod cylinder is fully inserted int he steady-state mode. This limits the rate of reactivity insertion during startuo in to its maximum up position. The second rod (adjustable transient) must be mechanically removed with the rod cylinder.

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(4) The movement of any control rod except the transient rods in the pulse mooe. This.is a safety feature that prevents insertion of additional' reactivity just previous to a transient. When the reactor is placed in the pulse mooe. information on the power level -

is lost until-a power level in the megawatt region is ootained ano -

the first indications of increases in the fuel temperature appear.

Without the interlock, it is conceivable that a manually operated rod could be withdrawn accidentally and thereby result in a transient considerably higner than expected.

(5) The performance of a pulse or the initiation of a square wave with the steady state reactor power able 250 kilowatts. This prevents an occurrence wnere the maximum fuel temperature might exceed the safety limit. The present limit of 250 kilowatts allows some flexibility for transient operation, while still assuring that excessively nigh temperature won't occur even if a maximum transient ,

is operated from this level.

Ref: NE 390R Notes J.7 Electrical dynamic ano static braking on motors provioe fast stops ano to limit coasting or over travel.

Ref: FSAR J.8 % power switch - calibrate - reads 100%

Ref: FSAR J.9 a.

Rxwatertanklevel(scramiflevelabovetopqridplabeifcoreis less than 14 feet. 16" Aun 20" - normdl o ILft)

b. Water temperature scram if bulk water temperature in tank or exit coolant temperature > 120*.

Ref: FSAR J.10 Reactor checkout procedure ll.e - Start Drimary pump 11.g - Check Flapper Valve is closed 11.h - Stop primary pump 11.j - Check Flapper Valve is open Ref: FSAR 6

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' f t..f% .

( r.a r.:t r : :s cc at + c s itt boroo enrictied ir, the f20 2 s ol c.pe and 25

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uncoatec anc 25 s.e n5 212 ve only tc gam:r.a. b3 c oruiect 2 nr the t ut, ch.n. tie r s

5. t hat the i t out nut currents buck (the currents electr2cally oppose e.r ot s.e r s thet the net eiertrical output or current t rer the chamber

. . e tie aiittrc." s ur: of the twc. icos tat 2 ori c ur r ent t

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- ic it ta rese c 2 a t e recret a re rene rally unoerec.mnensated (-65', compensatec

ir-IF

a

: .h ic Tr.is means currern trot be r or. 1 : nec c o an.oe r 2 Freate: tr.ar. current troc utai n ned c hamner n r. a g anana 12eic.

O Answer Key - University of Illinois K. FUEL HANDLING AND CORE PARAMETERS  :

K.1 a. 15 elements 1

b. K = .6 by y_g; M = y_1g,130 12

• l-X, 2.5 = y_A K = 2.

=.6

c. Too close; the multiplication in the reactor is initially Deing masked by the strength ,0f source neutrons ,

Ref: NE 390R Notes -

K.2 Allows smaller overall dimensions of core and prevents flux oeaking; increases worth.

Ref: NE 390R Notes K. 3 a. Control rod - Fuel follower - air void, borated graphite, fuel, air void Fast Transient rod - (borated graphite double section), air void Adjustable transient rod - borated graphite, air void

b. The air follower serves to diminish the flux peaking that would occur in the water filling the region wnen the too is withdrawn.

Ref: FSAR K. 4 Linear Power Instrument failed low, log N seeing increase in power since rod is being withdrawn by the linear power instrument.

Ref: FSAR K. 5 By the use of a source interlock on the startup detector requiring minimum counts.

Ref: FSAR K.6 a. The standard fuel elements shall be measured for length and bend at intervals separated by not more than 500 pulses of magnitude greater than $1.00 of reactivity. Fuel elements in the B and C hexagonals shalt be measured at intervals not to exceed 12 months. Low nydride fuel elements shall be measured at intervals separated by not more than 50 pulses or 12 months if they are used for pulsed operating in the TRIGA core.

7

c. A fuel element indicati'gn an elongation greater than 1/4 of an incn over its original lengtn or a lateral bencing greater than 1/16 of an inen over its original bending snall be considered to be damaged and shall not be used in the core for further operation. -

c. Fuel elements in the B- and C- hexagonals shall be measurea for -

possible distortion in the event that there is indication that fuel temperatures greater than the limiting safety system setting on temperature may nave oeen exceeced.

Ref: TS, 4.0 K. 7 a. Standard Fuel Element: The standard fuel element shall contain uranium-zirconium nycride, clad in 0.020 igh of 304 stainless steel. It snall contain a maximum of M 7eight percent uranium wnichhasamaximumenriennentof20pdhcent. There shall be 4 44 Lad 944u 1.30 byarogen atoms to 1.0 zirconium atom.

I.1

b. Low Hydride Fuel Element: This fuel element shall contain uranium-zirconium nyaride, clad in 0.030 inch of aluminum or 0.020 jnch of 304 stainless steel. It shall contain a maximum of A(peight percent uranium wnich has a,3aximum enrichment of 20 percent. There shall be G.3 6v 1.54 hydrogen atoms to 1.0 zirconium atom. b7 Ref: TS, 5.0 e

8

Answer Key - University of Illinois L. ADMINISTRATIVE PROCEDURES, CONDITIONS AND LIMITATIONS L.1 a. $8.00

b. $1:00

c. $5.00

d. $10.00

e. $5.00 ,

f. 1 second

g. 1 cpm Ref: TS Section 3.1

~

L. 2 a. Transient roos are set such that their reactivity worth upon withdrawl is not greater tnan $4.60.

b. Temperature of the fuel immediately prior to the pulse is less than 250*C as measured in the thermocoupled fuel element in the B-hexagonal or 235*C in the C-hexagonal or 211*C in the D-hexagonal.

Ref: TS Section 3.3 L. 3 a. The reactor is shutdown.

o. Power to the control rod magnets and actuating solenoids nas been switched off, the key removed.

c. No work in progress involving fuel or in core experiments or maintenance of the core structure, control rods or Control Rod Drive Mechanisms.

Ref: TS, XV-2 L.4 3/4 at .75 each

a. In the manual or " steady-state" mode only two control rods may be raised at any one time.

b. Except for the pulse mode, the transient rods cannot be raised with any of the other mechanical control rods above the fully insertec posi tion.

c. Mechanically driven control rods cannot be withdrawn with less than 1 cos on the startup channel.

9

I

d. A pulse cannot be initiated when the power level exceeds 266 Kw.

LCf (Any three 1.0 each)

Ref: TS XV-13 L.5 a. Weekly

b. Daily

c. Semiannually

d. Weekly Ref: TS, XV

'~ ~

L. 6 3/4 @ .75 each

_ a. Reactivity worth of the experiment D. Integrity of the experiment including the effects of changes in temoerature, pressure or chemical composition.

c. Any physical or chemical interaction that could occur with the reactor components.

d. Any radiation hazard that may result from the activation of materials or from external beams.

Ref: TS XV-29 L.7 a. Prior to each day operation

b. 100 hrs of extended operation Ref: Written Procedures - Daily Checklist L. 8 a. Sufficient fuel has been removed from the assembly to assure that Keff < 0.99 with all safety rods, poison rod, and measuring cevices removed from the core region.

o. The LOPRA has been decoupled from the TRIGA by placing a neutron absorbing curtain, equivalent to 20 mils of boral, between the assembly and the graphite column and/or by moving the assembly away from the graphite column to provide at least the equivalent effect.

Ref: FSAR Section 10 ca r4, Web L. 9 a. 250 Kw

- (.gbM)heem ear ene Mpod

b. 1000 Mw 10MW Ref: TS, Section 2.1 10