IR 05000134/1986002
| ML20210U271 | |
| Person / Time | |
|---|---|
| Site: | 05000134 |
| Issue date: | 09/26/1986 |
| From: | Coe D, Keller R, Kister H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20210U268 | List: |
| References | |
| 50-134-86-02OL, 50-134-86-2OL, NUDOCS 8610090470 | |
| Download: ML20210U271 (13) | |
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U.S. NUCLEAR REGULATORY COMMISSION REGION I OPERATOR LICENSING EXAMINATION REPORT EXAMINATION REPORT N (0L)
FACILITY DOCKET N FACILITY LICENSE N R-61 LICENSEE: Worcester Polytechnic Institute 100 Institute Road Worcester, Massachusetts 01609 FACILITY: WPI Facility EXAMINATION DATE: August 29, 198 CHIEF EXAMINER [)
.' Coe, React'6r
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e 9//f/Sif date
'eer (Lead Examiner)
REVIEWED BY: 9//ff/74 R. K611er, Chfef,' Projects Section 1C 'date APPROVED BY is JM, H5rry B. Kf\ter, Chief ' dat'e Projects Branch No. 1 SUMMARY:
One R0 candidate was administered a written examination for Section A which he passed. The examination was administered in the Region I office. A copy of the examination and answer key was mailed to the facility for the post-examina-tion review. No comments concerning the examination questions were submitted by the facilit "~
8610090470 860930 PDR V
ADOCK 05000134 PDR
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REPORT DETAILS
' TYPE OF EXAMS: Initial Replacement X Requalification EXAM RESULTS:
l R0 I SR0 l . Inst. Cert l Fuel Handler l l Pass / Fail l Pass / Fail l Pass / Fail l Pass / Fail l l l l l l l l l l l l IWritten Exam l 1/0 l / l / l / l l l l l l l I I I I I l Oral Exam l / l / ,l / I / l l 1 I I I I I I I I I I l Simulator Examl / l / I / I / I I I I I I I
- I I I I l l l0verall I 1/0 l / I / l / I I I I I I I I I I I I I CHIEF EXAMINER AT SITE
- D. Coe OTHER EXAMINERS: D. Silk
Attachment:
Written Examination and Answer Key (RO)
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U. 5. NUCLEAR REGULATORY COHH1SSION REACTOR OPERATOR I.ICENSE EXAMINATION F ACIL IT Y : WORCESTER POLY. INSlITUTE
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REACTOR TYPE! TEST
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DAfE ADMINISTERED: 86/08/29
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EXAMINER: sit.K , 0, CANDIDATE: . . . . D. .'i. . '.' . . . .c }(? y. . . . . . . .
INSTRUCTIONS TO CANDIDAIE;
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Use separate paper for the anseer Write answers on one side onl Staple question sheet on top of the ansuer sheets, Points for each question are indicated in parentheses after the question. The passing grade requires at least 70% in each category. Examination papers uill be picked up si:: (6) hours after the examination start % OF CATEGORY % OF CANDIDATE'S CATEGORY VALUE TOTAL SCORF VALUE CATEGORY
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15.00 100 0
--_----- -. 1.0 _ ----__.. ._ ________ PRINCIPlFS OF REACTOR OPERATION
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15.00 Totals
---._- Final....-..-- .Grado All uork done on this examination is my ou I have neither given not received ai .--.-.-----. -----.. .....
Candidate's Signature
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NRC RUl FS Ail.D GLIIDEL INES FOR L ICFHSF EXAMINAlIONS During the administration of this examination the following rules apply! Cheating on the examination means an automatic denia) of your application and could result in more severe penaltie ?. Restroom trips are to be limited and only one candidate at a time may leav You must avoid all c o n t a c t.s with anyone outside the examination room to avoid even the appearance or possibility of cheatin . Use black ink or dark pencil oril / to facilitate legible reproduction . Print your name in the blank provided on the cover sheet of the examinatio . Fi]] in the date on the cover sheet of the examination (if necessary). Use only the paper provided for answer . Print your name in the upper right-hand corner of the first page of each section of the answer shee . Consecutively number each answer sheet, write 'End of Category __' as appropriate, start each category on a new pager write only on one side
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of the paper, and urite 't.ast Page" on the last answer sheet, c...
. Number each answer as to category and number, for example, 1.4, . Skip at least thre e lines between each answe . Separate answer sheets from pad and place finished answer sheets face down on your desk or tabl . Use abbreviations only if they are commonly used in facility literatur ..........
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13. The point value for each question is indicated in parentheses after the question and can be used as a guide for the depth of anseer require . Show all calculations, methods, or assumptions used to obtain an answer to mathematical problems uhether indicated in the question or no . Partial credit may be give Therefore, ANSWER All. PARIS OF file OUFSTION AND DO NOT lFAVF ANY ANSWER PLAN . If parts of the examination are not clear as to intent. asi questions of the examiner onl ........
17 You must sign the statement on the cover sheet that indicates I.h a t the work is your own and you have not received or been jiven assistance in completing the examinatio This must be done after the cuaminatinn has been complete ..
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10. When you complete your examination, you shall Assemble your examination as follous; (1) Exam questions on to (2) Exam aids - figures, tables, et (3) Ansuer pages including figures ehich are part of the answe Turn in your copy of the examination and all pages used to answer the examination question Turn in all scrap paper and the balance of the paper that you did not use for anseering the question d, leave the examination area, as defined by the examirier , If after leaving, you are found in this area chile the examination is still in progress, your license may be denied or revoked,
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. PRINCIPlFS OF RFACTOR OPERATION PAGF ?
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QUESTION A.01 (?.00)
Explain how natural circulation occurs in the WPI reacto (JUFSTION A.0? (1.50)
The resetor goes from 100 watts to 8000 watts in tuo minutes. Given that A= 0.08 sec^-1 and /7 = 0.0065, calculate the amount of reactivity that was added to cause this rate of power increas Show a)) eork and state all assumption DUFSTION A.03 (3.00) In a soberitical reactor reactivity is added to cause the count rate to double. What uov1d be the effect on the reactor of adding the same amount of reactivity again? Fxplai (1.5) A detector, located next to a core with a source, reads a constant 1000 counts per secon The source is removed and the count rate begins to decrease. Was the core critical? Explai (1.5)
00FSTION A.04 (1.50)
At a steady state power level, are all the fuel elements producing the same power? Explai .
uuf5 TION A.05 (?.50)
, In a soberitical reactor, does the speed at which the control rods are withdrawn affect the rods' positions when criticality is achieved? Fxplai (1.0) Which figure of Attachment 1 best represents the reactivity inserted per unit distance of rod uithdrawal (differential rod oorth) and ex-plain the basis for the share of the curve? (1.5)
00ESTION A.04 (1.50)
If 1% excess' reactivity is added to a reactor that is critical, the re-sulting period is very shot Explaire uhy the addition o f~ 1% NEGATIVE reactivity to critical reactor results in a long stable perio (***** CATEGORY A CONTINUED ON NEXT PAGE *****)
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i PRINCIPtFS OF RFACTOR OPERATION PAGF 3
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OllFSTION A.07 (?.00)
The reactor is critical at 100 watts. Explain the effect on reactor power of the beam port filling with water, utIESTION A.08 (1.00)
Describe the process by which the plutonium-beryllium source produces neutron .
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f/in C/in B distance T E distance T Figure A Figure B
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f/in C/in B distance T B distance T Figure C Figure D
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EQUATION SHEET
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f = ma v = s/t Cycle efficiency = (Networu
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+ out)/(Energy in)
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w = ag s = V,t + 1/2 at
E = ac KE = 1/2 av a = (Vf - V,)/t A = AN A=Ae**g
PE = agn Vf = V, + at w = e/t A=
an2/t1/2 = 0.693/t1/2
- t eff = [(tif.;)(t)]
s y , y ,p ifz
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[(t1/2) * (*b)3 '
aE = 931 am
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I'= I,e'**
Q = mCpat (j = UAat I * I ',,
o Pwr = Wyah I"I 10-x/TVL o
TVL = 1.3/u P = P 10sur(t) gyt . o.693/g -
p = pg et /T
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SUR = 26.06/T SCR = S/(1 - K,ff) r,
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CR x = S/(1 - Keffx)
SUR = 26o/ t* + (s - e)T CR j (1 - K,ffj) = GZII ~ "eff 2) ' -
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T = ( t*/s ) + [(a - e )/So] M = 1/(1 - K,ff) = CR j/CR, T = 1/(o - 8) M = (1 - K,ff,)/(1 - K,ffj)
T = (s - o)/(lo) SDM = (1 - K ,ff)/K,ff a = (K,ff-1)M,ff = 4K,7f/K,ff t* = 10~0 seconds
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T = 0.1 seconds-I e = [(.t*/(T K,ff)] + [i,ff (1/ + AT)]
Idli*Id2 P = (r+V)/(3 x 1010) Id j 2 ,2 gd 22 2 I = oN R/hr.= (0.5 CE)/d (meters)
R/hr = 6 CE/d2 (feet)
Water Parameters Miscellaneous Conversions 1 gal. = 8.345 lbm.~ 1 curie = 3.7 x 1010 dps 1 gai. = 3.78 liters 1 kg = 2.21 lbm 1 ft* = 7.48 ga hp = 2.54 x 103 Stu/hr Density = 62.4 lbm/ft3 1 av = 3.41 x 106 Stu/hr Oensity = 1 gm/cm3 lin = 2.54 cm Heat of vaporization = 970 Stu/lbm *F = 9/5'C + 32 Heat of fusion = 144 Stu/lbm 'C = 5/9 (*F-32)
1 Atm = 14.7 psi = 29.9 in. H BTU = 778 ft-lbf 1 ft. H 2O = 0.4335 lbf/i . . , .
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.* PRINCIPL ES OF- RFACTOR OPERATION PAGF 4
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ANSWERS -- WORCESTER POLY. INSTITLITE -86/08/?9-SILK, ANSWER A.01 '(2.00)
The core heats the eater adjacent to the fuel elements (0.6)
Warmer uater is less dense and rises up through the core (0.7)
Cooler. eater replaces the rising eater by entering at the bottom of core and the cycle continues (0.4)
REFERENCE
' Introduction to Nuclear Engineering, chapter 8; Lamarsh ANSWER A 02 (1.50)
P =~Po e^t/l P/Po = 80 = e^t/T T = ?7.4 see (0.5)
T= ([ j e)/(hj o)
/s= /P/(TA + 1) = 0.00? delta-k/k (1.0)
REFERENCE Introduction to Huc l e s'r Engineering, chapter 7, pg. 245-?56; tamarsh -
.ANGWER A.03 (3.00) By doubling the count rate 1-Koff is halved (1.0). The reactor uould be supercritical (0,5).
(Assume Keff = 0.90 at 20 eps then Keff = 0.95 at 40 ces Change in reactivity (0.05/0.9x0.95) = 5.05% delta-k/k Reactivity needed for criticality (0.05/0.9x1) = 5.55% delta-k/k 0.3% delta-k/k excess reactivity would be added) No (0.5). The constant count rate was dependent on the source neutrons, therefore, criticality uas not achieved (1.0). 6 REFERENCF Introduction to. Nuclear Engineering, chapter 7, pg.?40, chapter 4, pg ; Lamarsh i
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. PRINCIPLES OF RFACTOR OPERATION PAGF 5
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ANSWERS -- WORCESTER POLY. INSTITUTE -86/08/??-STLK, ANSWER A.04 (1.50)
Pouer production is proportional to the flux (0.5) and since the flux is unevenly distributed throughout the core (higher in the center, lower at the edges) (0,5) power production will not be the same for each fuel element (0,5).
REFERENCF Nuclear Energy, chapter 5, pg. 41; Hurray Introduction to Nuclear Engineering, chapter 6, pg. 221; i.a mar sh ANSWER A.05 (?.50) rio (0.5). The position of the rods at which the reactor becomes critical is dependent upon shutdown margin not rod speed (0.5), Figure B (0.5). Neutron population is greatest in the center of the core and less near the edges, therefore, the reactivity effect is greatest in the middle of the core and drops off near the edges (1.0).
REFERENCE Introduction to Nuclear Engineering, chapters 6 & 7; tamarsh ANSWER A 06 (1.50)
After the prompt neutrons and short lived delayed neutron precursors have decayed off (0.5), only the longest lived precursors remain and therefore dictate the period (1.0).
REFERENCE Introduction to Nuclear Engineering, chapter 7, pgs. 245-756; Lamarsh ANSWER A.07 (2.00)
Water is a better moderator and reflector than air thus causing more ther-mal neutrons to diffuse back into the core (1.0) and with mar'e neutrons -
available to cause fission reactor pooer oill increase (1.0).
REFERENCE In tr oduc tion to riu c l e a r Engineering, chapter 6, pg. ?14, chapter 4 pg ; l.a nia r sh
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. PRINCIPlFS OF REACTOR OPERATION PAGF 6
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ANSWERS -- WORCESTER POLY. INSTITUTE -86/08/?9-SIL K, ANSWER A.08 (1.00)
When Po decays it emitts an alpha particle that interacts eith De to produce C-12 and a neutron (1,0).
REFERENCE WPI 5AR pg. 24 Introduction to Nuclear Engineering, chapter 2, pgs. 17-?); tamarsh n 4
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TEST CROSS REFERENCE PAGE 1 QUESTION val.UE REFERENCE
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A.01 2.00 DXS0000300 A.0? 1.50 DXS0000301 A.03 3.00 DXS0000307 A.04 1.50 DXS0000303 A.05 2.50 DXS0000304 A.06 1.50 DX50000305 A.07 2.00 DXS0000306 A.00 1.00 DX50000307
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