ML20138L592

Proposed Tech Spec Changes,Including Section 3.1 Re Reactivity Limits & 3.9 Re Fission Density Limit

ML20138L592
Person / Time
Site:	University of Michigan
Issue date:	02/28/1985
From:	MICHIGAN, UNIV. OF, ANN ARBOR, MI
To:
Shared Package
ML20138L505	List: IA-85-587, Submits Detailed Definition of design-basis Event, as Applicable to Facility.Licensee Should Use Definition to Show That Proposed Low Enriched U Loading Will Not Result in Significant Release of Radioactivity ML20138L502 ML20138L512 ML20138L518 ML20138L524 ML20138L549 ML20138L553 ML20138L557 ML20138L562 ML20138L567 ML20138L573 ML20138L579 ML20138L589 ML20138L592
References
FOIA-85-587 NUDOCS 8512190307
Download: ML20138L592 (12)

Text

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.r TECHNICAL SPECIFICATIONS

Ford Nuclear Reactor

j Docket 50-2, Li, cense R-28 ,

] November, 1984 )

s.  ;

i Static Reactivity Worth - The static reactivity worth of an j , experiment is the absolute value of the reactivity change which is 1i measurable by calibrated control rod comparison methods between j' two defined terminal positions or configurations of the 1l" experiment. For moveable experiments, the terminal positions are j f ully removed f ron. the reactor and fully inserted or installed in 7  :; the normal functioning or intended position.

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I Time Intervals h! -

J .] Annually - 12 to 15 months.

tj 1 Biannually - 24 to 30 months.

Daily - 24 to 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />.

.J ]

.1 4 1 1 Monthly - 30 to 40 days.

11 fl i i Quarterly - 3 to 4 months.

.3

1. Semiannually - 6 to 8 months.

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Weekly - 7 to 10 days.

I 1' True Value - The true value of a process variable is its ac'tual value at any instant.

Unscheduled Shutdown - An unscheduled shutdown is defined as any unplanned shutdown of the reactor caused by actuation of the reactor safety system, operator error, equipment malfunction, or a manual shutdown in response to conditions which could adversely j i affect safe operation, not to include shutdowns which occur during

[ [ testing or checkout operations.

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!! 8512190307 851203 PDR FOIA

?l 1 ^FTERGOB5-587 PDR 3i '

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TECHNICAL SPECIFICATIONS

.: Ford Nuclear Reactor i ~

.i Docket 50-2, License R-29 j .' "

November, 1984

3.

id 1

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3.0 LIMITING CONDITIONS FOR OPERATION

,a  ! 3.1 Reactivity Limits d.4j j Applicability d

(j3 This specification applies to the reactivity of the reactor 33 core and to the reactivity worths of control rods and experiments.

N When the reactor is operated with the heavy water reflector tank

[j in place, the limits will not include the stctic reactivity worth of the tank.

y j Objective

'1 1

.1'; To assure that the reactor can be controlled and shutdown

'd ) '

at all tim.es and that the safety limits will not be exceeded.

_i . Specification:

1 (1) The shutbown margin relative to the cold, xenon free Jj j critical condition shall be at least .025 delta K/K with a : all three shim saf ety rods fully inserted and the l regulating rod fully withdrawn and 0.0045 delta K/K with U i

• the most reactive shim safety rod and the regulating rod

. fully withdrawn.

j - (2) The overall core excess reactivity includino 1 moveable experiments shall not exceed 0.038 delta K/K.

1 yj (3) The total reactivity worth of all experiments shall not j; s exceed 0.012 delta K/K.

(4) The reactivity worth of each experiment shall be limited 7

as follows:

k l.

}'u, Maximum q> Exoeriment Reactivity Worth n

9' Moveable 0.0012 delta K/K f, Secured 0.012 delta K/K a ,

j (5) The reactor shall be subcritical by at least 0.03 b,.

delta K/K during fuel loading changes.

N (6) Shim safety rods shall not be removed from the core for 1; inspection if the shutdown margin is less than 0.01

! delta K/K with the most reactive remaining shim *s'Af'ty

'- .}, .i rod fully withdrawn.

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(7) The reactivity worth of the regulating rod shall not

' l exceed 0.006 delta K/K.

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TECHNICAL SPECIFICATIONS -

.,: Ford Nuclear Reactor f.] Docket 50-2, License R-28 a November, 1984 4

fj ,

exposure, inside a blast proof enclosure. The enclosure will not

.:  ; be coupled to the beamtube or beamport and will be constructed to

' ; j .J fully contain any blast effects or missiles which might be  ;

3 j generated by an accidental detonation. '

3 4 Specifications 3.8.(5) and 3.9.(6) conform to the regulatory 1

.; ~j position put f orth in Regulatory Guide 2.2 issued November, 1973.

The calculations f or experiment radioactivi ty limits are provided

[ in section 14.5 of th e S At- E T Y ANALYSIS.

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3 3.9 Fission Density Limit d +

Applicability:

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This specifica. tion applies to fission density limits in FNR

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,: I fuel.

if Objectives 71 i k" t To prevent fuel plate swelling which could result in clad

i. ; rupture and release of radioactive fission products.

~

Specification r} (1) The FNR fission density lim'it shall be 1.5x10**

j fission /cc.

. Bases:

h The fission density limit is below operational fission 3, densities reached it' other operating reactors using the same kind N? of fuel without failures, attributed to the fuel.

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' An experimental data base which supports the saf e use of UA1 and .U,0. f uel in the FNR up to the fission density was P) '; derived from irradiation tests performed in the Materials Test I

H Reactor (MTR), the Engineering Test Reactor (ETR), and the Advance Test Reactor (ATR) at the Idaho National Engineering Laboratory, the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory, and the German Karlsruhe FR2 reactor.

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- l SAFETY ANALYSIS b.t Ford Nuc1 par Reactor

3 Docket 50-2, License R-28

] September, 1984 ti!

9 1

14.2.4 Beamports 13 There are eight six-inch diameter and two eight-inch

diameter aluminue beamports labeled A -J. The beamports penetrate y' the pool wall in a staggered arrangement at f our dif f erent heights

/ and terminate on the reactor's heavy water tank as shown in Figure.

d 9.1. The four heights at beamport centerlines when referenced to yj 7.; i the bottom of active fuel in the core are 0.38, 1.0, 1.61, and 2.28 feet. If the pool level reached the lowest elevation in the

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lowest beamport, active fuel would remain immersed in approximately two inches of water and the bottom of the core would p be immersed in approximately three and one-half inches.

. .q Beamports are configured as in Figure 14.1. Four

% barriers to loss of coolant can be provided; not all beamports l' have all four barriers. The f'irst barrier is the beamtube itself.

N

'i A collimator is sealed into the beamtube for the purpose of reducing an extracted neutron beam to a desired cross sectional area. The collimator can have watertight barriers at the pool end and the outer end. The beamport shield door serves as the f ourth barrier, but the door is raised when a beamport 'is in use which j eliminates its utility.

[' At the Ford Nuclear Reactor, every beamport is g

configured with at least two of the barriers labeled one, two, and

'q three in Figure 14.1, except I beamport. ,I beamport has a i twenty-nine inch long collimator which is open at both ends.. The A outer aperture is a one-half inch by one and one-fourth inch j . rectangle.

)J W In all of the beamports, the collimators do not L.

extend beyond the concrete pool wall. Even if the beamtube were sheared off, the collimator would remain intact to prohibit loss a of coolant, with the exception of I beamport.

)

E I beamport is shown diagramatically in Figure 14.2.

The centerline of the beamport is 1.61 feet above the bottom of d active fuel in the core. If the pool level drained to just Pi below this centerline, active fuel would remain immersed in f; approximately eighteen inches of water.

q 14.2.5 Fneumatic Tubes 9

j A bundle of eight,' one and 7/16 inch diameter, H pneumatically operated, aluminum, sample irradiation tubes K, penetrate the pool floor and terminate adjacent to the west face l

[j, of the reactor core.. A typical set of two tubes can be seem in '

H Figure 9.1 on the left side of the core.

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SAFETY ANALYSIS 1 Ford Nuc1' ear Reactor ll Docket 50-2, License R-28 f.j September, 1984

• I

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Flow rate through a rupture equals the rate at which l f the pool level drops times the surface area of the pool.

a w = -A. dh/dt (14.5)

(

n where:

u d A. = Pool surface area, 210 ft*.

1 Substitute w from equation (14.3) into equation i (14.5) and separate variables.

M d dt = -(A./A 4 2 gh) dh (14.6)

, To calculate the drain time from an initial pool M water level down to a lower level, integrate equation (14.6) between the two levels.

ti 1 .

t= (4 2 A./A 4 g) (4 h. - 4 h) (14.7)

, wherer t = Drain time, sec;

h. = Initial pool level above rupture, ft;

, h = Final pool level above rupture, ft; k Convert drain time to hours.

t= (.0145/A) (4 h. - 4 h) (14.8)

~1 Calculations for flow rate, equation (14.4), and

!.j ' drain time, equation (14.8), for I beamport and one pneumatic tube c' are summari:ed in Table 14.1. These two parameters are

'I calculated (1) shortly after rupture has occurred when the pool i level has decreased one foot below normal to the level scram '

setpoint; (2) when the pool level reaches the top of the core;

? and, (3) when the pool level reaches the bottom of the core. In the case of I beamport, level will not recede below the beamport

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which is 1.61 feet above the bottom of active fuel and 1.78 feet above the bottom of the core as can be seen in Figure 14.2. I d

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• y The maximum flow rate as the result of the rupture 1 of a 1-7/16 inch diameter pneumatic tube with the pool level 27.94 i feet above the opening where the draining occurs is 209 gpm. In

, this most severe case, with no emergency makeup flow""The core j remains completely covered for Jgjg, hours and partially covered q f or 3.58 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br /> f ollowing an automatte low pool level scram. By d

a the TIIE*the core begins to uncover, fission product decay heat t

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c SdFETY ANALYSIS q Ford Nuclear Reactor

• Docket 50-2. License R-28

-4 a September, 1984 i

)

1 Table 14.1 Flow Rates and Drain Times Corresponding to Various Reactor Pool Levels for

.i Ruptures at I Beamport and One Pneumatic Tube

j Pool Level Flow Rate Drain Time

',.j (ft above rupture) (qpm) (he) 1 d I Beamoort 9:'

Pool Level Scram 19.56 69 0

Level at Top of Core 0.56 12 12.39 i Level at Beamport Centerline 0 0 14.91 4

Q Pneum & tic Tube 4

i Pool Level Scram 27.94 -

209 0 Level at Top of Core 8.94 -

119 3.03 Level at Bottom of Core 6.60 -

102 3.58 r,

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j SAFETY ANALYSIS Ford Nuclear Reactor Docket 50-2, License R-28 3 September, 1994

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>J c will have decreased form about seven percent of full power at i shutdown to less than one percent of full power.

3

,14.2.7 Emergency Makeup Water

, Emergency makeup for the reactor pool is provided by i; a four inch water main that enters the reactor building. The four 4 inch line reduces to three inches and eventually branches to three Y. three-inch lines that supply emergency pool water. Calculations

,1, using the fire protection handbook and accounting for valves, N

elbows, and tees in the lines show the emergency makeup flow rate to be approximately 600 gpm. This flow rate is almost four times

greater than the maximum loss of coolant flow rate in Table 14.1.

3 14.2.8 Conclusions

( '

Abnormal loss of coolant from the Ford Nuclear Reactor pool that could result in partial or total uncovering of the core can be caused by a rupture in or damage to I beamtube or the pneumatic tube system. The maximum loss of coolant flow rate, from a pneumatic tube failure, is 162 gpm. The emergency makeup water system, with a flow rate of approximately 600 gpm, exceeds the loss of coolant flow rate by almost a factor of four. If emergency makeup water were not utilized, the reactor core would remain completely covered for 3.92 hours0.00106 days <br />0.0256 hours <br />1.521164e-4 weeks <br />3.5006e-5 months <br /> subsequent to a pool level scram at which time fission product heat would have decayed to less than one percent of the two megawatt normal operating

.] power level. Based upon this analysis, the most severe abnormal 1 loss of coolant event at the Ford Nuclear Reactor would not cause j core damage.

N L

14.3 Failed Experiment y

': Limits are placed on the radioactivity content of gaseous,

', particulate, and volatile reactor experiments to ensure that the

.! exposure of workers in the restricted area and the general public

.j will result in doses below 10CFR2O limits in the event of an (j experiment failure.

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d 14.3.1 Experiment Radioactivity Limits Based Upon Exposure to Personnel Within the Restricted Area of the FNR

] Building li 14.3.1.1 Assumptions

?

a. Restricted area MPC (MPCn) produces a i}j} dose of 5 rem / year for the isotope involved based upon 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> /* year l

j j exposure.

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SAFETY ANALYSIS Ford Nuclear Reactor -

Docket 50-2, License R-28 September. 1984 N

1 -

b. Volatile er dispersible activity in a 9, pool experiment is uniformly dispersed 2

?; in the lower 1/4 of the pool floor j volume.

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c. Pool floor volume, V, is approximately 58,000 cubic feet or

{,] ; 1.6x 10' cc.

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,, d. Personnel require nd more than 0.1 ij' hour or 6 minutes to diagnose the j experiment failure, initiate building 1 evacuation, and evacuate the reactor j building.

j e. Calculations are-based upon single

')

encapsulation of experiments. The l

,; allowable dose fraction for single q '

encapsulation based upon Technical Specifications is 0.1 MPCs.

'i 3 14.3.1.2 Calculations

-l

{e The concentration of radioactivity, C, permitted in the reactor building air ist C= (T/t) (0.1 MPC=) pCi/cc (14.9) j = 2000 MPC , -

1

] wheret i i

'.' T = 2000 working hours per year; -

.j t = Exposure time, 0.1 hr.

The total activity, A, of an experiment i

based upon the concentration and volume into which it is dispersed

-j is:

. )

^

A = CV/4 (14.10)

= 8.0 x 10** MPC pCi 1

]g 14.3.2 Experiment Radioactivity Limits Based Upon Exposure to Personnel in Unrestricted Areas

'A j 14.3.2.1 Assumptions **

4

a. Unrestricted area MPC(MPCu) produces a f, dose of 0.5 rem / year based upon l continuous exposure.

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4 SAFETY ANALYSIS Ford Nuc1' ear Reactor Docket 50-2, License R-28 e

4, September, 1984  :

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b. Stack dilution is 400.

h: c. The maximum rate at which air can be d' '

exhausted from the FNR following l M

initiation of building evacuation is y] 300 cfm based upon opening the exhaust L

jj duct for the hood in Room 3103.

1 5l d. The PML exhaust fan flow rate is

11,000 cfm. Room 3103 hood airflow is 1 *} -

diluted by this flow.

d} ~

j e. Calculations are based upon single 3, encapsulation of experiments. The di allowable dose fraction for single

] encapsulation based upon Technical V Specifications is 0.1 MPCu.

d.

A !

l' f. The unrestricted area is continuously

.I i occupied for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following the j, experiment failure.

i 1 . ., g. Volatile or dispersible activity in a j'

pool experiment is uniformly dispersed

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in the lower 1/4 of the pool floor

'j; volume.

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• h. Poo? floor volume, V, is approximately 58,000 cubic feet or 1.6x10' cc.

J

-l i. MPC= is approximately 40 MPCu. '

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g, 14.3.2.2 Calculations

') The allowable ~ ground level concentration

]- of radioactivity, C., is:

C. = C (365) (24) /23 (0.1 MPCu) pCL/cc (14.12) 3

.) The allowable stack concentration, C.,

q based upon a 400 dilution factor ist .

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- C. = 400 C. (14.13)

=

400 C (365) (24) /23 (0.1.MPCu) pCi/cc j ,

The allowable exhaust hood concentr,ation, C, based upon mixing with the remainder of the PML exhaust in the

,]' stack ist

,s.

f C= (11,000/300)C.

(f i, (14.14)

= (11,000/300) 400C (365) (24) /23 (0.1 MPCu) '

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SAFETY ANALYSIS 1 Ford Nuclear Reactor

! Docket 50-2. License R-28

-j , September,~ 1984 l'

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,3 = 6.42x10* MPCu pCi/cc A

d Assuming no fresh air is introduced into IS ! the pool floor and that the radioactivity undergoes no decay, the )

{jj total experiment activity, A, allowed would bas

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.: A = CV/4 (14.15)

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-1 = 2.57x105" MPCu g4

= 6.42x10$* MPCn pCi

. I 14.3.3 Limits on Single and Double Encapsulation

."j.. ?r Experiments

' "l hi Comparison of equations (14.10) and (14.15) shows

$1l that the total radioactivity for an experiment with single Mi encapsulation is limited by exposure to personnel within the 4 restricted area of the reactor building. The microcurie content

l of any experiment is calculated using equation (14.10) and MPC.

j .! values from 10CFR2O for the isotope involved.

i

, -l For double encapsulation experiments, the dose

~lj f raction i's increased from O.1 MPC= to MPCn because the double tj barrier decreases the probability of experiment failure.

<! i Theref ore, the total radioactivity content of an experiment with jJ double encapsualtion is limited to ten times the content of an

.) 1.i experiment with single encapsulation.

.1 3

!! In the event that an experiment contains more than Jj j one releasable isotope, i!

ECAa/(As)ss.. 3 1 i (14.16)

.' 1 l jq' wheres

), As = Actual isotope radioactivity, pCip

( As ) s s.s. = Equation (14.10) radioactivity limit, pCi.

14.3.4 Fissile Material Experiment Activity Limit a

/l A review of 10CFR2O limits of fissile materials and

?D, 1 their fission products shows that iodine-133 has the most fd restrictive limit due to its biological impact. In placing

?i activity limits on. fissile material or fueled experiments,,the

[j ' assumption is made that the entire fission yield is iodine-133.

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- .i . SAFETY ANALYSIS Ford Nuc1' ear Reactor 4.

i Docket 50-2, License R-28

-: , September, 1984 1

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A calculation follows to determine the combination i of fissile material weight, neutron flux, and irradiation time l' that will produce an amount of iodine-133 activity equal to the

? ]' limit in equation (14.10). Specific values for U235 are provided as an example.

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14.3.4.1 Calculations

<1

%, The fission reaction rate, R, is given by:

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-] R = Nr0 (14.17) 4 -

= 1.48x10-* WO U235 fissions /sec

., where:

, N = Atoms of fis'sile material; 3 = WA./M; .

i I

W = Sample weight, mg;

'I -

]} A. = Avogadro's number, 6.02x 10** atom / mole;

!2 -

1 M = Molecular weight, mg; 1

.h i - 235,000 mg for uranium-235; 1.

e = Microscopic fission cross section, cm";

f.

• 2

, = 577x10-** cm" for uranium-235; 4 *

.i O = Therinal neutron flux, n/cm a j,,c,

,s d1 .

,; The total number of fissions, F, in a z, , given irradiation time is:

1..

jj '

F = Rt (14.18) o i = i.40x10-* W0t U235 fissions -

i l2 ,

where

• t = Irradiation time, sec.

/1 .

Two fission products result per fission,

};

• so the total number of fission products produced, FP, is: ,,

..c .i l1 FP = 2F (14.19) 3I

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= 2.96x10-* W0t U235 fission products

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1J g , ' SAFETY ANALYSIS

,' Ford Nuclear Reactor .

j Docket 50-2, License R-29

? September, 1984 -

j . The decay rate, D, of radioactive fission q -l products is proportional to the half-life, Tz, of the isotope 1 j i .1vol ved . Since it was assumed that all fission products are il ! 1133, the 1133 half-life of 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> is used. The value of 20 Ij ' hours is reasonably representative of the average half-lif e of all fission products.

i. D = L FP (14.19)

[j ,

= (in2/T3 ) FP a .

II '

= 2.85x10-* Wet U235 disintegrations /sec

- where:

4 Lt j L = Fissile .natorial decay constant, sec-S;

= In2/ Tag 1 .

! 1 Tm = Fissile material half-lif e, sect

' I,

'!j = 7. 2x 10* see f or I133. -

1 ^ ,'

} Experiment radioactivity, A, is obtained by converting the decay rate to microcuries.

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t

! A = D/3.7x10* pCL (14.20)

= 7.7x10-5* Wet pCi I133

]i The combination of fissile material q' . weight, neutron flux, and irradiation time permitted is determined by setting equations (14.10) and (14.20) equal. For the specific example of U235 and its fission product, 1137,

]3l.

Eri ! 7.7x10-S* Wet = 8.0x10** MPC.

3) -

I Wet = 1.04x 10** MPC.

I = bx 1 * (single encapsulation)

?I 1.1% lW t4 = W x10** (double encapsulation)

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}j f where

( MPC. = 2-10-* pCi/cc for 1133. i I

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