ML20003H595
| ML20003H595 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/08/1977 |
| From: | Pasedag W Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20003H594 | List: |
| References | |
| NUDOCS 8105060480 | |
| Download: ML20003H595 (16) | |
Text
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ENCLOSURE IODINE SPIKING IN BWR AND PWR COOLANT SYSTEMS W. F. Pasedag Nuclear Re;;ulatory Commission Office of Nuclese Reactor Regulation Division of Operating Reactors i
INTRODUCTION l
" Iodine spiking" is a term of convenience used to describe the temporary increase in the primary coolant iodine concentration frequently observed following significant power changes in BWR and PWR plants. The reported data shows this temporary ;ncrease in iodine concentrations to occur following shutdowns, start-apt, rapid power changes, and coolant depressurization.
Iodine spikes are characterized by a rapid increase in coolant concentration by as much as three orders of magnitude, followed by a return to pre-spike concentrations. The latter characteristic distinguishes the spiking phenomenon from a step-wise permanent incremsa in coolant activity level caused by the sudden failure of one or more fuel rods.
The occurrence of temporary increases in reactor water iodine concentrations particularly following shutdowns, has been a well established fact for many years. However, very little data has been reported and, to date, no single, eatirely satisfactory explanation of the phenomenon has been demonstrated.
l Notley and MacEwan observed a stepwise release of fission gases from UO2 fuel j
during power transients, and attribute this observation to the release of fission gases trapped in bubbles within the UO2 matrix. They observe that
"(fissien) gas appears to be released as the thermal power is decreased to zero during reactor shutdown." Carrol and Sissman2 measured fission gas releases from cooling UO2 and attribute the release to thermal stress arising from rapid cooling of the ceramic fuel. The release of trapped fission gas results from the opening of microcracks, and strain along grain boundaries 3
produced by the thermal stress. Eigenwillig and Hock suggest that shutdown l
spikes may be explained by water leaching of the inner surfaces e defective fuel rods. Following shutdown in BWR's and during power reductions in,PWR's water is assumed to penetrate the defective rods and leach out plated-ou iodine from the interior of the rod.
No attempt is made in this review to derive a model to describe the mechanism of the release of iodine from the fuel during a spike.
Instead the available information concerning iodine spiking behavior is reviewed for i
empirical correlation with normall.y observed plant operating parameters.
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SAFETY SIGNIFICANCE OF IODINE SPIKINC I
l The current interest in-the iodine spiking phenomenon arises from the recognition that it may have a significant effect on offsite thyroid doses resulting from postulated accidents involving the release of reactor coolant, such as a steam line or instrument line failure in the BWR, or a steam genera-tor tube failure in the PWR, If these accidents do not result in additional fuel failure, the radioactivity carried by the released reactor coolant becomes the primary source term in the assessment of the radiological conse-quences of the postulated accident. Any increase in the iodine concentration of the reactor coolant, therefore, will increase the resulting thyroid doses.
Because these accidents produce the conjitions most conducive to iodine spiking, i.e. rapid power reduction followed by system depressurization, a conservative accident analysis must include an account of the resulting iodine spike.
A second consideration is the possibility of an accidental release of primary coolant during a period of high coolant activity resulting from a spike produced by a previous power change.
It must be recognized, however, that the probability of this coincidence of a previously initiated iodine spike with an accident occurring at or near the time of peak coolant concentra-tion is significantly smaller than the probability of the accident alone, particularly for ' plants exhibiting infrequent spiking behavior.
i Estimates of the increase in the thyroid doses resulting from these two iodine spiking effects on coolant concentrations during certain postulated accidents have been derived previously." The results of these investigations I
showed that iodine spiking has a pronoun.ced effect on offsite thyroid doses for the BWR steam line failure, BWR instrument line break, and PWR tube rupture.
The BWR steam line failure is not affected by iodine spiking initiated by the scram and depressurization caused by the accident itself, since the coolant activity release is terminated within seconds upon closure of the steam line l
isolation valves. However, the coincidence of a previously initiated iodine spike with a steam line failure results in thyroid dose increases directly proportioned to the increase in coolant iodine concentration caused by the spike. The analysis of the instrument line failure and the steam generator tube failure indicate significant increases in the offsite doses from the iodine spike caused by the scram and depressurization as wr11 as from the previously initiated spike.
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It should be noted that the spiking release rate which was assumed in these calculations was a nominal value (i.e. an increase by a factor of 100 for 4 period of two hours). The data accumulated since that time shows that this rate has been exceeded repeatedly in operating plants, by as much as one order of magnitude. Similar ef fects are demonstrated for the use of a PWR steam line failure with large steam generator tube leaks by Fontecilla and Grimes in a paper presented at this conference.
In addition to these considerations, the effects of iodine spiking must be factored into the safety analyses of continuously (or very frequently) purged contain ments. Such containment concepts rely on fast-acting isolation dampers in the. containment ventilation system to prevent a significant release in case of a loss-of-coolant accident. Although this isolation may be achieved prior to any significant release of fission products from the damaged fuel, a release of primary coolant containing iodine at spike concentration prior to j
this isolation frequently represents a significant increase of the thyroid doses calculated for this accident.
'.'hese examples demonstrate the need for a method to predict, or at a minimum, to derive bounding values for the iodine spiking phenomenon.
In the following paragraphs, an attempt is made to examine all available data for such a bounding value.
t l
IODINE SPIKING DATA i
In 1972, in response to AEC concerns, GE submitted a topical reports docu-menting over twenty cases of iodine spiking at eight operating BWR plants.
Significant increase in reactor water iodine concentrations were observed following power changes, depressurization, and start-ups. Considerable varia-tion in spiking behavior was observed, not only among different plants, but also for individual plants. The authors noted, however, that there was a definite reproducibility of spikes in the same plant when the fuel status was the same.
l All of the GE data came from plants operating at relatively low fuel defect levels. An interesting and frequently made observation is that the ratio of peak spiking concentration to pre-spike reactor water concentration l
appears to be larger at lower fuel defect levels.
If one extrapolates this postulated trend, iodine spiking effects would become maaller as the normal l
l reactor coolant concentrations increase, and would eventually become insignifi-cant at large failed fuel levels. An enlargement of the data base to include all data reported to date, including several data poincs at higher fuel levels, however, does not bear out this conclusion.
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.I 6
Eickelpasch and Hock report measurements of concentrations during yearly shutdowns of the Gundremmingen BWR between 1970 and 1973. In all cases they observed spikes in the rate of activity release, after shutdown, with 131 I exhibiting the most pronounced spiking behavior. Considerable differences in the time of occurrence and the number of spikes were observed.
In all cases, however, the release rate coefficient for 1311, at its peak, was found to be about a factor of 100 larger than during power operation.
I Iodine spiking in PWR systems is reported in Westinghouse and Combustion 7
Engineering reports.
R. Lutz discusses 13 spiking sequences in five PWR's, and concludes that shutdown sequences can be separated into three distinct spikes, resulting from the power change (e.g. scram), the initial phase of pressure reduction, and final deprassurization.
8 Combustion Engineering reports fifteen data sets at several PWR's but.
considers the majority of this data proprietary information, thereby preventing its examination in this public forum.
In additi n to these topical reports individual data points are documented in several plant-specific reports.10 11 ell DISCUSSION OF DATA All of the above-referenced data, as well as several unpublished data points, are reproduced in a uniform format in Tables I and II, wherever the appropriate data was available. The entries in these tables are best explained by use of several examples.
First, consider the spiking behavior exhibited in Figure 1, which is t
I reproduced from refere'nce 5.
This figure shows a three peak spiking sequence which is typical of several spikes observed during planned shutdowns. For the purposes of this discussion, this sequence is considered to consist of a sequence of three individual spikes initiated by the reactor condition asso-ciated with a single shutdown.
The initiating events for each individual spike are concluded to have been a power reduction of approximately 40 percent, a further 60 percent power reduction to shutdown, and depressurization of the coolant system.
(The power changes indicated in Table I are expressed in percent of full power wherever possible. Because full power level is not provided in Figure 1, these entries reflect the assumption of full power prior to the first power reduction.)
i The " equilibrium" conditions listed in Table I represent the iodine concentrations during normal, full power operation, without any spikic~
contributions and represent the lowest concentrations at (or near) full power operation.
The " equilibrium" cleanup rate refers to the average cleanup rate prevailing at the time of (and leading up to) the equilibrium coolant concentra-tion.
tion was assumed to be the first data point on the graph, i.eFor the 0.0035 uci/ml.*
. approximately individual spike. Table II lists the initial and peak coolant concentrations for each The " spiking time" associated with these peaks is 6.25, 3.5, and 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, respectively, which corresponds to the time from the onset of a rapid concentration increase to the time of the peak.
slope following the peaks, in most cases, corresponds approximately to the The downward reduction achieved by the cleanup system and, therefore, has been neglected in this analysis.
The term " total release," as used in Tables I and II, therefore, reflects the integral of the iodine 131 appearance rate from the onset of the spike to the time of the peak.
of 7, 142, and 546 curies was calculated.For the three spikes shown in figure 1, a total relea therefore, a total of 695 curies were released.For the entire spiking sequence, It should be noted that spikes even for similar shutdown procedures at the same plant do not always follow the ascent from a very small to a large spike demonstrated in this exceple.
Similarly, a spiking sequence may consiat of a larger or smaller number of individual spikes.
The average release rate factors of Table II represent the ratio of the iodine 131 appearance rate, averaged for the spiking time, as defined above to the equilibrium release rate prior to the spike.
Maximum release rate factors were determined for spikes for which sufficiently frequent measurements were reported to determine release rates for periods shorter than the total spiking time.
In a11: cases, however, these shorter intervals consisted of periods of one hour or greater.
i the average release race factors are 7,148, and 815.For the spiking sequence shown in Fig I
The second spike in this sequence has an obvious maximum release rate factor of 314 between 2 00 and 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />.
equilibrium value between 0700 and 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br />.The third spike has a maximum relea From this great variation of the release rate factor from 7 to 1030 for this spiking sequence alone l
it is apparent that it will be difficult to characteri:e iodine spikes by their release rates.
senritive to the sampling frequency.It also demonstrates that this parameter is particula It must be expected that significant mcxima in this paramatc; are not identified for sampling intervals greater than two hours.
this category.
Unfortunately, the majority of the reported data falls into j
- Concentration data given per units volume were assumed to be measured at room temperature, so that 1 m1Nigm.
The " release rate" listed in Table I refers to the release of131 the fuel during non-spiking equilibrium operation and, based on the I from assu=ption of equilibrium, is obtained by the product of the clean-up rate and the " equilibrium" concentration.
i i
DATA CORRELATION The parameter describing iodine spiking which is most useful in safety and accident analyses is the release r. ate factor. An examination of the data, however, indicates that this parameter is not suitable for use in empirical model because of its fluctuations not only for different spikes but within a given spiking sequence itself, and the susceptibility of this parameter to the inaccuracies resulting from insufficient sampling frequency. An integrated variable involving many measurements may be expected to be less susceptible to inaccuracies in measuaement. Based on this reasoning the most reliable parameter to be extracted from this data appears to be the integ'al of the r
concentrations during each spiking sequence, i.e., the total curies released i
during the sequence.
A plot of this parameter versus the equilibrium release rate is shown a
Figure 2.
Although there is no single-valued correspondence between these variables, it is possible to draw a bounding line subtended by all spiking sequences. Thir boundary line indicates direct proportionality of the maximum observed release for any spiking sequence with the equilibrium release rate.
Only one data point falls above this line, i.e., the' plant A spiking sequence of 9/24/71. However, the deviation from direct proportionality is only 10 percent, which is well within the error band associated with this data.
The proportionality constant for this line is 10 Ci/(uci/sec), or 7
Q = 10 R,
where:
Q is the maximum release of 131I during a j
spiking sequence (pCi),
R is the equilibrium release rate observed prior to the spiking sequence (pCi/sec).
Realizing that the equilibrium release rate is an indicator (albeit a very cursory one) of the power generated in defective fuel rods, the direct proportionality of the envelope of all spiking sequences to this parageter j
suggest that there is a certain limited fraction of a defective rods inventory which is available for spiking. Therefore, as the number of failed rods l
increases, the inventory available for spiking increases in proportion to the I
equivalent failed fuel level, f
'i l
j f
In order to determine the fraction of the failed rod's inventory available for release in a spike, an accurate measure of the fuel failure level is equired. At present, not enough of the available iodine spiking data sets include the 131 /133I ratio, or other indicators, to permit an accurate 1
essessment of core conditions prior to the spike. If the equilibrium appearance rate is assumed to originate only from power-averaged failed rods eithout any contribution from recoil fission products, the maximum release line shown on 131I inventory of these Figure 4 represents about 12% of the saturation failed rods.
t A plot of the curies released during each individual spike vs. the 131 squilibrium 1 release rate is shown in Figure 3.
Although the release from each individual spike may be expected to be significantly less than the summation of the total release for a spiking sequence, Figure 3 shows that the largest single spikes observed are comparable to the sequence sums. The proportionality constant, therefore, is approximately 107 (sec 1) for individual spikes as well.
This observation, i.e. that the maximum release during a single spike is nearly the same as that for the multiple-spike sequence suggests that the
" spiking inventory" described above is independent of the method of release.
This conclusion, however, does not address the question of which spiking sequence, or what order of the initiating events elicits the maximum release.
The answer to this question requires further study of the spiking mechanisms.
CONCLUSION l
t The available iodine spiking data from both PWR and BWR plants was l
reviewed for possible correlation with operating plant parameters. It is concluded that the number, duration, and magnitude of spikes cannot be predicted i
131I release of 10 curies per pCi/sec l
without further study. However, a maximum l
of the equilibrium pre-spike iodine release rate from the fuel can be demonstrated for both BWR and PWR plants. This correlation suggests direct proportionality between a maximum inventory available for spiking and the failed fuel level of the core.
i l
REFERENCES 1.
M J.F. NOTLEY and J.R. MacEwan, Nuclear Applications, 2, 477 (1966) 2.
R.M. CARROL and 0.. Sissman, " Evaluating Fuel Behavior during Irrradiation by Fission Gas Release," ORNL-4601 (1970).
3.
G.G. EIGENWILLIG and R. HOCK, ANS Transactions., 23, 258 (1976) 4.
W.F. PASEDAG, ANS Transactions, 17, 336 (1973) 5.
J. BRUTSCHY, C.R. HILLS, N.R. HORTON, A.J. LEVINE, " Behavior of Iodine in Reactor Water During Plant Shutdown and Startup,"
NEDO-10585, General Electric Corp., San Jose, CA. (1972) 6.
N. EICKELPASCH and R. HOCK, " Fission Product Release After Reactor Shutdown", IAEA-SM-178/19, Proceedings From A Symposium, Vienna, Austria, October, 1973 7.
R.J. LUTZ, JR., " Iodine Behavior Under Transient Conditions in the Pressurized
- Water Reactor," WCAP-8637, Westinghouse Electric Corp.,
Pittsburgh, Pa. (1975) 8.
G.F. CARUTHERS and P.H. GREEN, " Iodine Spiking", CENPD-180, Combustion Engineering, Windsor, CT. (1975), Proprietary 9.
J. STEVENS, Yankee Atomic Co., Personal communication, 1974 10.
D.L. UHL, ed., P.J. GRANT, D.F. HALLMAN and A.J. KENNEDY, "Oconee Radiochemistry Survey Program Semiannual Report, January-June 1974",
l Babcock & Wilcox, Lynchburg, Va. (1975) 11.
J.E. CLINE, E.D. BAREFOOT," Study of Reactor Shutdown Radioactivity
' Spiking' at the Three Mile Island Nuclear Power Station During February 20-21, 1976", Science Applications, Inc. (1976) 12.
J.E. CLINE, " Study of the Point Beach PWR Secondary System and Shutdown Primary Spiking", Nuclear Environment Services 13.
Licensee Event Report R0-50-315/76-52, Indiana Michigan Power Co.
(1976) 14.
Licensee Event Report RD-50-315/76-52, Indiana Michigan Power Co.
(1977)
I
t TABLE I 2
1
)
IODINE SPIKING DATA - INITIAL CONDITIONS PLANT PRIMARY EQUIL.
EQUIL.
RELEASE PROBABLE DATA NAME DATE REF.
COOLANT CLEANUP I-131 CONC.
RATE INITIATING SET MASS (kg)
COEF(sec-8)
(uCi/gm)
(uC1/sec)
EVENT NO.
3 BWR PLANTS l
Plant A 6/27/70 5
1.48E+5
2.4E-4 1.3E-3 45
-25 % in 0.5 hr A-11 a
Depress.
A-12 Plant A 10/1/70 5
1.48E+5 2.4E-4 1.9E-3 47
-25 % in 0.5 hr A-21 Depress.
A-22 i
Plant A 5/2/71 5
1.48E+5 2.4E-4 3.5E-3 93
-40 % in 0.5 hr A-31
-60 % in 2 hr A-32 Depress.
A-33 Plant A 9/24/71-9/25 5 1.48E+5 2.4E-4 5.0E-4 17
-20 % in 1.75hr A-41 Depress.
A-42 Plant B 5/1/71 5
1.6E+5 2.5E-4 6.5E-3 260
-90 % in 1 hr B-11 Depress E-12 i
Plant B 6/6/7 5
1.6E+5 2.5E-4 6.5E-3 260
-75 % in 2 hr B-21 Depress.
B-22 Dresdn.2 9/29/71-9/30 5 2.43E+5 1.25E-4 2.3E-3 70
-40 % in 6 hr D-11 Depress.
D-12 i
Shutdown D-13 Dresdn.3 10/5/71' 5
2.43E+5 1.25E-4 1.5E-4 5
-100 %
D-21
-10/6 Depress.
D-22
-10/7 Repress.
D-23 Restart D-24
-10/9 Scram (?)
D-25 Power Increase D-26 I
Oyst.Cr. 9/17/71-9/18 5 1.94E+5 1.0E-4 4.3E-3 85 Unknown 0-11
-45 % in 2 hr 0-12
- a Depress.
0-13 4
h 1
i d
a TABLE I IODINE SPIKING DATA - INITIAL CONDITIONS
~
PLANT PRIMARY EQUIL.
EQUIL.
RELEASE PROBABLE DATA NAME DATE REF.
COOLANT CLEANUP I-131 CONC.
RATE INITIATING SET 4
HASS (kg)
C,0EF(sec )
(uCi/ga)
(uC1/sec)
EVENT NO.
9 Mile Pt. 9/17/71 5
1.95E+5 1.25E-4 2.6E-3 65
-50 % in 0.5 hr N-11 i
Depress.
N-12 M111st.1 8/6/71 5
1.74E+5 6.8E-5 1.6E-3
.19
-60 % in 3 hr H-ll Depress.
H-12 i
M111st.1 9/22/71-9/24 5 1.74E+5 1.lE-4 1.9E-3 36
-100 % in 2 'hr M-21 Depress.
H-22 Unknown H-23 M111st.1 9/28/71-9/29 5 1.76E+5 1.3E-4
- 1. ')E-3 43
+30 % in I hr if-31 Scram M-32 M111st.1 10/2/71 5
1.74E+5 1.36E-4 7
7
+30 % in 2 hr H-41 PWR PLANTS Cinna 2/26/11 7
1.2E+5 2.75E-5 1.0E-1 3640 Scram C-Il
-2/27 Depress.
C-12
-3/1 Depress.
C-13 Cinna 4/14/72 7
1.2E+5 2.75C-5 5.0E-1 2100 Scram-restrt-scram C-21 4/15-16 Depress.
C-22 4/17-18 Part.-repress.
C-23
-4/18 Part.-repress.
C-24 lladdam 4/15/71-4/18 7 2.42E5 2.86E-5
<3.5E-2
<242 Scram 11 - 1 1 Depress.
11 - 1 2 lladdam 6/9/72 7
2'.42E+5 3.4E-5 5.0E-1 4100
-100 % in I hr 11 - 2 1
-6/10 Depress.
11 - 2 2
-6/11 Part. repress.
11 - 2 3 Hihama 1/8/75 7
1.63E+5 1.86E-5 5.0E-2 151
- 100 % in 4 hr I-11
-1/9 Depress.
1-12 i
t t
l TABLE I IODINE SPIKING DATA - INITIAL CONDITIONS I
PLANT PRIMARY EQUIL.
EQUIL.
RELEASE PROBABLE DATA NAME DATE REF.
COOLANT CLEANUP I-131 CONC.
RATE INITIATING SET i
MASS (kg)
COEF(sec'8)
(uCi/ga)
(uCi/sec)
EVENT NO.
I Pt.Beachl 4/5/74-4/6 7 1.72E+5 1.28E-5 1.3E-1 287 Scram P-11
-4/7 Depress.
P-12
-4/8 Depress.
P-13 l
Pt. Beach 2 2/26/76 7
1.72E+5 2.77E-5 6.lE-3 30
-90 % in 2 hr F-21 San Onof. 10/2/70-10/3 7 1.97E+5 3.2E-5 7.4E-2(?) 467(?)
-100% in*24 hr S-11
-10/4 "
~
Depress.
S-12
-10/6 "
Depress.
S-13 l
-10/7 "
Depress.
S-14 1
San Onof.
12/26/71 7
1.97E+5 2.88E-5 2.3E-2(?)
139(7)
Depress.
S-21 Depress.
S-22 Maine Y.
4/5/74 8
2.38E+5 1.8E-5 3.0E-1 1285 Scram Y-11 i
Oconee 12/12/73-12/13 10 3.2E+5 2.7E-5 1.4E-1 680 Scram E-Il J
3 Mile Is. 2/21/76 11 2.3E+5 1.67E-5 7
94
-75 % in <1 hr T-11 Depress.
T-12 Cook 11/20/76-11/22 13 2.62E+5 1.8E-5 2.0E-2 95 Scram at 70%
C-11 l
Cook 12/23/76-12/24 14 2.62E+5 2.9E-5 1.5E-2 115
-90 %in 25 hr C-21 i
Depress.(7)
C-22 i
Depress.(?)
C-23 i
Depress.(?)
C-24 1
4
{
NOTES:
j
- 1. Indicated references do not always provide all data listed, and in several cases the j
entries in these tables reflect the author's interpretation.
I
- 2. Percentages in " Probable Initiating Event" column refer to escalation (+), or reduction (-)
of power in percent of full power.
i e
a l
i
t TABLE II IODINE SPIKING DATA - SPIKING BEHAVIOR DATh INITIAL PEAK AVG. CLEANUP SPIKING RELEASE RELEASE RELEASE SET CONC.
CONC.
DURING SPKE.
TIME RA?2 FACTR PER SPIKE FOR SEQ.
NO.
(uCi/ga)
(uCi/gm)
(sec71)
(hrs)
AVG./ MAX.
(C1)
(C1)
BWR PLANTS i
A-11 6.0E-1 1.2E-2 2.4E-4 6.0 6/-
5.7 d
A-12 5.6E-3 7.5E-2 1.14E-4 3.5 35 / -
19.6 25 A-21 1.4E-3 1.4E-1 2.4E-4 6.25 35 / -
36.
I A-22 4.7E-2 5.6E-1 1.2E-4 3.5 260 / 385 155.
193 4
A-31 3.5E-3 1.4E-2 1.9E-4 3.0 7/-
6.6 A-32 4.lE-3 8.0E-1
- 1. >J -4 4.0 148 / 314 142.
A-33 2.8E-1 3.9E O 2.8E-5 2.0 815 /1030 546.
695 4
A-41 9.0E-4 3.0E-1 1.9E-4 5.0 363 / -
79.
A-42 4.5E-2 1.8E-1 1.2E-4 0.7 1800 /1800 55.
134 B-ll 6.6E-3 6.0E-2 2.5E-4 0.4 34 / -
34.
1 B-12 3.4E-2 1.5E-1 1.2E-4 2.0 20 / -
37.
50 B-21 5.5E-3 5.0E-2 2.5E-4 0.4 24 / -
9.
B-22 2.8E-2 1.3E-1 1.2E-4 2.0 15 / -
27.
36 D-11 2.3E-3 2.7E-2 1.5E-4 1.0 31 / -
7.8 D-12 7.2E-3 2.6E-1 1.5E-4 1.0 415 / -
104.
D-13 1.5E-2 1.3E-1 1.15E-4 7.5 52 / 150 98.
210 i
D-21 1.5E-4 4.0E-4 1.2E-4 1
11 / -
0.2 l
D-22 1.9E-4 2.4E-2 1.6E-4 3.5 255 / -
- 16..
D-23 1.0E-3 1.2E-2 1.4E-4 3.0 86 / -
4.6 21 D-31 4.5E-4 2.2E-3 1.2E-4(?)
2.5 15 / -
0.7 D-32 6.8E-4 2.2E-33 1.2E-4(')
9.0 10 / -
1.7 i
D-33 6.lE-4 2.8E-3 1.3E-4 2.2 24 / -
1.0 3
0-11 4.3E-3 6.3E-2 1.0E-4 3.1 14 / -
13.6 0-12 5.8E-2 7.2F-1 1.0E-4 5.0 203 / 380 305.
0-13 2.lE-1 6.0E-1 1.1E-4 1.5 340 / -
155..
474
s TABLE II IODINE SPIKING DATA - SPIKING BEllAVIOR DATA INITIAL PEAK AVG. CLEANUP SPIKING RELEASE RELEASE RELEASE SET CONC.
CONC.
DURING SFKE.
TIME RATE FACTR PER SPIKE FOR SEQ.
NO.
(uCi/ga)
(uCi/gm)
(sec-1)
(hrs)
AVC./ MAX.
(C1)
(C1)
N-11 4.9E-3 1.5E-1 1.5E-4 3.9 53/ -
49 N-12 6.0E-2 4.0E-1 1.7E-4 12 153 300 H-11 1.6E-3 3.0E-3 6.8E-5 3
5.
1 H-12 3.0E-3 4.0E-1 6.8E-5 10 230/420 156 160 H-21 1.15E-3 3.9E-1 2.7E-4 2
600/ -
155 H-22 2.2E-2 2.8E-1 7.0E-5 4
87/120 70 H-23 3.2E-3 2.5E-1 7.0E-5 3
115/250 70 300 H-31 5.4E-3 1.9E-1 1.4E-4 5
117/290 90 H-32 3.3E-3 1.6E-1 1.9E-4 2
96/140 42 130 H-41 5.7E-4 5.8E-2 8 E-5 6
7 14 14 PWR PLANTS G-ll 9.0E-1 6.9E 0*
2.0E-5 24 8/ -
2440 G-12 5.9E O 1.8E+1 1.8E-5 14 22/ -
4100 G-13 8.7E-1 5.2E U*
1.4E-5 8
6/ -
600 7100 G-21 6.9E-1 1.8E+1 2.2E-5 6
83/130 3800 G-22 6.8E O 1.lE+1 1.25E-5 12 1570 G-23 1.3E O 5.5E 0*
1.2E-5 14.4 1100 G-24 1.7E O 7.5E 0*
1.25E-5 5
1240 7700 11 - 1 1 4.lE-2 3.0E 0*
1.2E-5 10 102/ -
890 11 - 1 2 2.2E O 3.0E,0*
2.35E-5 5
117/ -
408 1300 11 - 2 1 3.0E-2 6.5E-l*
3.4E-5 7.5 2/ -
236 11 - 2 2 4.4E-1 6.0E 0*
3.lE-5 11 15/ -
2480 11-23 3.5E O 1.2E+1*
3.2C-5 5.75 40/ -
Slaa 6100
I TABLE II l
IODINE SPIKING DATA - SPIKING EEHAVIOR l
DATA INITIAL PEAK AVG. CLEANUP SPIKING RELEASE RELEASE RELEASE i
SET CONC.
CONC.
DURING SPKE.
TIME RATE FACTR PER SPIKE FOR SEQ.
NO.
(uCi/gm)
(uCi/gm)
(sec-1)
(hrs)
AVG./ MAX.
(C1)
(C1)
I-11 5.0E-2 4.4E-1*
2.6E-5 5.17 30/50 84 I-12 3.lE-1 6.0E-1 1.9E-5 5.67 25/ -
77 160 P-11 1.3E-1 4.6E-l*
1.3E-5 8
9/ -
76 P-12 4.6E-2 2.0E O 1.3E-5 2.5 138/ -
357 P-13 6.7E-1 1.2E 0*
1.3E-5 1.4 73/ -
106 540 P-21 6.lE-3 5.3E-2 2.8E-5 1.0 89/ -
10 10 i
S-11 7.4E-2 8.5E-l*
3.2E-5 7
21/ -
244 S-12 2,,3E-1 1.05E 0*
2.4E-5 7.75 20/ -
246 S-13 2.8E-2 8.0E-1*
2.4E-5 5.2 22/ -
191 S-14 5.7E-1 1.02E O O
6.3 8/ -
87 778 S-21 2.3E-2 2.5E-l*
2.9E 5 3.2 36/ -
54 S-22 1.2E-1 2.35E 0*
2.lE-5 3.0 340/ -
478 532 Y-11 4.4E-1 1.55E+1 3.2E-5 6.5 100/ -
4400 4400 E-Il 1.5E-1 5.2E-1 1.4E-5(?)
4.25 14/ -
150 E-12 1.5E-1 4.3E-1 1.6E-5 2.0 20/26 100 250 T-11 2.4E-2 1.5E-1 1.7E-5 3.55 26/50 34 T-12 1.3E-1 1.8E-1 1.7E-5 4.0 16/20 21 55 C-11 2.0E-2 2.8E O 1.6E-5 24 110/450 870 870 C-21 1.2E-2 2.5E O 2.9E-5 1.0 1660/1660 687 C-22 8.3E-1 1.6E O 2.9E-5 1.0 560/560 235 C-23 1.5E O 1.8E O 2.9E-5 5.0 150/ -
306 C-24 1.4E O 1.8E 0 2.9E-5 2.0 50/ -
42 1270 NOTE:
Peak concentrations marked by (*) indicate values estimated by Westinghouse.(Ref. 7)
FIG.1 IODINE SPIKING SEQUENCE AT PLANT A (BWR)
(From Reference 5) 80 l
REACTOR PRESSURE 3
~
{ 80 x
s 5
1 E **
I 4o V
W RE ACTOR POWER g
g 10 0
,0a E
)
~
1 3=
10 3 1131 i
Ig2
~6 5
CLEAN UP FLOW
's=
m h
5
(
e2000 B
l 5 sa 1&3-0 0900 1500 2100 C300 0900 1500 W
5/2/71 7
4
$/3/71 3
l
,--..--n---
.-m+-
,,,,,.--w,,p-,-w, wg-c
._y---,,,_y-w.+.y y-,,,,.--,=,%,5,-y,w..,,,,.
,.,w.
e,._,
._,wy,-gyye-,,.p,,._,.------,.s.,-f_.,-y,-w-.,w-,w,.,,s-,,.my-.w,,
aiu.
TOTAL I-131 RELEASE DURING A SPIKING SEQUENCE 4~
10 i
A i
A A
i e
l A
3
$ 10 A
m A
un e
m A
A e
l d
cc A
e e
l 3
a e
e e
A A
e F
i 2
10 i
A l
A A
A e
l l
A A
eBWR S
A PWR o
i A
l A
I J
e 10 1
14 102 3
4 10 10 j
EQUILIBRlUM 131 1 RELEASE RATE {pci/sec) i i
i
1!j'
~
40 I
1 A"
A i
A A
Ag EK A
IP 3
S I
0 1
L A
A
)ce U
iA s
/
D iC J$
I A A A
A E
V A
- e e
T ID A
R N
AA k
E S
A A
A I
3 R 2
E 0
L E
A A
I 1
G.P o*
E R
1 I
1 F E 3
S e*
e 1
M A
g U
E I
L R
B E
I L
R I
- e U
Q A.
A A
1 E
3 1
0 1
1 I
L A
T A
e O
T A
1 4
2 o
0 a
0 l
1 1
g n$ag g" asoH l
ll.
llll
!l
!l i!
!!-i';-iiiI
- i{ {!]
$