ML20040E070
| ML20040E070 | |
| Person / Time | |
|---|---|
| Issue date: | 01/06/1982 |
| From: | Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Bradford P NRC COMMISSION (OCM) |
| References | |
| NUDOCS 8202030064 | |
| Download: ML20040E070 (25) | |
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t'Et:0RA!!DtN FD : Comissioner Bradford FROM:
Willian J. Dircks, Executive Director for Operations
SUBJECT:
110HITORIllG OF RADI0 ACTIVE RELEASES VI A STOR}1 DRAltlS In our renorandum of August 28, 1981 (E00-10774), concerning nonitoring of radioactive releases via stom drains, we noted our plan to review Licensee Evaluation Reports (LERs) to detemine the frequency of occurrence and the scope or naa,nitude of inadvertent and unnonitored releases. This menorandun describes the results of our review.
A computer printout was run of LERs for liquid radioactive releases of all types from 1969 to the present. Fron this printout, which contained alrost 300 separate itens, 20 reports were detemined to involve unnonitored radioactive releases (or potential releases) from in-plant sources to the environment via site (plant) stom drains.
A brief description and a sunnary or evaluation of each incident is a'ttached. Additionally, two other itecs, not covered by LERs, cane to our attention and were included in the revi ew.
If sensitive radioactive effluent nonitors had been in-place in plant stom drain systens in each Case, ar.d if Conditions had been ideal (i.e., no significant flow frcri other sources such as rainfall or groundwater seepage),
it is reasonable to expect that nonitors would have detected ten releases, that detection capability would have been narginal in six releases, and that six releases would have been below detection linit concentrations (several consisted largely of tritiun, which is not anenable to monitoring in stom drains or other release pathways). This sunnary does not include the 11111 stone and Monticello releases previously reported.
The largest release to a stom drain systen was the 3.2 curies of iodine-131 released at Oconee-1 in January 1977. As described in a renort frcn B. Grines, EE9/00R, to K. P. Goller, AD/ DOR. dated July 7,1977, the turbine building surp discharge niping had been aligned to discharge water to the oil collection basin during a stean generator leak test (plant was shutdown). !!omally, the stean generator would have been drained to the liquid radwaste systen and clean water used during the test. This tire, however, the procedure was re-vised and contu.inated residual coolant was used in the test. A leak in the
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hydrogen cooler qasket resulted in release of prinary coolant-contaninated f
water to the e,une.
The sump pumns discharnod the excess water to the oil
,G collection basin, u51ch in turn overflowed via the plant storn drains to the p-
h, '
k
, $g Commissioner Bradford Keowee River in an unnonitored discharge. The discharge was sufficient to cause the plant to exceed one-half the plant design objective releases in a calendar quarter and thus exceeded plant Technical Specification reporting requirem nts.
To our knowledge, this is the only release via plant storn drains which exceeded Technical Specification reporting requirerents.
In our menorandum of August 28,1981 (EDO-10774), we stated that it was our opinion that a blanket requirenent for _ monitoring of radioactivity releases in stom drains was unwarranted from a safety standpoint. Our follow-up review has not disclosed any infomation of sufficient substance to alter our original opinion.
(Signed) William 1.Dircks Willian J. Dircks, Executive Director for Operations
Contact:
H. R. Denton Attachnent:
Description and Sumnary of LER Incidents cc: Chairnan palladino Commissioner Gilinsky Commissioner Ahearne Commissioner Roberts L. Bickwit. OGC D. Rathbun. OGC S. Chilk, SECY F. Renick. OPE WJ r Ns
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FACILITY:
Arkansas-1 DOCKETN0(S).
50-313 EVENT DATE:
06/12/76 REPORT DATE:
06/14/76 LER NO.76-04T CONTROL N0.
015013 EVENT DESCRIPTION:
While filling the sodium thiosulfate tank, tank overflowed to ground, drainage reached storm drain, which empties into lake. Total activity involved calculated to be 0.262 Ci, in 9,500 gallons. Amount which reached lake was not specified.
SUMMARY
/ EVALUATION:
5 5
2.62 x 10 uC1-
, 2.62 x 10 = 7.3 x 10-3 uCi Concentration:
3 3
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9.5 x 10 gal x 3.8 x 10 ml/ gal 3.61 x 10 A concentration of 7.3 x 10-3 E of a typical fission / activation product mix would be detectable by a storm drain monitor.
It is not noted if water already present in the storm drain was available to further dilute the water.
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FACILITY:
Beaver Valley-1 DOCKET N0(S).
50-334 EVENT DATE:
07/25/77 REPORT DATE:
08/01/77 LER NO.77-04L CONTROL NO.
018835 EVENT DESCRIPTION:
3.4 Ci tritium Primary water storage tank overflowed. Approximately 9,000 gallons of water.
Portion of water entered storm drain and reached river.
(Amount / volume not specified) a.
SUMMARY
/ EVALUATION:
Tritium would not be detected by a storm drain monitor.
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d FACILITY:
Dresden-1 DOCKET N0(S).50-010 2
EVENT DATE:
02/13/75 REPORT DATE:
02/20/75 LER NO.75-01T CONTROL NO.
012000 i
EVENT DESCRIPTION:
Water was observed leaking from the demineralized water storage tank, due to a crack in a drain valve. Water was leaking into tbc storm drain system.
Total release not given. Concentration in liquid was stated to be 11.3 pCi/1 i
or 11.3 x 10-9 uCi/ml (1.13 x 10-8 uCi/ml).
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SUMMARY
/ EVALUATION:
-8 A concentration of 1 x 10 uCi/ml would not be detectable by a storm drain monitor.
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S F'CILITY:
Dresden-2 DOCKETN0(S).
50-237 A
EVENT DATE:
09/15/76 REPORT DATE:
10/14/76 LER N0.76-03L CONTROL NO.
016013 EVENT DESCRIPTION:
Contaminated demineralized water was found leaking from an underground line into the storm drain system. The line was isolated and repaired. Water in the storm drain analyzed; the total activity released was calculated to be 17.8 uCi. Concentration and volume were not given.
SUMMARY
/ EVALUATION:
There is not sufficient information to determine what the concentration in the storm drain was in this incident.
If assum.ed to be mixed in 1,000 gallons of water, concentration would have been about 5 x 10-6 uCi/ml, which would have been marginal for detection by a very sensitive storm drain monitor.
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FhCILITY:
Fitzpatrick-1 DOCKETN0(S).
50-333 EVENT DATE:
01/06/76 REPORT DATE:
01/14/76 LER NO.76-04T CONTROL NO.
013957 EVENT DESCRIPTION:
A leak from the auxiliary boiler oil separator tank was released to storm drain. Leak rate was 60 gallons per hour for about 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Total release 164 u curies ~in about 360 gallons of liquid before being diluted in the storm drain.
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SUMMARY
/ EVALUATION:
The auxiliary boiler feed pump packing leaked, with water reaching the floor l
drain. The floor drain drains to an oil separator tank, which in turn drains to the East storm sewer. The auxiliary boiler in a BWR uses turbine conden-sate which has passed through a demineralizer; however, same low-level activity is usually present, although this water is often considered " clean".
164
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' CONCENTRATION BEFORE DILUTION:
= 1.1 x 10 uCi/ml 0g Such a concentration would have been detectable by a storm drain monitor--if diluted 50:1, it would no longer be detectable.
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FhCILITY:
Haddam Neck (Connecticut Yankee)
DOCKET N0(S).
50-213 EVENT DATE:
11/01/73 REPORT DATE:
11/13/73 LER N0.73-02L CONTROL NO.
000550 EVENT DESCRIPTION:
Estimated 270 liters of water from refueling water storage tank leaked to stormdrain(sewer)whereitwasdilutedwgthanestimated6,000 gal / min 1.87 x 10 uCi tritium also released.
water flow before leaving site.
Radioactivity 1,930 uCi, not including tritium.
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SUMMARY
/ EVALUATION:
The water leaked from the diaphragm of a valve on the piping from the refueling water storage tank.
The leak fell on a black-topped area from which rainfall normally drains to the plant storm drain.
Leaky diaphragm was replaced If averageconcentrationofradioactivitywouldbeapproximately1.4x10fh the leak is assumed to have occurred uniformly over a one hour period, uCi/ml, which probably would not have been detected by a monitor on the storm drain discharge.
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FACILITY:
North Anna-1 DOCKETN0(S).
50-338 EVENT DATE:
02/28n9 REPORT DATE:
03/27/79 LER NO. 79-024/43L-0 CONTROL N0.
025768 li EVENT DESCRIPTION:
Unit 2 containment sump pumped out by temporary pump, drained to storm drain system. Although Unit 2 was not yet operational (prior to fuel load), the Unit 1 sampling purge header leaked by pressure relief to the Unit 2 volume control tank, from which it leaked to the Unit 2 sump. Sump water slightly radioactiye (concentration not specified). Total release calculated 3.11 x 103 uCi. No detectable activity found in storm drain samples.
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Sut@lARY/ EVALUATION:
Samples taken from the storm drain discharge, the discharge canal, and at site boundaries showed no detectable radioactivity.
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' FhCILITY:
Oconee-1 DOCKET N0(S).
50-269 EVENT-DATE:
01/19/77 REPORT DATE:
02/03/77 LER NO.
77-3 CONTROL NO.
017062
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EVENT DESCRIPTION:
1 During plant shutdown, a test for steam generator leakage resulted in leakage from the main generator hydrogen cooler gasket, contaminating several floors of the turbine building and dumped a large volume of water in the turbine building sump. During the test, the turbine sump was aligned ~to the oil collection basin (outdoor pond). The basin over flowed via the plant storm drain system to the Keowee River.
SUfG!ARY/ EVALUATION:
)
Estimated release was approximately 100,000 gallons, containing approximately 3.2 curies of iodine-131.
The approximate average concentration of radio-activity was 8 x 10-3 uCi/ml I-131. Such a concent.ation, if undiluted by i
other sources contributing to the storm drain flow, would have been readily detected by a storm drain monitor.
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4 FACILITY:
Oconee Unit 2 DOCKET N0(S).
50-270 7
EVENT DATE:
REPORT DATE:
05/30/80 LER N0.
CONTROL NO.
l EVENT DESCRIPTION:
During an integrated leak rate test, a large volume of water was discovered in the tendon gallery, an annular region outside the reactor building below ground level. Normally, such water would have been automatically pumped to the yard drains via pumps in the gallery sump, on the assumption the water would be in-leakage from external ground water. Some contamination was identified in the water (<< 1 MPC). The water apparently leaked from the Reactor Building / Auxiliary Building interface (or at least that portion of the water causing the radioactive contamination).
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SUMMARY
/ EVALUATION:
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Not an LER, apparently because no actual release occurred. Reported here as a potential discharge via storm drains.
i The activity level was not specified; however, activity was stated to be much less than MPC. Since typical activity to be expected in such a location wouldbesomethinglikeCs-g37,anMPCwouldbeabout2x10-5uCi/mland 1/10th MPC would be 2 x 10- uCi/ml--which would be only marginally detectable or perhaps undetectable by a storm drain monitor.
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FACILITY:-
Oyster Creek-1 DOCKETN0(S).
50-219 EVENT DATE:
04/28/78 REPORT DATE:
05/26/78 LFR NO. 78-006/032-0 CONTROL NO.
021453 EVENT DESCRIPTION:
Pipe on roof cracked, permitting contaminated water to drain from roof to yard storm drain system: undiluted water concentration 2.56 x 10-4 uCi/ml.
If flow was 100 gal / min, then circulating water dilution reduced activity to less than tech spec limit, total release calculated at 872 uCi.
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SUMMARY
/ EVALUATION:
-4 If undiluted, concentration of 2.6 x 10 uCi/ml would be readily detected:by a storm drain monitor.
Diluted >100:1, it would no longer be detectable.
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q F'CILITY:
Peach Bottom-2 DOCKETN0(S).
50-277 A
EVENT DATE:
03-31-81 REPORT DATE:
04/14/81 LER NO. 81-022/01T-0 CONTROL NO.
036694 i
EVENT DESCRIPTION:
i A " feed and bleed" operation involving cleaning of the drywell chilled-water system, was found to be draining to a " normal" waste drain and then to the storm drain system. About 625 gallons containing about 200 uCi (Na-24 and Cr-51) and diluted by circulating water flow reached the Susquehanna River.
Dilution was in excess of one million.
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SUMMARY
/ EVALUATION:
200 uCi =
200 uCi
-5 uCi
= 8.3 x 10 CONCENTRATION.
625 gal (625)(3.8 x 104) ml ml A storm drain monitor would have detected this concentration, prior to entering curculating water discharge and river.
Total release 200 uCi i
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FACILITY:
Peach Bottom-3 DOCKETN0(S).
50-278 EVENT DATE:
08/25/77 REPORT DATE:
09/08/77
'LER NO.77-04T CONTROL N0.
019067 EVENT DESCRIPTION:
Feedwater leak, evaporating and then condensing on ventilation duct and draining to a floor drain, discharging to storm drain system, resulted in discharge of about 1.5 uCi total activity. Maximum of 18 gallons at 6.2 times MPC.
Activity not identified.
SUMMARY
/ EVALUATION:
1 uC
-5 INITIAL CONCENTRATION:
= 2.3 x 10 uCi/ml g3 Such a concentration would be detectable by a storm drain monitor. However, any dilution > 5:1 would bring the concentration down to non-detectable levels -
18 gallons in a dry storm drain would be adsorbed in the soil of the drain - any 4
water present would dilute the activity below detection levels.
i FACILITY:
H. B. Robinson, Unit 2 DOCKET N0(S).
50-261 EVENT DATE:
04/10/73 REPORT DATE:
04/24/73 LER NO.73-02T CONTROL NO.
001042 1
EVENT DESCRIPTION:
An overflow from a refueling water storage tank escaped to the storm drain system. Volume and concentration were not given. Total discharge was reported as 23.5 millicuries of mixed fission and activation products and 19.5 milli-curies of tritium. Principal cause was given as operator error, compounded by the absence of a high-level or overflow alarm.
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SUMMARY
/ EVALUATION:
i If the volume is assumed to have been 1,000 gallons, the concentration would i
have been about 6 x 10-6 uCi/ml, which would have been marginal for detection I
by a storm drain monitor.
If further diluted by other drainage, the activity would have been undetectable.
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FACILITY:
H. B. Robinson, Unit 2 DOCKET N0(S).
50-261 EVENT DATE:
04/23/73 REPORT DATE:
05/01/73 i
LER NO.73-02L CONTROL N0.
- I EVENT DESCRIPTION:
1 An overflow of water from a refueling water storage tank escaped to the storm
- j drain system. The total release was reported to be 380 curies of tritium.
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SUMMARY
/ EVALUATION:
5 This event-is essentially a repeat of what happened on 04/10/73, again caused 3
j by operator error.
This release was principally tritium activity, which would not have been de b
tected by a radiation monitor on the storm drain effluent (nuclide information j
by telephone contact with plant through Project Manager W. Ross).
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FACILITY:
H. B. Robinson DOCKET N0(S). __ 50-261 EVENT DATE:
05/10/74 REPORT DATE:
06/21/74 LER N0.74-02T CONTROL NO. 010292/010117(05/16/74)
EVENT DESCRIPTION:
19.7 mci (gross) of radioactive liquid leaked from a steam generator to the storm drain system. Estimated 360 gallons total. Plant was in refueling shutdown (From Project Manager W. Ross:
19.7 mci of mixed fission and activa-tion products - principal nuclide 12.96 mci I-131).
SUMMARY
/ EVALUATION:
The Robinson plant does not have a turbine building, perse, only a structure which is not much more than a " pad".
Rain falling on such a structure is collected in floor drains and is drained to the plant storm drain system, which is not monitored.
In this case, a liquid leak from a steam generator got into the rain drain system.
CONCENTRATION:
= 1.4 x 10-2 u 1
1.4 x 10-2 uCi/ml would have been readily detected by a storm drain monitor, provided no other flow was present in the stor~ drain for dilution.
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San Onofre-1 DOCKETN0(S).
50-206 1
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EVENT DATE:
12/05/78 REPORT DATE:
'01/03/79 j
LER NO.78-014/03L-0 CONTROL NO.
023179 P
j EVENT DESCRIPTION:
l 40 uCi (unspecified nuclides) released to storm drain. Cause not clear-from i
LER description but related to hydrazine additive pump recirculation valve and stated to be personnel error.
Volume of water not specified, o
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SUMMARY
/EVALUATI0f{:
If the leak is assumed to have involved 100 gallons of weter, concentration would have been i
40 uCi
= 1.0 x 10~4 uCi/ml 5
3.8 x 10 ml i
If the activity was mixed fission products (assumed) the activity would have l
been detected by a storm drain monitor.
5 Water from storm drain goes to the circulating water discharge where it is
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highly diluted.
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FACILITY:
Surry-1 DOCKET N0(S).
50-280 EVENT DATE:
08/02/74 REPORT DATE:
08/21/74 l
LER NO.74-03T CONTROL NO.
010518 EVENT DESCRIPTION:
Temporary hose connection being used to transfer water failed at a clamp.
Leaked from primary-grade water pump house, to storm drains, then into James River. 150 gallons (maximum) escaped to river. Total activity 0.033 curies.
SUMMARY
/ EVALUATION:
Connection subsequently modified to withstand pump discharge head'(pressure).
4 4
3.3 x 10 uCi
,3.3 x 10 uCi = 5.0 x 10-2 uq.i.
Discharge Concentration:
3 5
150 gal x 1.8 x 10 ml/ gal 5.7 x 10 ml This concentration could have been detected by a storm drain monitor.
It is L
not noted, however, if the water was subsequently diluted in the storm drain.
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Current plant design would probably prevent such a leak from reaching the j
storm drain system.
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c FACILITY:
Surry-1 DOCKET N0(S).
50-280 EVENT DATE:
12/05/75 REPORT DATE:
12/16/75 LER NO.75-01T CONTROL NO. 013874/016093 EVENT DESCRIPTION:
Primary grade water tank 1 overflowed during pump-over from tank 18. Approximately 625 gallons flowed into storm drain system. 0.024 curies total.
CONCENTRATIONS: H-3 9.99 x 10-3 uCi/ml I-131 2 A x 10-5 uCi/ml Co-58 1.43 x 10-5 uCi/ml Not noted if liquids reached river.
SUMMARY
/ EVALUATION:
Personnel error - high level alarm apparently ignored by operator. Resulted in tank overflow. Tank not enclosed by dike or retention base as recommended in Reg. Guide (current guidance -- not in effect at time plant was built).
The noted concentrations were marginal for detection by a monitoring system such as could be used on a storm drain.
p FACILITY:
Surry-1 DOCKETN0(S).
50-280 EVENT DATE:
11/29/75 REPORT DATE:
12/09/75 l~
'LER NO.75-04T CONTROL NO.
016223 g.
EVENT DESCRIPTION:
l Approximately 1,000 gallons of primary coolant grade water, overflowed from the t
demineralized water makeup tank, entered yard and storm drain system. Total activity 0.21 curies (Co-60, Co-58, Mn-54). High level alarm actuated but filling not terminated promptly - leak visually observed by an operator on routine patrol.
It was not noted if contmainated water reached the river.
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SUMMARY
/ EVALUATION:
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0.21 Ci in 1,000 gallons represents a concentration of 5
5 2.1 x 10 uCi
,2.1 x 10 uCi = 5.5 x 10-2 uCi/ml 3
3 6
10 gal x 3.8 x 10 ml/ gal 3.8 x 10 ml
)
A concentration of 5.5 x 10-2 uCi/ml would be readily detected by a monitor on i
a storm drain system.
It is not noted, however, if the flow was diluted in the storm drain system, or if the water ever reached the drain discharge point, where
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such a monitor would be located.
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FACILITY:
Surry-1 DOCKET N0(S).
50-280 EVENT DATE:
09/23/81 REPORT DATE:
10/21/81 LER NO.81-054/032-0 CONTROL NO.
EVENT DESCRIPTION:
Pumps on a'uxiliary steam drain' receiver failed to prevent overflow of receiver.
Water backed-up through a roof vent, and was drained from the roof through the plant storm drain system. This release was contrary to plant Technical Speci-fication 3.11.A.4 and reportable under Technical Specification 6.6.2.b.(4).
Total activity released was estimated at 0.0583 Ci (activity not further identi-fied) and was stated to be 0.66% of the plant Technical Specification limit.
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SUKGRY/ EVALUATION:
Source of leak to receiver was repaired. The drain receiver pumps were replaced.
The volume of water released was not specified.
If assumed to be mixed in 1,000 gallons of water, the activity concentration would have been about 6 x 10-6 uCi/ml. The activity was not identified; if it is assumed to have 3
been Cs-137, the release would have been marginally detectable by a very i
sensitive monitor.
If the activity had been tritium or a beta-emitter such as Sr-90, the release would not have been detected by a storm drain monitor.
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FACILITY:
Vermont Yankee DOCKET N0(S).
50-271 EVENT DATE:
07/18/76 REPORT DATE:
08/06/76
' LER NO.76-04T CONTROL NO.
015576 EVENT DESCRIPTION:
f Overflow of condensate stcrage tank, to moat, then to fuel oil storage tank sump, resulted in leak of water to river, via storm drain system te.;i reiease 1.6 curies tritium.
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t SUt@tARY/ EVALUATION:
Two leakage paths existed from the CST moat (retention basin) to the storm drain.
The only radioactivity detected in samples was tritium. A storm drain monitor would not be sensitive to tritium in any concentration.
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1 FACILITY:
Zion 1/2 DOCKET N0(S). 50-295/304 1
l EVENT DATE:
REPORT DATE:
09/29/77 LER NO.
CONTROL NO.
l EVENT DESCRIPTION:-
i Information memorandum No. 6, V. Stello, DOR, to ONRR Division Directors 9/29/77.
Primary system water, after being treated to remove fission product and irradia-tion product radioactivity, was being recycled to the secondary coolant system.
Significant amounts of contaminated secondary fluids leaked from the condensate and feed systems to the turbine building floor drain system; this system was dischargedunmonitoredtoLakeMichigan,resultinginlow-levelconcengrations of tritium reaching the lake, with a total activity on the order of 10 Ci/yr.
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SUMMARY
/ EVALUATION:
'The memorandum indicated that the liquid release frora the turbine building floor drains was unmonitored. This is contrary to current design practice which requires turbine building drcins to be continuously monitored and to be periodically sampled and analyzed to determine such nuclides as tritium which are not amenable to monitoring. We note that the 1972 SER (p. 11-3) estimated a total station tritium i
release, via liquid discharges, of 2,000 Ci/yr.
Tritium releases are not amenable to detection by on-line monitoring systems.
This is because the emissive radiation is a low-energy Beta particle which will not penetrate detection device walls.
EDO /07 7tf
%eg'o UNITED STATE'S 8[h"vi h NUCLEAR REGULATORY COMMISSION E
W ASHINGTON, D. C. 20555 g'g 4
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AUG 2 81981 MEMORANDUM FOR: Commissioner Bradford FROM:
William J. Dircks, Executive Director for Operations
SUBJECT:
MONITORING OF RADIOACTIVE RELEASES VIA STORM DRAINS Northern States Power Company recently reported that an unmonitored release of radioactive water occurred on July 30, 1981, at the Monticello plant.
Based on this and similar occurrences at Millstone, Unit 1 (June 21,1981) and at the Japanese Tsuruga plant, you asked if there were technical reasons for not continuously monitoring these paths.
As pointed out in my memorandum of July 14, 1981, concerning the Millstone release, the requirements of NRR are that during nomal reactor operation, including anticipated operational occurrences, all major and potentially significant paths for release of radioactive material should be monitored (10 CFR 50, Appendix A, General Design Criterion 64; Regulatory Guide 1.21, Position C.2). Plants are designed and reviewed, and Technical Specifications are provided, to assure that during nomal operation and anticipated opera-tional occurrences, all such release paths are monitored.
At Monticello, an unreviewed and improper action by a plant engineer resulted in radioactive water being eit. ployed in the cement solidification of radioactive resin waste at a newly-installed portable solidification system located in the radwaste shipping building. This building has no floor drains or curbs to pre-
.- vent water from escaping.
The building had not been designed for the type of l
use which was made of it by addition of the solidification system; the defi-ciency is being corrected by the licensee. The proposal for installation of the system had been reviewed by plant management and had called for the use of
" deionized water" for mixing with resin and cement so as to provide control of the pH of the mixture; the. responsible engineer improperly and inadvertently used slightly radioactive water from the reactor's condensate storage tank.
A rubber hose used to supply the water, secured by means of a hose clamp to the piping of the concrete mixing system, came loose, pemitting n estimated 2,000 gallons of radioactive water to spill onto the concrete f1r 3r of the radwaste storage building. The water ran down the sloping floor, under two closed overhead garage-type doors, and into the stom drain sy It is estimated thag 100 gallons of water, contaminated to 4.5 x 10 ytem.
uCi/ml of I-131 and 1.4 x 10- uCi/ml of I-133, entered the Mississippi River at the stom l
drain outfall, with the remainder of the water entering the soil or being l
trapped in the storm drain ditches. The release concentrations totaled ap-proximately 300% of maximum pemissible concentration (MPC, per 10 CFR 20, Appendix B, Table II, Column 2) at the point of release; dilution and disper-sion in the Mississippi River are assumed to have resulted in essentially instantaneous reduction to non-detectable concentrations with essentially zero environmental radiation dose impact.
DuPG oM g IQk?2.@DO8 6
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Connissioner Bradford While there are no insumountable technical reasons why storn drains could not be monitored for radioactive naterial, there are practical difficulties in the automatic sanpling or extraction of material for radioactivity analysis fran highly variable strean flow rates that would have to be resolved, and there are practical considerations involved in the volumetric neasurement of highly variable water flows in stom drain systens, if the total release is to be cuantifi ed.
Based on the assumption that each nuclear power plant is serviced by a single stom drain systen (also called " yard drains") we estinate the initial cost of installation per plant to be approx.inately 200 to 500 thousand dollars and that annual operation and maintenance costs would be approxinately 20 to 50 thousand dollars.
^
In light of our general knowledge of past experience with this type of unnoni-tored release from U.S. reactor operations, and the snall potential effect on public health which has resulted from such releases, it is our opinion that a blanket requirement for such monitoring is unwarranted from a safety standpoint.
We plan to confirm our current understanding of the nagnitude of this type of problen by reviewing LERs for the past five years to detemine the frequency, and the scope or nagnitude of such inadvertant releases.
In a related area, we have an ongoing study of portable radwaste solidification systers being con-ducted by a contractor to identify potential. problems such as that which led to the toonticello release. We will keep the Connission infome) of any new in-fomation developed by these studies which changes our view as to the need for nonitoring stom drains.
(S! nd) YMinU. Di.-Q Willian J. Dircks, Executive Director for Operations
Contact:
P. G. Stoddart Ext. 27682 cc:
Chairnan Palladino Connissioner Gilinsky l
Commissioner Ahearne Commissioner Roberts l
L. Bickwit, OGC D. P.athbun, 0GC S. Chilk, SECY F. Renick, OPE EDO s
- SEE PREVIOUS WHITE FOR C0fiCURREttCES n
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Connissioner Bradford DISTRIEUTIOM:
Central File OGC LP.C PDR OISE (3)
LPDR ACRS (10)
TERA SCavanaugh (ED0-10774)
HSIC DHottinghan WDircks ETSB Reading File HDenton ETSB Subject File 5.2 ECase TRehn D. Eisenhut VStel'l o JShea KCornell
.HSpith SHanauer 0 ELD TMurley Pfiattson RYo11ner KEccleston BSnyder TIppoli to PPAS TUovak HShapar SECY RDeYoung TShediosky ED0 10774 P. Kernig EJordan HThornburg RPangart PStoddart LHi ggenbothan EDiackwood
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ACTION CONTROL DATES CONTROL NO.
Qomm. Bradford COMPL DE ADUNE 8 27 8]
]Q774 AC K NOWLF C GME N T DATE OF DOCUMENT INTERIM REPLY 8.)Q.8)
TO:
PREPARE FOR SIGNATURE l
DirCks FIN AL REPLY FILE LOCATION O EXECUTIVE DIRECTOR OTHE R:
DESCRIPTION O LETTER 3 MEMO O REPORT Q OTHEF SPECIAL INSTRUCTIONS OR REMARKS Asks if there are technical reasons for not Continuously monitoring paths of liquid releases VIA via unmonitored storm sewers l
CLASSIFIEO DATA 1
DOCUMENT / COPY NO CL ASSlF IC ATIONl NUS.1BE R OF P AGES C ATEGORY POf7 REGIST RY NO.
O uSi O Ro O fro AGSIGNED TO:
DATE INFORMATION ROUTING LEGAL REVIEW O FINAL O COPv 1
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8 12 8]
DirCks ASSIGNED TO:
DATE NO LEGAL OBJECTIONS NOTIFY:
(n 4 A,
C ell O EoO ADMIN & CORRES BR g
- Dentor, COMMENTS, NOTIFY:
Shapar e x T.
NRC OR W EXECUTIVE DIRECTOR FOR OPERATIONS DO NOT REMOVE S COPY PRINCIPAL CORRESPONDENCE CONTROL C
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o UNITED STATES
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NUCLEAR REGULATORY COMMISSION gg
,s WASHIN GTON. D.C. 20$55 g
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b August 10, 1981 0FFICE OF THE 4
COMMIS$10NER 1
f i
I MEMO T0: William J. Dircks Executive Director for Operations
}?/3 FROM:
Peter A. Bradford
SUBJECT:
LIQUID RELEASES VIA UNMONITORED STORM SEWER (PNO-III-81-67)
This PN0 involves another radioactive liquid discharge via an unmonitored storm drain.
Are there technical reasons for not continu-ously monitoring these paths since the experiences at the Millstone, Monticello and Tsurga reactors seem to indicate that we should?
cc:
Chairman Palladino Commissioner Gilinsky Commissioner Ahearna Commissioner Roberts Samuel J. Chilk Dennis Rathbun Leonard Bickwit yiel (;h f,?
g9
(. l 0 *
- O Rec'd Qtf. EDO Date. *Y-/ t-6 l L-
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7
/
...m PRELIMINARY NOTITICATION July 31. 1981 Date:
PRELIMINARY NOTIT'1CATIQN OF EVENT OR UNUSUAL.0l:CURRENCE--PXO-III 67 ' *;.
- i This prelleinerv 5otification constitutes EAREN not. ice of events of POSSIELE Y..,,
t safety or public interest sinnificance.
The infor=ation presented is as
~
Eitially received without verificatien or eva1u's' tion and is bacically all.
that ic E.covn by IE staf f as of this date.,
.:.-Jye;---
.FAtlCITY:
Northern States Pnwer Company
.".cnticello Nuclear Generating Plant Docket No. 50-263
SUBJECT:
UNPLANNED L1 QUID REl. EASE,'9
.;p.-
'~.'2.,*.--
A small. unplanned, liquid release (slightly; exceeding technical specification t
limits) occurred at approximately 10:00'p.m.~ (CDT) on. July.30,i ISBl.
The liquid was releeded f rom the condensate storage tank when a-temporary hose connection i.
,. broke inside the radwaste building....,The. water...ran out; of.the 'radwestt building an.d in.to a storm sewer.
a.The licensee estimates that about 2,000. gallonst were released, most of which was >.
.s- :-
absorbed in the ground before reaching' the storm'sewe,r, and that 'about 100 s'
1;allons was discharged into the river..The licensee has-diked the storm sewer and is in the process of recovering the remaining water.
~O Semples teken in the storm sewer showed 4.2 E-7 'uti/mi' t-131 and 1.4. E-6 uCI/ml l-133,;which c.xceed tbc technical specification limits' for these nuclides.
-(I-131 MPC is 3E-7 uti/ml; l-133 HPC is lE-6 uCl/mi.) :. River dilution would.-
i reducc the concentrations to below MPC within several& yards of the storm sewer i
outlet.
.The licensee issued c. press release at 8:00 a.m. t (CDT)..and is. planning a. press j
briefing at 11:00 a.m.
(CDT).
There has been'significant local news media interest.
4 No press release is planned by Region lit (Chicago) atethis time; Region ill is responding to news media inquiries.
t The State of Minne'sota and the EPA have been notified.
The Reildent inspectors are reviewing licensee actions onsite with support by telephone from a Regional Radiation Specialist.
Region ~;ill received notification of this. event by telephene f rom the NRC t.'atch u.
Officer et 10:45 p.m. (EDT) on 7/30/61.j This information is current cs of j
10:30 a.m., July 31, 1981.
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CONTAC,T:
P. C. Lovendalc L. ~ R. Greger < -
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384-2638 384-2644.
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