ML20199F440
| ML20199F440 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/27/1986 |
| From: | Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8606240328 | |
| Download: ML20199F440 (18) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET 4
P.O. BOX 8699 PHILADELPHI A. PA.19101 (215)8414000 March 27, 1986 I
Docket No. 50-278 Dr. Thomas E.
Murley, Administrator Region I U.S. Nuclear Regulatory Commission
~
631 Park Avenue King of Prussia, PA 19406
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SUBJECT:
Special Report - Uncontrolled _ Liquid Effluent
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Release - Peach Bottom Atomic Power' Station - Unit 3 i
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REFERENCE:
Technical Specifications 3.8.B.4
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and 6.9.2 l
Dear Dr. Murley:
'~
' ' ~ ' ~ ~ ~ '
This Special Report is being submitted pursuant _ to the requirements of Peach Bottom Atomic Power Station Technical Speci fications 3.8. B.4 and 6.9. 2 and presents information _.
discussed at the Peach Bottom site with members of your staf f on February 21, 1986.
Philadelphia Electric Company'.(PECO), by telecon dated March 19, 1986 between W. M. Alden (PECO) and J.
E.
Beall of your staf f, requested an extension for.. submittal ofjthis report to obtain additional info rmation.
This extension was found acceptable to Mr. Beall.
Technical Speci fication _3.8. B.4 states:
"With liquid waste being discharged without-treatment prepare and submit to the Commission within 21 working days pursuant to Speci fication 6.9. 3 ( subsequently-redesignated as 6.9.2), a Special Report which includes the following information:
Explanation of why liquid radwaste F/as'being-disoharged a.
without treatment, identification of any ino equipment or subsystems and the rea'sisn7orf perable inoperability.
-- 7 ~. 7 Action taken to restore the inoperable,equihment to b.
operable status.
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Dr. Thomes E. Murley March 27, 1986 Page 2 c.
Action taken to prevent a recurrence.
Reactor shutdown is not required."
Technical Speci fication 6.9. 2 states :
"Special Reports shall be submitted to the Director of the appropriate Regional Office within the time period specified for each report Description of Event:
On February 16, 1986, Unit 3 was in the cold shutdown condition nearing completion of a refueling and maintenance outage.
In preparation for startup, the condensate system was operating in long path recirculation via the 3A condensate pump.
At approximately 1520 hours0.0176 days <br />0.422 hours <br />0.00251 weeks <br />5.7836e-4 months <br />, the reactor operator was replacing a faulty pen on the main condenser vacuum recorder at control room panel 30C07A.
The recorder was pulled out of the panel on a set of guide tracks and then replaced in the panel when the pen replacement was completed.
A ribbon cable connected to the back of the recorder shorted as the recorder was being replaced in the panel.
The short circuit caused fuse F190 in panel 30C07A to blow.
This fuse provides protection for eleven instruments on panel 30C07A, including hotwell level controllers LIC-3086 (fine control) and LIC-3087 (coarse control).
These latter devices control the position of the hotwell makeup and reject valves in order to maintain proper hotwell level.
The blown fuse removed power to the hotwell level controllers which caused the makeup valves to close and the reject valves'to open.
This valve arrangement allowed a portion of the 3A condensate pump discharge flow to be directed to the Unit 3 condensate storage tank (CST).
The operator did not notice that CST level was increasing and hotwell level was decreasing because the blown fuse had also failed the CST and hotwell level recorders (the recorders f ail as-i s ).
In approximately 10 minutes, the CST filled and overflowed out the CST vent into the CST moat.
Spray from the vent also contaminated some areas outside the moat.
At 1550 hours0.0179 days <br />0.431 hours <br />0.00256 weeks <br />5.89775e-4 months <br />, the reactor operator received a call indicating that the Unit 3 CST was overflowing.
The operator proceeded to the 30C07A panel, noticed that the 3A condensate pump motor amps had just started oscillating (an indication of pump cavitation) and immediately tripped the 3A condensate pump (1553 hours0.018 days <br />0.431 hours <br />0.00257 weeks <br />5.909165e-4 months <br />).
This action stopped the discharge out the CST vent.
J
I
's Dr. Thomas E.
Murley March 27, 1986 Page 3 Personnel dispatched to investigate discovered approxima';ely two feet of water in the CST moat and puddles of water outside the moat.
Over the next six hours, the water drained out of the moat through two holes in its base.
Each hole was approximately 5 feet in diameter and 3 feet deep, and contained several vertical pipes which penetrated the base of the moat.
The water drained through the fill material under the moat, entered a nearby sump located outside the mo at, and was then pumped to the river via the storm drains. provides the analysis results of water samples obtained from the storm drain piping at the R&R building.
Figure 2 shows the location of this sample point which is designated as "R&R Out f all".
It should be noted that the first four samples identified in Attachment 3 were dip samples obtained directly from the river at the storm sewer outlet.
Immediate Actions Taken:
A Spill Recovery Team, headed by the Plant Manager and the Superintendent - Plant Services, was immediately established following the event.
The team was responsible for determining total surface area contamination, roping of f and covering the contaminated areas, surveying, sampling, decontaminating, and obtaining dose assessments.
Plastic was placed over the contaminated area and sandbags were used to prevent rain from spreading the contamination.
A plastic tent was later erected over the contaminated area to facilitate decontamination.
Excess water was soaked up using a drying agent, which was subsequently stored in barrels onsite.
The contaminated area is being decont am inated.
A special vacuum device is being used as part of the decontamination ef fort on certain surfaces.
A sampling program was established to obtain storm sewer s amples.
Initial sampling frequency was once every hour.
This was reduced in steps to the present frequency of once every day.
Calculations were performed to determine the extent of the spill.
Based on these calculations, it is estimated that a maximum of 36,000 gallons of water spilled out of the CST.
Also, analysis results of CST water samples obtained prior to the spill indicate approximately 3N3 uci/cc activity concentration.
Based on a spill of 36,000 gallons and an activity concentration of 3N3 uci/cc, it is estimated that the maximum total activity released in the spill was 0.41 curies.
It is estimated that only a small percentage of the 0.41 curies was released to the river.
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EDr. Thomas E.
Murley March 27, 1986 Page 4 An external inspection of the CST was performed.
No damage to the CST was evident.
Also, calculations determined that the CST was not overpressurized as a result of this event.
The worn ribbon cable on the back of the condenser vacuum recorder and the failed fuse F190 were both replaced and the af fected instruments were returned to service.
An investigation was conducted to determine the cause of the holes in the moat.
The investigation revealed that in early February, 1984 the area around the pipes had been excavated in order to replace. defective heat tracing on the pipes.
Although the heat tracing was replaced and verified to be working properly, the heat tracing f ailure alarm would not reset.
Troubleshooting the heat trace control circuit was pursued by the Maintenance group and the Instrument Lab.
The holes were not refilled because it was not known_ exactly where the prob.lem existed.
The investigation moved to the heat trace control panel located inside the Recombiner Building, but further ef forts did not resolve the problem.
To complicate matters, the new Computerized History and Maintenance Planning System (CHAMPS) was being placed into service at the time and 'the original hard copy Maintenance Request Form (MRF) that had been used to control the heat trace work was cancelled during the system changeover because it was believed that the heat trace work was complete.
In January 1985, temporary insulation was placed around the pi pes, but the holes were not refilled and sealed because the installing the inst.ation did not realize that individuals 1
the moat was a barrier.
The holes remained in the moat and served as the release path during the CST overflow.
Further review of the activities and controls which resulted in permitting the holes in the moat barrier to remain for an extended period of time indicates that the present CHAMPS computer system provides an ef fective mechanism for tracking long-term tasks.
This system should remove the root cause associated with the f ailure to resurface the moat.
Significance of Release The CST overflow caused a 12,000 square foot area to become contaminated.
A list of the contaminated areas is provided in Attachment 1, and their location ~ is indicated on Figure 1. -
There was no evidence of airborne contamination throughout the event.
There was no evidence of the release _ from water samples obtained at Conowingo Dam, approximately 8 miles down river.
The release did not exceed technical' specification dose limits.
Dr. Thomas E. Murley March 27, 1986 Page 5 As described in Section'2.4.3.3 of the Updated Final Safety Analysis Report (UFSAR), a release of this type has already been analyzed.
Results of the study indicate that the sudden release of a total of 1.0 curie would produce no risk to the public.
This study is representative of the release that occurred as a result of the CST overflow.
It should also be noted that the total release was less than 50% of the level at which an Unusual Event would be declared.
Dose assessment for drinking water and fish ingestion is provided in.
Corrective Actions to Prevent Recurrence The sand / gravel mixture in the holes served as an excellent filter for the contaminated drainage; ther e for e, sand was scooped out of the holes until the activity detected in the sand in the holes decreased to less than 1000 counts per minute.
The removed sand filled 57 drums, which are stored onsite at this time.
The holes were backfilled, compa cted and resealed, thereby restoring the design condition of the moat.
This task was completed prior to Unit 3 startup which occurred on March 2, 1986.
Additional corrective actions taken or planned include:
(1)
Mechanical Engineering Division is reviewing the Peach Bottom CST moat design for potential improvements in accordance with current design criteria.
(2)
Electrical Engineering Division has been requested to review the f ailure mode and control circuit of the CST makeup and reject valves and to determine the feasibility of expanding the range between the CST high and low water level alarm setpoints.
The range is presently very narrow and it is dif ficult to maintain water level within the band due to the number of plant activities involving the CST.
(3)
A modi fication is being considered which would provide separate fuses for the eleven instruments on panel 30C07A that are protected by fuse F190.
(4)
Signs are being prepared for installation to indicate that the condensate storage tank, ref ueling water storage tank, and torus water storage tank moats are barriers to the release of l
liquid ef fluents and must not be breached without i
plant management approval.
The signs will be hung l
at the access points to each of the moats.
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Dr. Thomas E. Murley March 27, 1986 Page 6 (5)
Information concerning this event will be added to the Senior Licensed Operator and Reactor Oprator Requalification programs.
The added material will stress the importance of barriers such as tank moats, fire doors, and penetration seals.
(6)
United Engineers is presently performing a study for Philadelphia Electric Company to determine potential liquid ef fluent release paths to the environs.
If there are any questions, please do not hesitate to contact us.
Very truly yours, hV W.
T.
Ullrich Superintendent Nuclear Generation Division cc:
T.
P.
Johnson, NRC Resident Inspector 1
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Docket No. 50-278 CONTAMINATED AREAS 2
LOCATION AREA ( f t )
Blacktop Driveway 1125 Moat 2447 Gravel By Driveway 300 By Recombiner Bldg.
51 Trailers North 768 South 768 Concrete Walls South Moat 1268 Wes t Moat 2214 North Moat
-506 Eas t Moat 1087 Recombiner Bldg.
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.1 ISOMETRIC PROJECTION OF CST
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(LOOKING SOUTHEAST)
E Docket No. 50-278 Page 1.
Drinking Water and Fish Ingestion _ Dose Calculations This attachment describes the methodology used to calculate the dose to members of the general public resulting from the liquid effluent release.
The calculation methodology was obtained from USNRC Regulatory Guide 1.109.
The storm drain sample containing the highest concentrations of radionuclides was used to calculate the whole body and liver lifetime dose commitments.
Included in the sample result is a calculated Sr-90 concentration based on a Peach Bottom specific Cs-137/Sr-90 ratio.
Samples have been sent to an off-site laboratory for Sr-90 analysis.
Whole body and bone dose commitments from Sr-90 were calculated using a Sr-90 concentration based on the Cs-137 concentration identified in the storm drain sample.
When the actual Sr-90 analysis result is available, an evaluation of the dose resulting from the calculated Sr-90 concentration versus the dose resulting from the actual Sr-90 concentration will be performed.
The liquid effluent release was assumed to be 36000 gallons for a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> duration.
The following is an explanation of the Regulatory Guide 1.109 equations and release specific parameters used to calculate the whole body and liver lifetime dose commitments.
Storm Drain Sample Results 17-Feb-86 at 0230 Co-60 1.55 N6 uCi/cc Cs-134 9.43 N7 uCi/cc Cs-137 6.47 N7 uCi/cc Zn-65 2.8E NS uCi/cc Sr-90 6.47 N8 uCi/cc (1/10 Cs-137 conce'ntration)
~3.18 N5 uCi/cc total Total liquid volume released: 36000 gallons Release duration: 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />
Docket No. 50-278 Page 2.
The following is the drinking water calculation obtained from Regulatory Guide 1.109, Appendix A.
exp (-]i pl t )
4.09 X 10 Mp Uap
_Q D
R
=
(
apj F
i i
alpj R
is the total dose to organ j of individuals of age group apj a from all of the nuclides i in pathway p, in mrem; 5
12 3
4.09 x 10
= 10 pCi x Ft.
x day units conversion factor di-28.3L 86400 sec.
M P
is the mixing ratio (reciprocal of the dilution factor) at the point of exposure (or the point of withdrawal of drinking water or point of harvest of aquatic food),
dimensionless; U
ap is a usage factor that specifies the exposure time or intake rate for an individual of age group a associated with pathway p, kg/ day; L/ day from table E-5 of Regulatory Guide 1.109.
3 F
is the flow rate of the liquid effluent, in ft /sec; O
is the release rate of nuclide i, in Ci/ day i
D is the dose factor, specific to a given age group a, aipj radionuclide i, pathway p, and organ j, which can be used to calculate the radiation dose from an intake of a radionuclide, in mre'm/pCi, from table E-ll of Regulatory Guide 1.109.
-1 fh,
is the radioactive decay constant of nuclide i, in hr 1
L
)
Docket No. 50-278 Page 3.
t is the average transit time required for nuclides to reach p
the point of exposure.
For internal dose, t is the total p
time elapsed between release of the nuclides and ingestion of food or water, in hours; The following are tdue release specific values used in the Regulatory Guide 1.109, Appendix A equation:
1.0 - no credit taken for dilution M
=
p 3
36000 gals x 0.134 Ft.
x hr.
3 F
=
= 1.34 N1 Ft.
/sec 10 hrs.
gal.
3600 sec.
the Ci/ day of each radionuclide released in 36000 gallons O
=
i for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> Co-60 1.55 N6 uCi 36000 3785 cc Ci 24 hr.
x
= 5.07N4 Ci/-
x x
x ~6 day.
cc 10 hrs.
gal.
10 uCi day The Qi values in Ci/ day were calculated using the same method described above.
Their Qi values are as follow:
Co-60 5.07 N4 Ci/ day Cs-134 3.08 N4 Ci/ day Cs-137 2.12 N4 Ci/ day Zn-65 9.35 N3 Ci/ day Sr-90 2.12 N5 Ci/ day 4
1.04 N2 Ci/ day total i
Note: Total Curies released = 1.04 N 2 Ci 10 hrs.
day x
x
= 0.0043 Ci day 24 hrs.
l
Docket No. 50-278 Page 4.
The following is the method used to calculate the lifetime whole body and liver doses (bone for Sr-90) for drinking water ingestion:
Co-60 whole body 5
3 R = 4.09 10 pCi Ft. day 1.0 2 L/ day 5.07 N4 Ci 4.72 N6 mrem X
X X
X Ci-L-sec.
1.34 N1 Ft./sec day pCi x exp (0.693 0.0001 yrs.)
(
x
)
(5.27 yrs.
)
R = 1.46 N2 mrem Similar calculations were performed for all the radionuclides identified in the storm drain sample and the calculated Sr-90 concentration.
The whole body and liver doses for these radionuclides are as follow:
Whole body Liver Co-60 1.46 N2 mrem 8.80 N3 mrem Cs-134 2.00 N1 mrem 4.00.N1 mrem Cs-137 1.00 N1 mrem 2.00 N1 mrem k
Zn-65 4.00 N1 mrem 1.10 mrem 7.20 N1 mrem 1.71 mrem l
The whole body and bone doses for the calculated Sr-90 i
concentration are 2.40 N1 mrem and 1.10 mrem, respectively.
Adding the Sr-90 whole body dose to the whole body dose as a result of the storm drain sample identified radionuclides, the whole body dose is 1.34 mrem.
In these drinking water calculations, credit for dilution by the river flow was taken into account for the downstream water intakes.
The dilution factors used were calculated based on river flow and the results of tracer dye studies in the conowingo
Dockot No. 50-278 At tachment. 2 Page 5.
Pond performed in 1960.
(See PBAPS UFSAR Section 2.4.3.3).
The dilution factors used for determining the whole body and liver doses due to this liquid release, are based on a river flow of 25,000 CFS.
Actual river flow was approximately 28,000 CFS.
The dilution factors for the downstream intake structures are as follow Baltimore Water Intake: 84.6 Chester Water Intake:
93.0 Conowingo Tailrace:
42.8 The whole body and liver doses to the downstream intake structures are as follow:
Whole body Liver Baltimore Intake 0.01 mrem 0.02 mrem Chester Intake 0.01 mrem 0.02 mrem Conowingo Tailrace 0.02 mrem 0.04 mrem The additional whole body and bone doses based on calculated Sr-90 concentration are as follow:
Sr-90 Wholebody Sr-90 Bone Baltimore Intake 0.003 mrem 0.013 mrem Chester Intake 0.003 mrem 0.012 mrem Conowingo Tailrace 0.006 mrem 0.025 mrem The following is the Fish Ingestion calculation obtained from Regulatory Guide 1.109, Appendix A.
5 exp(-]ip t )
R 4.09 x 10 Uap Mp O
B D
apj =
i ip aipj F
i
Docket No. 50-278 Page 6.
All variables previously defined except:
B is the the equilibrium bioaccumulation factor for nuclides i ip in pathway p, expressed as the ratio of the concentration in biota (in pCi/kg) to the radionuclide concentration in water I
(in pCi/ liter), in liters /kg: From Reg. Guide 1.109 Table A-1.
The following is the method used to calculate the lifetime whole body and liver doses (bone for Sr-90) for fish ingestion:
i Co-60 Whole Body i
5 3
1 R = 4.09 10 pCi Ft. day 1.0 x 0.06 Kg/ day 5.07 N4 Ci 5 x 10 pCi-L x
x x
(
l Ci-L-sec.
1.34 N1 Ft. /sec day Kg pCi 4.72 N6 mrem exp (0.693 x 0.003 yr.)
x x
(
)
pCi (57f7 yrs.
)
R = 2.19 N2 mrem Similar calculations were performed for all the radionuclides identified in the storm drain sample and the calculated Sr-90 concentration.
The whole body and liver doses for these radionuclides are as follow:
Whole Body Liver Co-60 2.19 N2 mrem 1.30 N2 mrem Cs-134 1.40 P1 mrem 2.22 P1 mrem Cs-137 5.50 mrem 1.16 P1 mrem Zn-65 2.40 P1 mrem 6.84 P1 mrem 4.40 P1 mrem 1.00 P2 mrem 1
Docket No. 50-278 Page 7.
The Whole body and bone doses for the calculated Sr-90 concentration are 2.20 N1 mrem and 9.7 N1 mrem, respectively.
Adding the Sr-90 wholebody dose to the wholebody dose as a result of the storm drain sample identified radionuclides, the wholebody dose is 44.2 mrem.
In these Fish Ingestion calculations, no credit was taken for dilution due to river flow.
It is assumed that the fish are at the mouth of the discharge point.
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i Docket No. 50-278 Page 1 ANALYSIS RESULTS.0F WATER. SAMPLES OBTAINED'FROM'R&R'0UTFALL'
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BCtivity Isotopic Concentration in order of*
Data Time (uCi/ml)
Abundanco 16-Feb-86 19:00 MDA
- 2n - 65 20:50 MDA
- 17-Feb-86 00:10 MDA
- 21:20 MDA
- O2:30 3.17E-05 06:25 1.71E-06 07:20 1.92E-05 07:30 2.00E-05 08:50 1.57E-05 09:25 1.23E-05 09:55 1.39E-05' 10:25 1.24E-05 10:55 1.11E-05 11:55 1.22E-05 12:25 1.02E-05 12:55 9.33E-06 13:25 1.06E-05 13:55 8.24E-06 4
16:50 1.92E-06 21:00 3.06E-06 18-Feb-86 01:00 NDA 05:40 9.16E-Q7 09:00 6.85E-07 13:05
- MDA, 17:23 3.00E-07 21:20 9.85E-07 19-Feb-86 02:00 3.44E-07 10:10 2.30E-07 14:15 5.49E-07 18:00 MDA 22:00 3.75E-07 20-Feb-86 01:55 MDA 10:05 MDA 13:35 MDA 17:50 4.53E-07 22:15 MDA 21-Feb-86 01:30 4.00E-07 05:15 3.03E-07 09:40 MDA 13:35 3.26E-07 17:25 MDA 21:20 MDA 7-____
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Dscket No, 50-278
. Attach ent 3 Pugs 2 ANALYSIS RESULTS 0F. WATER. SAMPLES OBTAINED'FROM R&R OUTFALL gtivity Concentra ti on Date Time (uC1/ml) 22-Feb-96 01:30 MDA C5:15 MDA 09:15 MDA 13:10 MDA 13:30 MDA 17:15 MDA 21: 00 1.9aE-07 23-Feb-86 01:20 MDA 05:30 MDA 09:20 MDA 13:15 MDA 17:05 MDA 20:$$
MDA MDA - Readings were below the minimum detectable activity.
Indicates dip samples err neously obtained from river approximately fifteen feet upstream frem storm sewer outlet.
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y g, va LOCATION OF DRAIN. SYSTEM _
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SAMPLE POINTS f
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