ML19344B180
| ML19344B180 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/21/1980 |
| From: | NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML19344B177 | List: |
| References | |
| NUDOCS 8008250709 | |
| Download: ML19344B180 (13) | |
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EXHIBIT A PRAIRIE ISLAND hTCLEAR GENERATING PLANT DOCKET hTMBERS 50-2S2 and 50-306 LICENSE AMENDMENT REQUEST DATED AUGUST 21, I?30 PROPOSED CHANGE TO ENVIR0hENTAL TECHNICAL SPECIFICATIONS APPENDIX 3 0F OPERATING LICENSE DPR-42 and DPR-60 Pursuant to 10CFR50.59, the holders of Operating License DPR-42 and DPR-60 hereby propose the following change to the Appendix 3 Technical Specifications:
Specification 3-2.4.1 Chlorine PROPOSED CHANGE Change the requirements to allow special chlorination programs according to the attached Exhibir. 3.
REASON FOR CHANGE The detrimental organisms (produces primary ascebic ceningoencephlitis in san) are present in the plant circulating water system. Chlorination prior to human contact via plant cleaning operations will remove the occupational health ceacern according to medical advice.
ENVIRONMENTAL EVALUATION In the prior request for the license a=endment, dated October 30, 1979, we re-quested permission to chlorinate the circulating water system twice in a calendar year, but the authorization granted only a single chlorination.
The need
,r this chlorination exists periodically each ti=e equip =ent cleaning operat.ans require possible hu=an contact with these organis=s.
Consistent with NSP environ = ental policy, the satter is fully coordinated with the Minnesota Pollution Control Agency (MPCA), the issuing agency for NPDES pe rmi t s. The chlorination programs are conducted under authorication by the MPCA and a report on the results is furnished to the agency.
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EXHIBIT.B.
4 LICENSE AMENDMENT REQUEST DATED AUGUST 21, 1980 i
Exhibit.B, attached, consists of a revised page B-6 of the Appendix B Technical Specifications incorporating the proposed change.
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B-6 Specification:
The cooling water system shall be chlorinated for not more than a total of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day.
During chlorination periods, the total residual chlorine concentration at the outfall of the circulating water system shall not exceed 0.05 ppm.
If chlorine treatment of the cooling water system is 30 minutes or less per day, the total residual chlorine concentration at the outfall shall not exceed 0.1 ppm.
Correc-tive action will be taken if the protection condition is exceeded.
If chlorination of other systems is necessary, the same standards apply.*
Basis: The circulating water system condensers are cleaned mechanically.
Normally only the cooling water system is chlorinated. The protection conditions of this specification will provide protection of the aquatic biota in the receiving waters.
2.4.2 Corrosion Inhibitors and pH Control Agents Objective: To avoid a significant deterioration in the river's water quality, by limiting the discharge of certain chemicals from the plant.
Specification: The amount of certain chemicals discharged to the river shall not exceed the following cumulative annual amounts as follows:
ammonia 3,300 lb/yr.
hydrazine 2,800 lb/yr.
morpholine-700 lb/yr.
cyclohexylamine These chemicals are discharged at the outfall. No other corrosion inhibitors shall be discharged. While remaining within the above annual limits, da.ly blowdown discharge may vary as operations require, but unde c no conditions exceed a maximum of 30 pounds per day of ammonia at the outfall, with proportionately lower amounts of the other chemicals specified above.
If the stated daily or annual protection conditions are exceeded, corrective action will be taken.
Basis: The only release of corrosion-inhibitor chemicals in plant operation is from the all volatile water chemistry treatment (AVT) required for the steam generator secondary water treatement system.
During normal full power operation, the steam generator blowdown flow is normally maintained at 120 gpm (total for both units).
- Special chlorination programs for the circulating water system, similar to that described in Exhibit C of the License Amendment Request dated August 21, 1980 are permissible up to twice in each calendar year.
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1 EXHIBIT C NORTHERN 5TATES POWER COMPANY u i ~ ~ c..o u.. u ~ ~ e.ov4...oi October 25, 1979 T K Senerkenbach, Chief Compliance and Enforcement Section Division of Water Cuality Minnesota Pollution Control Agency Roseville, Minnesota 55113 ATTENTION:
D L KRIENS PRAIRIE ISLAND NUCLEAR GENEPATING I'IANT Chlorination Plan to Treat Circulating Water As you are aware, the parasitic amoeba, Naeolaria fowleri has been identified in samples taken from the Prairie Island Plant Circulating Water System.
NSP became aware of the existence of N.
fowleri on September 25, 1979.
The Minnesota Department of Health was notified of the presence of the amoeba on Septem-ber 25.
A meeting was held with MDH on September 26.
The concensus of Health Department personnel was that the existence of the amoeba did not present a public health threat, nor was there any past record of health proble=s in Minnesota related to this organism.
Howeve r, the a=ceba's presence does present an occupational health concern.
As a precaution, on Septechar 26, plant personnel were instructed to wear rubber gloves when touching plant circulating er cooling water and wear respirators when working in the area cf the cooling tower.
l Subsequently, the Minnesota Department of Natural Resources and l
the Minnesota Pollution Control Agency were advised of the pres-ence of the organism and a plan to treat the circulating water j
system to destroy the organism was developed.
The purpose of this letter is to provide specific details of our proposed treat-I l
ment and secure MPCA approvsl for an alteration in vne =cde of operation and the addition of chemicals to the Prairie Island Circulating water System.
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NORTHERN CTATE'3 POWER COMPANY Page 2 P I Chlorination blan MPCA - Oct 25, 1979 Literature references and recommendations by Dr Richard Tyndall of the University of Tennessee indicate that exposure to chlorine at'a concentration of 2 mg/l (measured as free chlorine) for a period of six hours should be effective to destroy both the amoeba and its encysted form.
In summary, our tre:tment plan consists of two phases:
Phase One will occur during helper cycle operation and will be limited to chlorination of the cooling towers with subsequent dechlorination prior to discharge; Phase Two will occur during closed cycle operation with chlor-ination of the circulating water system for six hours at 2 mg/l free chlorine with dechlorination prior to discharge.
This two-phased treatment procedure has been selected to prevent large amounts of biological material from entering the plant intake water systems.
Since the amount of material which may be removed from the cooling towers due to chlorination is unknown, it is desirable to avoid its introduction to the intake.
To aid in the effectiveness of chlorination, a biodispersant will also be utilized.
The product chosen, Nalco 7348, is presently being used in the cooling water system at Prairie Island with approval of the MPCA.
Once the plant returns to normal operation, followup sampling for E. fowleri will confirm the effectiveness of the treatment.
Our present schedule calls for initiation of the treatment program on Wednesday, October 31, 1979.
DETAILS OF TREATMENT PROCEDURE:
A)
Phase One - Helper Cycle 1.
Operational Parameters e
Unit 1 on line o
Unit 2 on lin; e
Discharge gates open e
Recycle gates closed p
All cooling towers in service with maximum practical number of fans on-y.._,..
NORTHERN CTATEC3 POWER COMPANY
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Page 3 P I Chlorination Plan MPCA - Oct 25, 1979 The transition from present (normal) operation to helper cycle requires a gradual reduction in recirculation canal temperature to prevent cold shock to resident fish.
For temperatures between 400 F and 600 F, a 50 F drop per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is allowed.
Thus, for the anticipated AT of about 150 F, three days will be required to reach helper cycle operation.
2.
Fish Removal Since chlorine at concentrations of 2 mg/l (free) are likely to be lethal to fish, attempts will be made to remove fish from the cooling tower return canal prior to commencement of chlorination.
NSP biologists will coordinate their efforts in this regard with MDNR personnel.
We are presently planning to add copper sulfate at a concentration of 0.3 mg/1.
Fish in the canal will sense the copper sulfate and actively seek areas free from the chemical.
Thus it is felt they will leave the canal via the discharge structure.
The application of (.epper sulfate will be conducted in con-junction with MDh?. personnel.
3.
Chlorination e
Chlorination chemical:
liquid sodium hypochlorite (15% sodium hypochlorite) l Chlorination injection point:
Cooling tower pump bay e
t Chlorination injection method:
pumped from truck e
l tanker at known pumping rates l
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Biodispersant:
Nalco 7348 l
l Biodispersant injection point:
cooling tower pump bay e
l Biodispersant injection method:
pumped from 55 gallon e
l drums at known pumping rates I
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NORTHERN CTATED POWER COMPANY
,a Page 4 P I Chlorination Plan MPCA - Oct 25, 1979 The volume of water in the cooling towers and cooling tower return canal is about 21.5 million gallons.
At a flow of 600,000 gallons per minute, the time through the system is 36 minutes.
Thus, chlorination during Phase One will have a contact time of 36 minutes.
Recent Jf.b tests of Mississippi River water indicate a 36 minute
~.alorine demand of 5.5 mg/1.
To maintain 2 mg/l free chlorine, a dose of 7.5 mg/l will be required.
- However, the tests were not able to determine the additional chlorine demand of the circulating water system due to the presence of slime in the cooling towers, sediment in the canals, etc.
Thus, the dose of chlorine required will be greater than 7.5 mg/1.
Monitoring of the free chlorine concentration in the system will dictate what additional chlorine will be required.
4.
Monitoring e
Sample point location 1)
Cooling tower pump discharge - Sample Point 1 2)
Cooling tower return canal - Scmple Point 2 3)
Discharge canal - Sample Point 3 e
Chlorine Measurement Test Methods 1)
Iodometric titration utilizing amperometric end point l
l 2)
DPD colorimetric r
e Monitoring Frequency 1)
Grab samples from Points 1 and 2 will be taken at 30 minute intervals I
t 2)
Grab samples from Point 3 will be taken at 30 minute intervals.
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NORTHERN CTATED POWER COMPANY Page 5 P 1 Chlorination Plan MPCA - Oct 25, 1979 Sample Point 1 was selected to provide information on the maximum chlorine concentration in the system.
This point is located immediately-downstream from the chlorine application point, yet upstream of the cooling towers where the greatest chlorine demand is expected.
Sample Point 2 is located at the cooling tower return canal at a point downstream of the discharge from the last cooling tower.
Point 3 is the normal discharge canal sample Point.
Point 2 will dictate additional requirements to add chlorine and also provide information to determine the amount of dechlorination required.
Both amperometric titration and DPD colorimetric pro-cedures will be utilized.
The monitoring frequency indicated above will be the minimum amount of monitoring.
Additional testing at these and other points is likely.
5.
Dechlorination e
Dechlorination chemical:
Liquid sodium sulfite o
Dechlorination injection point:
cooling tower return canal e
Dechlorination injection method:
pumped from truck tanker at known pumping rates The dechlorination will commence with the start of chlorination.
Sodium sulfite will be added on stoichio-metric basis with the total chlorine residual.
The dechlorination will continue at a rate proportionate to the chlorine concentration at Sample Point 2.
Concurrent analysis for chlorine at Point 3 will indicate the effectiveness of dechlorination.
NORTHERN GTATED POWER COMPANY
,e Page 6 P I Chlorination Plan MPCA - Oct 25, 1979 6.
Cessation of Phase One The purpose of Phase One treatment is to prevent large amounts of biological material sluffed off the cooling towers from entering the plant intake systems.
Since it is impossible to predict the amount of material the chlorination will remove, the length of time for Phase One cannot be stated in advance.
It is anticipated that three to four hours should be sufficient.
B)
Phase Twc - Closed Cycle 1.
Operational Parameters e
Unit 1 - on line at reduced load e
Unit 2 - on line at reduced load e
Discharge gate open to allow approximately 25 cfs discharge e
Recycle gates open e
All cooling towers in service with maximum practical number of fans on The same transition period is required to bring the system back to closed cycle operation as that required for a change to helper cycle to prevent cold shock of fish.
- Thus, about three days will be required af ter Phase One to begin Phase Two treatment.
During Phase Two, a single discharge gate will be opened to allow a discharge of approximately 25 cfs to prevent water from passing under the skimmer wall at die plant intake canal.
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NORTHERN CTT'ATED POWER COMPANY
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Page 7 P I Chlorination Plan MPCA - Oct 25, 1979 2.
Fish Removal Since fish may be residing in the recirculation canal, attempts will be made to remove them prior to the start of Phase Two.
Options available are electro-shocking or seining with subsequent reintroduction of fish out-side the circulating water system or the application of a fish dispersant (0.3 mg/l CuSO ).
The latter 4
option will be conducted in conjunction with MDNR personnel.
3.
Chlorination The chlorination and biodispersant chemicals and injection points are the same as for Phase One.
The intent of Phase Two is to operate the circulating water system closed cycle, chlorinate to 2 mg/l free chlorine and hold that concentration for six hours.
Lab tests of the six-hour chlorine demand of the recirculation canal water indicate a dose of 13 mg/l to maintain 2 mg/l free.
The lab tests utilized to determine chlorine demand were not able to determine the additional demand of the entire circulating water system due to the presence of slime in the cooling towers, sediment in the canals, etc.
- Thus, the total amount of chlorine required will doubtlessly be greater than 13 mg/1.
Monitoring of the free chlorine concentration in the system will dictate what additional chlorine will be required to maintain a 2 mg/l concentra-tion for the six-hour period.
4.
Monitoring 1
e Sample point location 1)
Cooling tower pump discharge - Sample Point 1 2)
Discharge Canal - Sample Point 3 l
3)
Inlet to condenser - Sample Point 4 1
4)
Recirculation canal - Sample Point 5 l
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F NORTHERN GTATED POWER COMPANY Page 8 P I Chlorination Plan MPCA - Oct 25, 1979 e
Chlorine Measurement Tast Methods 1)
Iodometric titration ~ utilizing amperometric end point 2)
DPD colorimetric e
Monitoring Frequency 1)
Grab samples from Points 1 and 3 will be taken at 30 minute intervals during the chlorination treatment 2)
Grab samples from Point 4 will be taken at 30 minute intervals 3)
Grab samples from Point 5 will be taken periodically Sample Point 1 was selected to provide information on the maximum chlorine concentration in the system.
Sample Point 4 is located at the inlet to the condensers and will provide information at the "end of the loop" where the chlorine concentration is expected to be the least.
- Thus, Point 4 will dictate additional requirements to add chlorine to maintain 2 mg/l free.
Random samples from the recircula-tion canal (Point 5) will be used to assess completeness of mixing and provide further information on chlorine concentration in the system.
Sample Point 3 will indicate the effectiveness of dechlorination.
As in Phase One, both amp:rometric titration and DPD color-metric procedures will be utilized.
The monitoring fre-quency indicated above will be the minimum amount of monitoring.
Additional testing at these and other points is likely.
l' NORTHERN CTATED POWER COMPANY Page 9 P I Chlorination Plan MPCA - Oct 25, 1979 5.
Dechlorination e
Dechlorination chemical:
liquid sodium' sulfite o
Dechlorination injection point:
cooling tower pu=p bay e
Dechlorination injection method:
pumped from truck tanker at known pumping rates The dechlorination will co==ence after the circulating water system has been exposed to 2 =g/l free chlorine for six hours.
Based on the amount of chlorine added and the concentration of chlorine in the system, a calculation prior to dechlorination will provide the amount of sodium sulfite to add.
The dechlorination will continue until chlorine concentrations in the system are less than the detection limit ( 4 0.05 mg/1) as measured by amperometric titration.
6.
Monitoring during dechlorination The same monitoring points and test methods will be used as in the chlorination phase.
7.
Discharge of dechlorinated water Once sample analyses show total chlorine residual con-centrations less than detection at sample Points 1, 4, and 5, the discharge gates will be opened and the plant will return to its normal operating mode.
Grab samples will be taken from the discharge canal during discharge at 15 minute intervals for 90 minutes.
Page 10 P I Cnlorination Plan MPCA - Oct 25, 1979 8.
Environmental Assessment Since there is a potential for fish mortality during this treatment, an impingement survey will be conducted.
Additienc11y, any impacts associated with the chlorinated cooling tower drift will be assessed.
9.
Sampling for Nacq1 aria fowleri Aftor completion of the treatment procedure, samples will be collected and checked for N.
fouleri.
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R D CLOUGH, ASSISTALIT ADMINISTPXIOR Special Projects jP cc:
Howard Krosch, MDNR Ruscell Frazier, Mil Health Department 1
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m Minnesota Pollution Control Agency OCT 2 91979 R.
D.
Clough, Assistant Administrator Special Projects Regulatory Compliaace and Services Northern States Power Company 414 Nicollet Mall Minneapolis, Minnesota 55401 Re:
NSP - Prairie Island Nuclear Generating Plant Chlorination Plan for Circulating Water Treatment
Dear Mr. Clough:
We have received and reviewed the proposal for chlorination of the cooling water system to eliminate the parasitic amoeba at the Prairie Island Plant.
It is our understanding that the chlorination program would proceed under two phases.
Phase I consists of chlorination of the cooling towers under helper mode cooling operation with subsequent dechlorination prior to discharge.
Phase II consists of chlorination of the total circulating water system under closed cycle cooling operation with minimum blowdown and subsequent dechlorination prior to discharge.
In order to prevent cold shock fish mortality a gradual transition from the present operation to helper cycle is proposed.
Initiation of this transition is proposed to begin Sunday, October 28, 1979, with full helper cycle beginning Wednesday, October 31, 1979, during which Phase I chlorination / dechlorination commences.
Previous to chlorination, copper sulfate will be added under recommendation from the Minnesota Department of Natural Resources, in order to aid removal of any fish residing in the cooling tower return canal.
It is also our understanding that fish removal by some means will be undertaken to remove fish from the recirculation canal previous to Phase II chlorination.
1935 West County Road 82, Roseville. Minnesota 55113 Regional Othces. Duluth I Brainerd / Detroit Lakes / Marsha:1 : Rochester / Roseville Equal opportunity Empeyer
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Mr.
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D. Clough Page Two Minnesota Pollution Control Agency staff approve of this plan for chlorination / dechlorination as described in your letter of October 26, 1979, which details the proposed plan.
- However, we_are concerned about requirements for future chlorinatic We believe it is important to comprehensively evaluate the succ.ess of the chlorination program to obtain substantial data for future use should the amoeba problem reoccur.
Therefore, we are requesting that a report be submitted to this office within six weeks after the chlorination program concludes.
This report should include all chlorine monitoring data and monitoring for the presence of the amoeba after chlorination.
Should you have any questions regarding this approval please contact Don Kriens of my staff at 612-296-7363.
Sincerely
~~.. :u (Ybb Terry Hof an Executive Director TH/dc cc:
Howard Korsch, Department of Natural Resources Russell Frazier, Department of Health
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