ML18029A232
| ML18029A232 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/02/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| GL-84-07, GL-84-7, NUDOCS 8411060223 | |
| Download: ML18029A232 (16) | |
Text
REGULATOR~NFORMATION DISTRIBUTION S l'EM (RIDS)
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ACCESS'CON NSR: 8411060223 DOC, DATE: 84/11/02 NOTARIZED:
YES DOCKET' FACIL:50-259 Browns Ferry Nuclear Power Stationi Unit 1, Tennessee 05000259 AUTHNAME AUTHOR AFFILIATION MILLSg L ~ M Tennessee Valley Authority RECIP ~ NAME RECIPIENT AFFILIATION DENTONgH ~ R, Office of Nuclear Reactor Regulationi Director
SUBJECT:
Forwards ALARA program description re replacement of stainless steel piping subj to EGSCCiin response to Generic Ltr 84-07'Procedure Guidance for Pipe Replacement at B'NRs ~ "
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TENNESSEE VALLEYAVTHORlTY CHATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II November 2, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Mr. Denton:
In the Matter of the Tennessee Valley Authority Docket No. 50-259 We have reviewed NRC's letter from D. G. Eisenhut to All Licensees of BWRs dated March 14, 1984, subject, Procedural Guidance for Pipe Replacement at BWRs (Generic Letter 84-07).
We-plan to replace stainless steel piping subject to intergr anular str ess corrosion cracking at Browns Ferry Nuclear Plant unit 1.
As requested by the generic letter, we are submitting the ALARA Pr ogram Description for Browns Ferry pipe replacement.
If you have any questions, please get in touch with us thr ough the Browns Ferry Project Manager.
Very truly yours,
,. Subscribe goal sworn to me this day of TENN SSEE VALLEY AUTHORITY L. M. Mills, anager Nuclear Licensing fore r
1984.
Notar y Public My Commission Expires Enclosure cc (Enclosure):
U.S. Nuclear Regulatory Commission Region II ATTN:
James P. 0!Reilly, Regional Administrator
'01 Marietta Street, NW, Suite 2900
,Atlanta, Georgia 30323 I
Mr. R. J. Clark Br owns Ferry. Project, Manager U.S. Nuclear Regulatory'Commission 7920 Norfolk Avenue
- Bethesda, Maryland 20814 84iiob0223 5000259 84ii02 pDR pDQCK 0 po P
An Equal Opportunity Employer
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ENCLOSURE TENNESSEE VALLEY AUTHORITY ALARA PROGRAM DESCRIPTION FOR BROWNS FERRY NUCLEAR PLANT PIPE REPLACEMENT Oct:obex 1984
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ALARA PROGRAM DESCRIPTION FOR BROWNS PERRY NUCLEAR PLANT PIPE REPLAC&KNT Introduction The Tennessee Valley Authority (TVA) has elected to replace stainless steel piping subject to intergranular stress corrosion cracking at the Browns Ferry Nuclear Plant (BFN) unit 1.
The pipe replacement is scheduled during the 200-day cycle 6 outage beginning March 22, 1985.
I Morrison-Knudsen Company, Inc.
(M-K) has been awarded a contract to provide preplanning, engineering
- support, procedures, quality assurance/control, welding, craft management, and manpower for the pipe replacement project.
The piping and components that will be replaced include all of the reactor recirculation process pipe and the inlet safe ends, the residual heat removal pipe from just inside the drywell penetration to the recirculation system tie-in, the reactor water cleanup pipe including the penetration, and the core spray pipe from the reactor to the inboard check valves including the safe ends.
The existing valves and pumps will be reinstalled in the new system.
This report outlines the objectives,
- means, and actions planned to accomplish this work consistent with maintaining radiation doses as low as is reasonably achievable (ALARA)~
Ob'ectives During the pipe replacement project at BFN, radiation doses to personnel will be maintained individually and collectively ALARA.
The principles of Regulatory Guides 8.8 and 8.10 will be used in designing and operating the ALARA program.
The requirements of 10 CFR 20 and the plant technical specifications will be fulfilled.
Or anizational Structure for Maintainin Doses ALARA Health physicists from TVA and contractor organizations will work together and will interact with plant management,
- crafts, and contractor organizations to maintain doses ALARA.
1.
Plant Health Physics Organizations The plant health physics organization will be responsible for health physics during the outage.
These duties will include surveys, approval of special work permits, internal and external exposure control, dosimetry, training, respiratory protection, ALARA planning, and work package and procedure review.
No modifications of health physics procedures and practices are anticipated for this outage.
Ample health physics personnel will be assigned to the project.
a.
Outage Health Physics An outage health physics group is a part of the plant health physics organization and reports to the plant health physicist.
This outage group will provide day-to-day health physics coverage for this project.
b.
ALARA Engineer An ALARA engineer is a part of the plant health physics organization and reports to the plant health physicist.
The ALARA engineer evaluates work with significant potential for exposure and recommends methods for exposure reduction.
The engineer tracks doses as work progresses.
If the doses are exceeding the estimates, the engineer recommends methods of exposure reduction.
Several health physics technicians are assigned to assist with these responsibilities.
2.
Piping Replacement Project Health Physicist When it was decided to replace the piping at BPN, a piping replacement
project organization was formed.
This organization contains a health lg phys<cist'to assist in making decisions "xn 'the engineering and planning of the work.
This health physicist reviews all work packages and proposed procedures and makes recommendations on good radiation protection practices.
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M-K Health Physics Personnel M-K also has a health physics organization onsite.
The health physicists are responsible for personnel training, work package and procedure review, shield-II, ing design, and recommendations for radiation protection.
Reactor Confi uration During the pipe cutout and replacement, the reactor and internals will be a major source of radiation.
Since the water in the annulus and core barrel will be lowered due to potential leakage in the jet pump diffusers, the radiation levels around the'vessel will potentially be higher than would normally be expected.
There are several methods of exposure reduction that will be implemented and/or are being evaluated.
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The fuel will be removed from the core and stored in the spent fuel storage area.
2.
The control blades are very radioactive, and the upper ends of the blades contain the greatest concentration of radioactive material.
The blades will be positioned to increase the distance from the blades to the work area.
3.
The steam dryer and steam separator are also very radioactive.
The dryer and separator are normally stored during outages in the equipment pit, which is flooded with the cavity to reduce radiation levels on the refueling floor.
However, since the water level in the vessel will be lowered, the equipment pit cannot be easily flooded.
Evaluations are being conducted to determine the best methods for shielding the dryer and separator during the outage.
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Due to the low water level in the vessel, the exposure rates on the refueling floor could be higher than normal for an outage.
Therefore, the vessel will be shielded to reduce exposure levels.
5.
Many man-hours will be spent around the recirculation suction and discharge nozzles.
Shielding will be provided in and around the nozzles to reduce the exposure rates to the workers.
Work Plannin Work packages and procedures will be written to govern all work within the drywell in support of piping replacement.
These work packages will be reviewed by the health physicist on the piping replacement project.
Recommendations will be made, if appropriate, on methods of exposure reduction.
Em lo ee Trainin Mockups may be used to train workers for gobs that may be unusually difficult or may involve high exposure potential.
Mockups of recirculation suction and discharge nozzles will be used as a minimum.
Training in radiation protection will be provided to workers on this project identical to the training provided all radiation workers.
Chemical Decontamination Chemical decontamination of pipes removes internally deposited radioactivity and reduces the exposure rates around the pipes.
Therefore, the piping will be decontaminated prior to significant work on the drywell.
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Contamination Control The drywell will be a contamination zone.
Therefore, appropriate procedures, fl'nstrumentation, and protective clothing will be available to prevent the spread Ill ~
of uncon trolled radioactive contamination ou ts ide the drywell.
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Radioactive contamination can accumulate inside the drywell to the point that airborne radioactivity is possible and exposure rates are significant.
Before this point is reached, areas within the drywell will be decontaminated to acceptable levels.
Airborne Radioactivit Welding and cutting operations have the potential for generating airborne radioactivity.
Pipe cutting techniques will be selected, if feasible, to reduce the potential for airborne radioactivity. If airborne radioactivity levels cannot be kept below the levels specified in 10 CFR 20, respiratory protective devices will be provided in accordance with 10 CFR 20.
Adequate drywell ventilation will be provided to remove potentially contaminated air from the drywell and the worker's breathing zone.
Dose Trackin and Control All radiation workers are issued direct-reading dosimeters (DRDs) and thermolu-minescent dosimeters (TLDs) to measure external doses of radiation.
DRDs will be read each time a worker exits the drywell.
Day-to-day exposure control is achieved by entering DRD readings into a computer that provides printouts on each shift of total quarterly and yearly doses.
TLDs can be read onsite to provide a legal record and to ensure that the limits stated in 10 CFR 20 are not exceeded.
Pro'ect Dose Estimates Dose estimates for the entire project and for individual parts of the project have been formulated.
These estimates are preliminary, and as additional
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information becomes available these estimates will be refined.
As the work progresses, jobs that are causing doses higher than anticipated will be reevaluated to determine if changes, can be made to lower exposures.
These dose estimates were obtained by determining man-hours in radiation fields.
Exposure rates measured in-the last unit 1 outage were corrected for increased operating history, low water level in the core, and other dose reduction techniques to yield the anticipated exposure rates.
It is estimated that the total dose for this project will be 1924 man-rem.
Radioactive Waste There will be two potentially significant sources of radioactive waste from this project.
Disposal of the old piping must be properly handled.
The piping or waste result-ing from pipe decontamination will be buried at a licensed burial facility.
As a result of pipe decontamination prior to removal from the drywell, solidified radioactive waste will be generated.
The contractor will be responsible for packaging and shipping the radioactive waste generated as a result of the chemical cleaning.
TVA will provide allocation space and disposal for the solidified waste at a. licensed burial facility.
The contractor will be responsible for the waste during shipping.
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