ML17325A496
| ML17325A496 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/23/1987 |
| From: | Wigginton D Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17325A495 | List: |
| References | |
| NUDOCS 8712040209 | |
| Download: ML17325A496 (19) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 ENVlRONMENTAL ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE REPAIR OF STEAM GENERATORS INDIANA AND MICHIGAN POWER COMPANY DONALD C.
COOK NUCLEAR PLANT, UNIT NO.
2 DOCKET NO. 50-316 Dqt:e: November 23, 1987
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TABLE OF CONTENTS
- 1. 0 INTRODUCTION 2.0 NEED FOR THE PROPOSED ACTION 3.0 ALTERNATIVES TO THE PROPOSED ACTION 3.1 Retubing 3.2 Sleeving 3.3 Continued Operation 3.4 Shutdown 4.0 ECONOMIC COSTS AND BENEFITS OF STEAM GENERATOR REPLACEMENT 4.1 Economic Costs 4.2 Economic Benefits 4.3
.Shutdown Alternative 4.4 Conclusion 5.0 ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTION 5.1 Radiological Impacts 5.1.1 Increase in Occupational Exposure 5.1.2 Risks Attributable to Occupational Exposure
- 5. 1.3 Offsite Radiological Exposure from Plume Pathway 5.1.4 Impacts from Solid Waste (Excluding Steam Generator Assemblies)
- 5. 1.5 Impacts from Solid Wastes (Steam Generator Assemblies) 5.1.6 Doses from Onsite Storage of Steam Generator Assemblies P
5.1.7 Effect of Repair on Future Normal Operation 5.1.8 Radiological Impact Conclusion 5.2 Nonradiological Impacts 6.0 ALTERNATIVE USE OF RESOURCES 7.0 AGENCIES AND PERSONS CONSULTED 8.0 BASIS AND CONCLUSIONS FOR NOT PREPARING AN ENVIRONMENTAL IMPACT STATEMENT
9.0 REFERENCES
- 1. 0 INTRODUCTION By letter dated March 12, 1987, the Indiana and Michigan Electric Company (the licensee) requested an amendment to Facility Operating License No. DPR-74.
The amendment would permit the repair by replacement of major components in all four steam generators of Donald C.
Cook Nuclear Plant, Unit No. 2.
The granting of the proposed amendment would allow the licensee to repair the four steam generators in Unit No.
2 in accordance with the Steam Generator Report (the Report) submitted by the licensee by letter dated November 7, 1986, as revised by the licensee on March 30 and July 24, 1987 based on the ongoing Commission review.
The four steam generators have incurred intergranular attack/
stress corrosion cracking of tubes in the tubesheet region and in the tube support regions.
The tube sheet region cracking could be corrected somewhat by sleeving the tube ends; however, the tube support regions can be corrected only by plugging all the affected tubes.
As of November 1986, the licensee has plugged 763 tubes and, to limit further chemical corrosion, has initiated an on-line boric acid treatment of the steam side of the tubes and is administratively limiting the unit to 80% power; this latter effort is to further reduce the high temperature sensitive, corrosion attack.
As a result of continued tube degradation, the associated penalty of reduced generating
- capacity, and the lack of practical repair techniques, the licensee is proposing to replace the half of each of the steam generators containing the tubes.
The licensee will take advantage of the required replacement to also refurbish the remaining half of each steam generator to ultimately improve and enhance steam generator and plant performance.
The repair program will involve partial disassembly of the reinforced concrete enclosures surrounding the steam generators, cutting and removing portions of the steam lines and feedwater lines, cutting the inlet and outlet reactor coolant lines, cutting the steam generators in half to preserve and refurbish the upper assemblies and to replace the lower assemblies (all tubes, tube supports, and tubesheet),
moving and storing the used lower assemblies on-site until eventual plant decommissioning, and reassembling the unit with new lower assemblies in the reverse order.
To accomplish this effort, the licensee will improve several existing roads to facilitate movement of contractor personnel on-site and to accommodate the movement of the lower assemblies to the storage area, build a new storage building to house the used lower assemblies until decommissioning, build a
new site security access building and a containment access building to facilitate contractor access as required, and erect a fabrication shop/warehouse for repair, storage, and training.
All of these activities will be accomplished within areas already impacted by plant construction and operation.
2.0 NEED FOR THE PROPOSED ACTION The ongoing program to plug affected tubes will eventually lead to derating the licensed power level of the unit.
As more tubes are plugged, the unit has less capability to remove reactor heat.
As this capability diminishes, the licensed power level would be decreased to maintain appropriate safety and operational limits.
The ongoing program also includes an administrative limit imposed by the licensee at 80% of the approved power level in order to further decrease the corrosion attack on the tubes.
The proposed repair program will allow the unit to efficiently operate again at its design capacity.
3.0 ALTERNATIVES TO THE PROPOSED ACTION The alternatives to the repair program are:
( 1) retubing the steam generators in place; (2) sleeving the steam generator tubes; (3) no change in operation at reduced power; and (4) shutting down the unit and relying on alternative power supplies.
Each of these was examined against technical feasibility and/or cost.
To the extent that alternatives are feasible, the costs are discussed in Section 4.
The alternatives to disposal of the steam generator lower assemblies is off-site storage and disposal at a licensed burial facility.
This would involve intact shipment or sectioning of the entire lower assembly including the tubes at the site.
The intact shipment of contaminated assemblies is not feasible with casks available today and decontaminating the assemblies would be required for the intact shipment or sectioning assemblies to fit available casks.
The licensee has included the cost of on-site storage in their overall cost estimates.
3.1
~Retubin Retubing steam generators has been investigated by Westinghouse and determined in its judgement to be feasible;
- however, no licensee has proposed this alternative and the staff has not reviewed it.
The process would require all of the proposed repair program except removal of the lower assemblies as a sealed unit (caps will be welded on all the openings of the lower assembly before removal in order to contain the radioactivity in and around the tubes).
Retubing the lower assemblies would require a
complex cutting and extraction process to remove the old tubes, a new container or cask to store or dispose of the radioactive tubes, and an in-place, retubing to a contaminated tubesheet.
This process has not been previously used or demonstrated for a nuclear power plant.
As a result the specific safety and environmental impacts of the use of such a process would be very difficult to predict at this stage.
In view of'he complexity of the process for in-place cutting and removal of old tubes followed by in-place retubing, and in view of the fact that the process has not been demonstrated at a nuclear power plant, the staff concludes that there is not sufficient information available to determine that retubing is a reasonable alternative to the licensee's proposal.
3.2
~Sleevin Sleeving the steam generator tubes was considered viable until corrosion cracks were also discovered in the tube support areas.
The tube support areas are at varying elevations along the tube and at the U-bends.
Sleeves at the tube sheet (inlet or outlet of the tube) and over a limited straight portion of an easily accessible tube can prolong the life of the tube; however, the feasibility of sleeving along the tube length and in curved portions has not been demonstrated and is highly questionable.
The staff agrees that this alternative is not a reasonable alternative to steam generator replacement.
3.3 No Chan e in Present 0 eration Continuing to operate the unit indefinitely at 80Ã power could be done if the corrosion has been arrested at the tube sheet crevices and at the tube supports.
In such a case, periodic shutdowns and inspections would be required to provide this assurance.
Indefinitely continued operation of the facility at a maximum of 80$ rated power has been evaluated in section 4.2 below.
However, inspections to date have not provided assurance that the corrosion has been arrested.
If corrosion control has not been effective, tube degradation would be expected to continue.
This would cause a continued reduction in power to compensate for further reduction in heat transfer surface.
Eventually, the power would be reduced to uneconomic levels and the plant would be forced to shut down.
Continued tube degradation would also mean an increased likelihood of sudden tube ruptures.
While such events are within the capability of the plant to safely handle, such events result in undesirable transients and may even-tually adversely affect plant safety.
In the absence of any indication that corrosion has been arrested, continued indefinite operation is not a reasonable alternative.
3.4 Shutdown Shutting down the unit and relying on alternative power supplies is possible and is discussed below.
4.0 COSTS AND BENEFITS OF STEAM GENERATOR REPLACEMENT By replacing the steam generator, Indiana and Michigan Electric Company estimates that there will be a savings of more than
$ 100 million over the.
remaining 20-year plant life compared to the economically next best alternative, which is continuing to operate at the reduced power level of 80% of rated power.
The analysis was done optimistically assuming there would be no further degrada-tion of the steam generators.
In the actual situation, this degradation is a
gradual phenomenon and the most likely outcome is that the steam generators would be completely incapable of performing their functions safely, well before the end of the plant life.
Thus, at some point in the life of the reactor, the only choice is between replacing the steam generators or shutting down the plant.
4.1 Economic Costs The licensee estimates that the repair of the four Unit 2 steam generators in the manner described will require a total capital expenditure of $161.9 million.
This includes labor, equipment, and other charges such as overhead, contingency funds, escalation, and allowance for funds used during construction.
Downtime attributed solely to the replacement project is expected to last 39 weeks; The additional cost of replacement power is expected to be
$62.6 million.
This is derived from fuel and operating costs estimated to be
$20w79 per MWh from alternative sources and
$9.92 per MWh from D. C.
Cook, Unit 2.
This difference of $ 10.87
($20.79 - $9.92) per MWh will be referred to as the fuel cost differential.
The total dollar impact of the replacement project is expected by the licensee to be
$224.5 million.
The staff has evaluated the reasonableness of these expected costs by use of available generic information.
Generic capital cost estimates (Reference 1) are obtained by evaluating the materials, equipment and personnel costs for four phases:
IlI (3)
(4 entry and preparation activities removal and storage activities installation activities, and post-installation activities.
To these costs are added shutdown and startup costs (Reference 2).
These latter costs are minor and the upper range of about
$ 150,000 does not affect overall totals to any measurable extent.
Generic cost estimates for the replacement proiect itself are given for a 750 MWe and a 1,300 MWe plant.
These costs are, respectively,
$90 million and
$ 110 million.
Since many of these costs are not sensitive to plant
- size, a total of less than
$ 100 million should be expected for the 1,100 MWe D. C. Cook, Unit 2 plant.
Since these costs are in 1984 dollars, an inflation adjustment should be made.
The licensee indicates that the repair project will take place in the 1988 time frame.
Applying an 8 percent annual inflation rate, as recom-mended (Reference 1), brings the
$ 100 million to $ 136.6 million.
Replacement energy costs for the 39-week outage can be estimated from a plant-by-plant study (Reference 3).
For D. C.
Cook Unit 2, the estimate is
$72.3 million.
The total of the staff's generic cost estimate, including the job itself, shutdown and startup, and replacement power, is
$207.5 million.
Given the various uncertainties in these figures, a reasonable estimate range is
$200 to
$ 250 million.
The staff, therefore, concludes that the licensee's estimate of $224.5 million is reasonable.
4.2 Economic 8enefits The benefits of the project are the avoidance of costs associated with the reduction to 80K maximum power, even assuming that no further reductions would be required.
The licensee estimates that replacement power and loss of sales costs over a 20-year period (the remaining life of D. C. Cook, Unit 2) is
$35 million per year in order to replace the 20%
of power lost due to degradation.
Apparently, the licensee escalates the fuel cost differential by 4 and 6 percent per year.
The staff considers these to be reasonable estimates.
With these figures, the licensee estimates the present value of differential fuel costs at over
$325 million, thus deriving a net benefit of over $ 100 million.
The staff does not have an independent basis for estimating this cost differential.
Mhile Reference 3 provided replacement power costs, the estimates are not valid for a long-term loss of capacity.
This is so primarily because, on a long-term basis, utilities would probably seek out lower cost solutions to the loss of a nuclear plant.
Nore generally there
's low reliability to a forecast of fuel and operating cost differentials over a 20-year period.
For this reason, the staff did not apply an escalation factor to the fuel cost differential.
8ased on past experience, it is reasonable to expect at least a modestly higher cost by using fossil-fuel plants rather than nuclear.
Thus, the licensee's estimate of an annual
$35 million difference is reasonable.
For a 20-year period, this has a present value of $251.9 million using the licensee's discount rate of 12.6 percent but without escalation of fuel cost differential.
To demonstrate the effects of a lower and perhaps more reasonable discount rate of 6 percent, the present value of the differential is
$401.4 million.
Comparing these to the licensee's estimated repair cost of $200 to $250 million shows the economic reasonableness of proceeding with the replacement.
The environmental effects of continuing to operate at 80% rated power rather than replacing steam generators would be a saving of: the 1733 person-rem occupational exposure associated with the replacement (see Sec.
- 5. 1. 1.), the small increment of solid waste (Sec. 5.1.4), the limited construction impacts associated with upgrading of roads and construction of the steam generator storage building (Sec.
5.2) and the insignificant dose from the storage building.
On the other hand, continued operation with degraded steam generator tubes would require frequent inspection, approximately every 6 months, of the steam generator tubes to determine whether additional corrosion has taken place.
This would result in a continuation or increase in the current occupational exposure resulting from these exposure intensive inspections.
The exposure due to the repair effort would be associated only with the repair and would not continue into the future, but the exposure associated with 6 month steam generator inspections would continue indefinitely into the future and in fact may cumulate to a substantial portion of the exposure associated with the repair effort.
In addition, although offsite radiation release from the Cook facility is not substantial under current operating conditions, steam generator repair would tend to improve offsite release to some extent.
In summary, even if it were assumed that the Cook plant could operate at a maximum of 805 of rated power indefinitely into the future, replacement of the steam generators and return to full power operation would be economically beneficial and would not result in significantly greater environmental impacts.
Nore important, as noted above, in the absence of any indication that corrosion has been arrested, indefinitely continued operation at a substantial power level (such as 805 of rated power) is not a feasible alternative.
4.3 Shutdown Alternative The only other available alternative to the replacement of the steam gener-ators is a permanent shutdown of D.
C. Cook, Unit 2, and eventual replace-ment with new generating capacity.
Since the degradation of the present steam generators is a gradual phenomenon, the unit could continue to operate in its current, albeit restricted, condition during the approximately 8 years needed to construct a fossil-fuel unit.
The additional costs during construction would be the differential fuel costs to make up for the restricted power level during construction of the replacement facility.
Beyond this period, the cost of the new capacity plus the differential fuel costs of operating the new facility would be attributable to the degredation of the D. C. Cook, Unit 2, steam generators.
With these assumptions and using the licensee's unit cost estimates, the estimated cost of this alternative can be derived.
The differential estimated fuel cost, as noted above, is
$ 35 million per year, with a 20-year present value of $251.9 million.
The capital cost, which would be charged from the 9th year (following an 8-year construction period) to the 20th year is estimated to be between
$ 1378/kW and
$2091/kW, or between
$690 million and
$1.045 billion in present value terms.
This represents only the capital charge attributable to years 9 through 20, not the present value of the entire capital cost of a new 1100 MWe coal fired plant.
Therefore, total operating and capital costs for a coal fired alternative are estimated at between
$ 942 million and
$1.299 billion.
This alternative, while distinctly less attractive than the steam generator replacement, is at a substantially lower cost than the licensee's estimates of between
$2.2 billion and
$3.4 billion.. The reasons for this difference are apparently the following.
(1)
Fuel cost differential is escalated by the licensee at 4-and 6-percent per year.
The staff did not escalate due to the high uncertainty in long-term differential fuel costs.
(2)
The replacement source was assumed to be a 1,300 MWe coal-fuel plant.
The staff assumed an 1,100 MWe unit to just replace D.
C. Cook, Unit 2.
(3)
Capital costs of the rep'lacement plant were presumably counted for 20 years - 1990 to 2009.
The staff assumed only capital costs after a replacement plant could be built - years 9 through 20.
Prior to that time, new plant costs are not counted.
Omitted from both the licensee's and staff's cost summation is the cost which would be incurred ff the licensee had to purchase firm power to assure adequate capacity during the time when D. C. Cook, Unit 2, is under restricted power.
This could be significant, but almost certainly less than the annual investment carrying charge of a replacement faci'lity.
Permanent shutdown of D.C. Cook, Unit 2 after the 8 years assumed to build replacement power would involve other environmental costs which can be compared to the economic costs.
The savings of yearly occupational doses at 345 person-rems (see page 8) for the years 9 thru 20 would amount to just over 4000 person-rems.
The doses to the public from reduced effluent releases would be much less and insignificant in comparison; typically I/100 of the occupational dose or about 40 person-rems.
This savings in environ-mental costs of approximately 4040 person-rems would be. compared to the power generation replacement cost of $942 million to
$ 1.299 billion.
The staff agrees that the alternative to the steam generator replacement, i.e.
permanent shutdown, is not economically cost beneficial.
- Further, replacement of power from Cook by power from a fossil plant would result in environmental impact associated with operation of fossil plants and any environmental benefits from shutdown of Cook would be offset by the environmental impacts of operating a fossil fired replacement.
These relative impacts were considered at the time that Cook was initially licensed.
The NRC staff concluded that the overall environmental impact to be expected from operation of either a coal-fired or oil-fired alter-native would exceed those expected from the Cook plant.
See "Final Environmental Statement Related to Operation of Donald C.
Cook Nuclear Plant Units I and 2, Indiana 8 Michigan Electric Company and Indiana 8
Michigan Power
- Company, Dockets Nos.
50-315 and 50-316," August 1973.
Thus, there would be no significant environmental benefit from shutdown of Cook.
To bound this discussion, we have also considered the effect of immediate shutdown of Cook facility.
Such shutdown is not required by safety or environmental requirements in the present condition of the Cook plant.
The licensee has indicated that without the steam generator repair, the unit would continue to be operated for as many years as would be needed to either replace
- power, as generally assumed by the staff's above alternative or until the tube plugging and required power reduction made operation pro-hibitive.
Considering the present condition of Cook, continued operation at reduced power level would be expected for a number of years.
It is important to note that previous replacement projects that considered immediate shutdown as an alternative were units that had 16 to 28K tubes plugged and power limited from 50 to 80%.
Immediate shutdown was a real consideration for those plants.
The D. C.
Cook Unit 2 has only 6 to 7%
tubes plugged with a self imposed power reduction of 80% and might well be expected to operate for years before immediate shutdown can be considered a
reasonable possibility. If the plant were shutdown immediately, replacement of the power supplied by the unit would still be needed as promptly as possible and would require construction of a replacement unit, with the earliest date for operation in about 1998.
Such alternative would involve all of the costs discussed above with the additional cost of purchasing placement power for the entire Cook capacity (1100Mwe) for the period of construction.
This would increase the economic cost of this alternative by a significant amount; perhaps as much as three quarters of a billion dollars.
There would be some additional savings in occupational exposure (i.e. about 2700 person-rem).
- However, as noted above any environmental savings associated with shutdown of Cook would be offset by the environ-mental impacts of fossil plant operation required to provide replacement power and there would be no significant environmental benefit from shutdown of Cook.
4.4 Conclusion An evaluation was done of the licensee's estimates of the costs and bene-fits of the steam generator replacement project.
These estimates were compared by the staff with various generic studies.
The licensee's estimates are consistent with other replacement projects and compare favorably with the staff's 'indepepdent assessment of costs and benefits.
On this basis it is therefore concluded that the licensee's estimates are reasonable and that economic benefits of the replacement project exceed the economic costs.
5.0 ENYIRONMENTAL IMPACTS OF THE PROPOSED ACTION
- 5. 1 Radi pl o ica 1 Im acts The licensee has estimated that the total occupational exposure from the proposed four steam generators (SG) repair program will be 1733 person-rem.
On a per-steam-generator basis this compares favorably with previous repair programs.
The licensee's person-rem estimate per steam generator for Cook Unit 2 is 433 as compared to actual exposures at Sur ry I (586),
Surry 2 (714), Turkey Point 3 (717), Turkey Point 4 (435),
and H. B.
Robinson (402).
On the basis of the staff's review of:
(I) the licensee's report, (2) operational experiences from other repair programs, and (3) as-low-as-is-reasonably-achievable (ALARA) guidelines, that reflect past SG repair programs, the staff concludes that the licensee's estimate of 1733 person-rems to the work force is a reasonable estimate of the expected dose.
- 5. 1.1 Increase In Occu ational Ex osure To determine the relative environmental significance of the estimated occupational dose for the SG repair (1733 person-rem),
the staff compared the estimated dose due to the repair with the reported average dose experienced at modern pressurized water reactors (PWR's).
In addition, the staff also compared the estimated risk to nuclear power plant workers to published risks for other occupations.
Most of the doses to nuclear plant workers result from external exposure to radiation emitted by radioactive materials outside of the body, rather than internal exposure from inhaled or ingested radioactive materials.
Recently licensed 1000 MWe PWR's, as well as major repair projects such as steam generator replacements, are designed in accordance with the post-1975 regulatory requirements and guidelines that place increased emphasis on maintaining occupational exposures at nuclear power plants at "as low as is reasonably achievable" (ALARA) levels.
These requirements and guidelines are outlined in 10 CFR Part 20, and in Standard Review Plan (NUREG-0800)
Chapter 12 (Reference 4), and also Regulatory Guide 8.8, "Information Relevant To Ensuring That Occupational Radiation Exposure At Nuclear Power Stations Will Be As Low As Is Reasonably Achievable," (Reference 5).
The licensee's preliminary proposal to implement the NRC requirements and ALARA guidelines for the SG repair work has been reviewed by the staff and found to be acceptable.
A more detailed review of the licensee's final implementation of NRC ALARA criteria will be reported in the staff's safety evaluation.
Average collective occupational dose information for operating reactors is contained in NUREG-0713, "Occupational Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities,"
1984 (Reference 6).
Informa-tion in NUREG-0713 indicates that the average reactor annual collective dose at U.S.
PWR's has been about 550 person-rem, with some plants experienc-ing an average plant lifetime annual collective dose to date as high as 1400 person-rem.
In addition, the yearly dose range for PWR's has varied widely from year to year (i.e.,
18 to 3223 person-rem per reactor) because of a number of factors, such as the amount of required maintenance and the amount of reactor operations and inplant surveillance.
The dose history for the D.C. Cook nuclear station is contained in NUREG-0713, and Table 7.4-1 of the repair report; with the addition of 1733 person-rem for the repair, the average annual dose for Unit 2 will increase by about 50% from the average of 345 person-rem to 519 person-rem.
The calculated higher annual occupational dose average of 519 person-rem is still well below the 677 person-rem per reactor annual collective doses for LMR (includes" both PWRs and BWRs) facilities (1980 to 1986).
5.1.2 Risks Attributable to Occu ational Ex osure The staff has previously (e.g.,
NUREG-1011; "Final Environmental Statement Related to Steam Generator Repair at Point Beach Nuclear Plant, Unit No. 1, Docket No. 50-266, Wisconsin Electric Power Company,"
September 1983 and NUREG-1003, "Final Environmental Statement Related to Steam Generator Repair at H. B. Robinson Steam Electric Plant, Unit No. 2, Docket No. 50-261, Carolina Power and Light Company,"
November 1983) estimated the risk to nuclear power plant workers and compared it to published risk for other occupations.
On the basis of these comparisons, the staff concludes:
( 1) that the risk to nuclear plant workers from plant operations is comparable to the risks associated with other occupations; and (2) the individual risks associated with exposures involved in the repair will be controlled and limited so as not to exceed the limits set forth in 10 CFR Part 20 for occupational exposure.
Similarly, the staff has previously estimated the health effects resulting from occupational radiation exposures as a result of other steam generator repair projects at Point Beach (NUREG-1011) and at Robinson (NUREG-1003) using the risk estimators of the National Academy of Sciences/National Research
- Council, November 1972, Advisory Committee on the Biological Effects of Ionizing Radiation (HEIR I), "The Effects on Populations of Exposure to Low Levels of Ionizing Radiation."
The risk to the workers at D.C. Cook Unit 2 (1733 person-rem) fs comparable to those other projects which were deemed to be acceptable.
0 Occu ational Ex osure Conclusion In summary, the NRC staff has drawn the following conclusions regarding occupational radiation dose.
The licensee's estimate of about 1733 person-rem for the repair project at D. C. Cook, Unit 2, is reasonable.
This dose falls within the range of annual occupational doses which have been observed in recent years at operating reactors.
Although the dose resulting from the steam generator repair will increase the annual occupational dose average of 345 person-rem to approximately 519 person-rem at D. C.
Cook Unit 2, this is still well below the 677 person-rem per reactor annual collective dose for LMR facilities.
The additional health risks occurring from these doses over normal risks are quite smal'l and are comparable to those calculated in References 7 and 8 for Point Heach Unit I and H. B. Robinson Unit 2 steam generator repair projects.
For the foregoing reasons, the staff concludes that the environmental impact from occupational exposure will not significantly affect the quality of the human environment.
5.1.3 Offsite Radiolo ical Ex osure from Plume Ex osure Public'adiation exposure from the Donald C.
Cook Nuclear Plant, Unit No. 2, steam generator repair can be evaluated by comparing the estimated quanti-ties of radioactive effluents from the steam generator repair >>ith annual average releases from normal operations.
The licensee has estimated the amount of radioactivity that will be released in liquid and gaseous effluents as a result of the repair.
Those estimates are presented in Table 9 (attached).
The staff has reviewed the licensee's estimates and concludes that they are reasonable.
Table I also presents effluent releases for the years
- 1984, 1985, and 1986 as measured by the plant and annual average releases for normal operations estimated previously in the "Final Environmental Statement Related to the Operation of Donald C.
Cook Nuclear Plants Units I and 2," August 1973 (1973 FES).
The expected releases from the repair are less than both the 1973 FES estimates and the station's actual annual releases for normal operations.
In summary, the estimated radioactive releases attributed to the repair are less than those resulting from normal plant operation.
The doses from these releases are small compared with the limits of 40 CFR Part 190 and the annual doses from natural background radiation.
Therefore, the radiological impact of the repair will not significantly affect the quality of the human environment.
Im acts From Solid h'aste Excludin Steam Generator Assemblies The environmental impact of solid radioactive waste from the D. C. Cook, Unit 2, steam generator repair can be estimated by comparing the quantity of solid waste that >>ill result from the repair project with the annual average solid waste generated from normal operations.
The licensee has estimated that the repair efforts on the four steam generators will gene-rate about 41,800 cubic feet (1190 ms) of solid waste containing approxi-mately 52 Curies (Ci) of radioactivity.
This value is lower than the value given in the generic report HUREG/CR-1595, "Radiological Assessment of'team Generator Removal and Replacement,"
December 1980 (Reference 10).
For example, the steam generator repair at Surry, Unit 2, produced about 1618 ms of solid waste containing about 63.6 Ci of activity.
In the years 1984 through
- 1986, D. C. Cook, Units 1 and 2 together, generated an annual quantity of about 21,783 fts (617)(ms)
Of So]id waste Containing approx-imately 1419 Ci.
Therefore, the activity of the solid waste from the repair will be small compared with the annual amount for normal operations.
Since the estimated radioactivity content in the solid waste generated by the repair is small in comparison with the amount contained in solid waste from normal operation, the impact is acceptable, and not significant.
- 5. 1.5 Im acts From Solid Vastes Steam Generator Assemblies Because the removed steam generator assemblies will be stored in a shielded building on the D. C.
Cook site, there will be no solid waste shipments containing radioactive steam generator components.
Ultimate disposal of these steam generator units will be part of the eventual decommissioning of the station.
At that time, approximately 30 additional years of decay will have reduced the radioactivity content of these steam generator units significantly.
Therefore, the radiological impact of the repair project to the public will not significantly affect the human environment.
5.1.6 Doses From Onsite Stora e of Steam Generator Assemblies The licensee estimates that each steam generator will contain approximately 568 Ci of fixed gamma radioactivity at the time the steam generators are removed from the containment.
Four steam generator lower assemblies will be stored onsite in a shielded building.
This building will contain suf-ficient shielding to limit the dose rate to less than 1.0 mrem per hour at the outside of the building.
This building is approximately 1500 ft from the nearest site boundary.
The staff estimates the additional dose rate at the site boundary to be less than 0.000001 mrem per hour from onsit storage of the steam generators.
An individual living an entire year at this location would receive less than 0.01 mrem of radiation exposure from this source.
This dose rate would decrease rapidly during the first 2 year of storage because of decay of short-lived isotopes; thereafter, the dose would decrease by approximately a factor of two every 5 years as the remain Co-60 decayed.
Since the dose estimate given above represents less than a 0.1% increase in natural background dose (approximately 70 mrem) and because it is not credible for an individual to camp at the site boundary for great lengths of time, the staff concludes that the radiation effect to the public from onsite stored steam generator assemblies will be very small and not environmentally significant.
The storage building is greater than 1500 feet from any area where site workers normally work and the exposure from the stored steam generators will be considerably less to the site worker s.
In addition to the storage not being environmentally significant, exposure to site workers will be insignificantly small.
5.1.7 Effect of Re air on Future Normal 0 eration 5,1.8 The repair effort will return the plant to the design conditions on which the staff evaluation in the 1973 FES was based.
Therefore, the staff concludes that the quantity of radioactive materials released from normal operations after the repair should not be significantly greater than those presented in the
- FES, and the potential dose to the public and the impact on biota other than man from those materials will be no greater than the dose impact presented in the FES.
Radiolo ical Im act Conclusion On the basis of its review of the proposed steam generator repair, the staff concludes that:
- 1. The estimated total occupational dose of 1733 person-rem for the repair is within the expected range of. doses incurred, at light-water power reactors in a year.
- 2. The risks to the workers involved in the repair are comparable to the risks associated with othe~ occupations.
- 3. The licensee has taken appropriate steps to ensure that occupational doses will be within the limits of 10 CFR Part 20 and will be maintained as low as is reasonably achievable..
- 4. The estimated doses to the general public are less than those incurred during normal operation at D. C. Cook, Unit 2.
- 5. The repair effort will return the plant to the design conditions on which the staff evaluation in the FES (Ref.
- 10) was based.
5.2 Nonradiolo ical Assessment The repair program will include upgrading of existing roads, new buildings on areas already occupied for plant operation or used during the construction of the plant, and use of the local populace to fill many of the 500 to 600 worker positions.
The licensee has determined that there will be minimal impact on groundwater, surface water, geology, or on the aquatic on terres-trial ecology.
The noise and traffic flow at the beach area will increase somewhat but are only temporary impacts that will end at completion of the program.
The licensee plans noisy operations only during daylight hours or at the latest to about 9:00 p.m.
Any area inadvertently disturbed by the construction machinery will be restored to its original condition.
In addition, there are no known historical, archeological, architectural or natural resources that exist on the site areas affected by the repair program.
The staff has reviewed the licensee's report and agreed with the licensee that there are no significant non-radiological impacts as a result of the repair program.
6.0 ALTERNATIVE USE OF RESOURCES This action does not involve the use of resources not previously considered in connection with the "Final Environmental Statement Related to the Operation of Donald C.
Cook Nuclear Plant Units 1 and 2" dated August 1973 (Reference 10).
7.0 AGENCIES AND PERSONS CONSULTED The staff reviewed the licensee's evaluation that supports the proposed amendment.
The staff acknowledges and appreciates the help of the Division of Radiological Health, Department of Public Health of the State of Yiichigan, especially Mr. Dennis Hahn, Nuclear Facilities and Environmental Monitoring Section Office, in determining beforehand the issues of primary importance to the State of Michigan.
These issues, among others the solid waste discussed in Sections 5.1.4 and 5.1.5, were expanded in the Repair Report and given careful consideration before preparation of this assessment.
8.0 BASIS AND CONCLUSION FOR NOT PREPARING AN ENVIRONMENTAL IMPACT STATEMENT The staff has reviewed the proposed license amendment relative to the requirements set forth in 10 CFR Part 51.
Based on this assessment, the staff'oncludes that there are no significant radiological or nonradiological impacts associated will have no significant impact on the quality of the human environment.
Therefore, pursuant to 10 CFR 51.31, an environmental impact statement need not be prepared for this action.
Dated at Bethesda, Maryland this November 23, 1987.
FOR THE NUCLEAR REGULATORY COYiMISSION
Attachment:
Table 1
David L. Wigginton, Acting Director Project Directorate III-3 Division of Reactor Projects
Table 1
Padioactive Effluents from Steam Generator Repairs and Normal Operations Donald C.
Cook Nuclear Plant Unit 2 Type of Estimated Release Raaioactive SG Repair Effluent Pro 'ect Ci Gaseous Normal Operations, Ci/yr Per Unit, Measure FES-73*
1984 1985 1986 Noble
'e li ible Iodine
- 6. gx10-6 Particulate 2.9x10-4 Tritium Ne li ible 3400 0.2 1750 2470 165 5.9x10-3 6.46xl0-2 8.0xlO 4.6xl0-3 3.72x10-2 3.4x10 25 10.8 3.4 Mixed Fission and Activation Products 0.7 Tritium 250 5.3 0.6 1.13 568 0.25 350 CAFES-1973 estimates are taken from Table III-2 and III-3.
- "no estimate of particulates reported
- no value given in the referenced report
9.0 REFERENCES
1.
Generic Cost Analysis for Steam Generator Repairs and Replacement, EGG-PE-6670, Wayne L. Hiller and Lloyd C. Brown, Idaho National Engineerin Laboratory, August 1984.
~,
1 g
c.
Final Report, Generic Cost Estimates for Reactor Shutdown and Startup, SEA Report No-79-02-A: 1, Science and Engineerino Associates, Inc., et al., June 1984.
3.
Replacement Energy Costs for Nuclear Electricity-generating Units in the United States:
1987-1991, NUREG/CR-4012, October 1984.
4.
"Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants LMR Edition," NUREG-0800, July 1981.
5.
Regulatory Guide 8.8, "Information Relevant to Ensuring that Occupational Radiation Exposures at Nuclear Power Stations Will Be as Low as is Reasonably Achievable," Rev. 3, June 1978.
6.
NUREG-0713 Occupational Rad>ation Exposure at Commercial Nuclear Power Reactors and Other Facilities", 1984.
7.
NUREG-1011, "Final Environmental Statement Related to Steam Generator Repair at Point Beach Nuclear Plant, Unit No. 1, Docket No. 50-266, Wisconsin Electric Power Company,"
September 1983.
8.
NUREG-1003, "Final Environmental Statement Related to Steam Generator Repair at H. B. Robinson Steam Electric Plant, Unit No. 2, Docket No.
50-261, Carolina Power and Light Company,"
November 1983.
9.
National Academy of Sciences/National Research Council, November, 1972, Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR I),
"The Effects on Populations of Exposure to Low Levels of Ionizing Radiation."
10.
"Final Environmental Statement Related to the Operation of Donald C.
Cook Nuclear Plant Units 1 and 2," August 1973.
11.
NUREG/CR-1595, "Radiological Assessment of Steam Generator Removal and Replacement,"
December 1980.
12.
NUREG-0692, "Final Environmental Statement Related to Steam Generator Repair at Surry Power Station, Unit No. 1," July 1980.