ML20028D158
| ML20028D158 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/14/1983 |
| From: | Wilcove M NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| To: | Sheppeard L FEDERAL ENERGY REGULATORY COMMISSION |
| References | |
| ER-593, ER-593-000, ER82-426-600, ER82-610, ER82-610-000, NUDOCS 8301170175 | |
| Download: ML20028D158 (17) | |
Text
January 14, 1983 Laura K. Sheppeard, Esq.
i FERC Staff Counsel Federal Energy Regulatory Comission Washington, D.C.
20426 Re:
Jersey Central Power & Light Company, Docket Nos. ER82-426-600 and ER82-610-000 Pennsylvania Electric Company Docket No. ER82-593-000 Dear Ms. Sheppeard; Enclosed is draft " Testimony of Bernard J. Snyder Concerning the Status of the Three Mile Island Nuclear Station Unit 2 Cleanup and Factors Influencing the Return of the Unit to Service."
Please contact either Dr. Snyder or myself for further assistance in preparing Dr. Snyder's testimony or in any other aspect of the above-mentioned cases.
Sincerely, DISTRIBUTION:
Michael N. Wilcove a{enbury/Scinto Counsel for NRC Staff Lieberman Rutberg cc w/o enclosure: Dr. Bernard J. Snyder ggger Wilcove DE31cua D onic n33 B.Synder Chron Corting 3 OS?
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TESTIMONY OF DR. BERNARD J. SNYDER CONCERNING THE STATUS OF THE THREE MILE ISLAND NUCLEAR STATION UNJT ? CLEANUP AND FACTORS INFLUENCING THE RETURN OF THE UNIT TO SERVICE Q l.
Would you please state your name and position with the NRC?
A 1.
My name is Bernard J. Snyder.
I am the Director of the Three Mile Island Program Office, Office of Nuclear Reactor Regulation, United States Nuclear Regulatory Commission.
Q 2.
Have you prepared a statement of your professional qualifications and the responsibilities of your present position?
A 2.
Yes, a copy of my professional qualifications statement is attached tc this testimony.
Q 3.
Describe the purpose'and subject area of your testimony.
A 3.
The purpose of my testimony is to briefly describe the current status of the Three Mile Island Nuclear Station Unit 2 cleanup effort and to describe the technical and regulatory factors that could influence the decision to return the Three flile Island Nuclear Station Unit 2 to operational service. This testimony does not, however, address costs of returning the unit to service.
Costs are highly dependent on the results of the cleanup activities and subsequent testing and inspection of various plant cocoonents and systems. Any meaningful assessment of costs must, at a minimum, wait until most of the clean-up is completed.
Furthermore, costs would be affected by the pace which the utility sets for returning the unit to service.
This testimony provides a brief description of; (1) the THI-Z accident, (2) the extent of damage as presently known, or reasonably anticipated,
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. (3) the cleanup activities, and (4) technical and regulatory activities influencing the decision to return the unit to service.
Q 4.
Provide a brief description of the 28 liarch 1979 accident at TMI-2.
A 4.
A loss of primary coolant and a reduction of pressure through a pressure relief valve led to a drop in water level, uncovering the upper portion of the reactor core. Due to elevated temperatures in the uncovered portion and subsequent reflooding of the core, rupture of the fuel rod cladding occurred, releasing radioactivity into the primary coolant.
Radionuclides contaminated the reactor building. To a lesser extent the auxiliary fuel handling building (AFHB) was also contaminated principally by the maintenance of reactor coolant water flow through the makeup and purification system for several days following the accident.
A more detailed chronology and description of the accident is found in the NRC document entitled, " Investigation Into the March 28, 1979 Three Mile Island Accident by the Office of Inspection and Enforcement," Investigative Report No. 50-320/79-10, NUREG 0600, dated August 1979.
Q 5.
Describe the known or reasonably anticipated extent of damage to THI-2.
A 5.
The accident resulted in the radioactive contanination of the reactor and auxiliary fuel handling buildings. The reactor building atmosphere was contaminated with gaseous radionuclides, mostly Kr-85, and the reactor building sump was flooded with primary coolant and supplemental cooling water containing radionuclides, nostly Cs-137 and Cs-134 and
, Sr-90. The AFHB was contaminated to a lesser extent by water and gas from the primary system.
Water in the reactor building basement resulting from the accident was attributed to three major sources; primary coolant water, containment spray water, and river water.
River water entered the reactor base-ment as leakage from the containment cooling system. The highly radio-active water in the basement has been removed and decontaminated.
Sludge deposits remain which contain relatively high levels of radio-active cesium and strontium. During the period of time after the accident occurred and before removal of the contaminated water from the basement, migration of long-lived radionuclides of cesium and strontium into the concrete walls and floors of the reactor building occurred. Contamination into the concrete may extend to a depth of inches in some regions. Contamination of equipment and surfaces in the remainder of the reactor building is signifi-cantly less than the contamination in the reactor basement.
Contamination of equipment and surfaces in the AFHB was not as significant or widespread.
The majority of contaminated areas of the AFHB have already been decontaminated; however, the most significantly contaminated cubicles along with the sump have yet to be decontaminated.
A limited closed circuit video examination of the inside of the reactor i
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l pressure vessel was conducted during the summer of 1982. The exami-nation did not reveal severe damage to the upper plenum; however, the TMI-2 fuel was found to be severely damaged over a significant portion
e of the core. The inspection revealed a rubble bed in the center approximately five feet below the top of the core region.
Fractured fuel pellets and pellet retaining springs were visible on top of the rubble.
Non-fuel bearing rods were seen protruding from the rubble bed toward the top of the core.
Some fuel assembly upper end #ittings appeared attached to the underside of the plenum assembly.
Fuel rod stubs were seen protruding downward from some of the upper end fittings.
There appeared to be some melting of structural materials in the area of the upper end fittings.
To the extent of this limited inspection no evidence of uranium oxide fuel melting has been found.
Primary system piping is intact and apparently undamaged; however extensive contamination of the piping with fission products has occurred. During the accident primary to secondary leakage was detected in the B steam generator.
No leakage was detected in the A steam generator.
However, no leakage from either steam generator has been detected since the accident. The extent of steam generator tube failure cannot be determined until decontamination of the primary system has been completed and the steam generators have been inspected.
The pressurizer is intact with little or no suspected damage.
Due to the high temperatures inside the reactor building during the accident and the subsequent high humidity conditions, extensive damage to electrical components and connectors and instrumentation has occurred.
The polar crane controls, cables and electrical components were damaged by the high temperatures during the accident and subsequent
, high humidity conditions. Metal surfaces within the reactor building have experienced varying degrees of corrosion due to the extended period of high humidity conditions. The utility, however, has made no detailed assessment of the extent of damage due to metal corrosion.
Damage to the AFHB is minimal and principally consists of contami-nation. The balance of the plant is essentially undamaged other than repair and refurbishment due principally to the extended period of nonuse.
Q 6.
Briefly describe the TMI-2 cleanup efforts.
A 6.
The goal of the TMI-2 cleanup activities is to decontaminate the facility, defuel the reactor and safely dispose of the radioactive waste and water which resulted from the March 28, 1979 accident.
The cleanup comprises four fundamental activities:
treatment of radioactive liquids; building and equipment decontamination; fuel removal and decontamination of the coolant system; and packaging, hanoling, storage and transportation offsite of nuclear wastes including the entire reactor core. A description of the anticipated cleanup activities is presented in the Final Programmatic Impact Statement (PEIS) related to decontamination and disposal of radio-active wastes resulting from the March 28, 1979 accident at TMI-2 (NUREG-0683) issued March 1981.
Prior to beginning any major cleanup activity the utility is required to submit to the NRC for review and approval a proposal which describes in detail the
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. sequence and scope of the activity along with an evaluation of any safety and environmental inpacts.
The NRC either approves the activity or requires specific changes in accordance with its regula-tory requirements.
Treatment of Radioactive Liquids Large quantities of water were contaminated with fuel debris as a result of the accident. Additional contaminated water has been and will be generated during the efforts to decontaminate the reactor building and during core removal.
Contaminated water has been treated using both the EPICOR-II system and the submerged demineralizer system (SDS). The EPICOR-II system and SDS use ion exchange materials to renove essentially all radio-active contamination except tritium. Approximately 750,000 gallons of moderately contaminated water from the AFHS have been cleaned with the EPICOR-II system. The SDS is being used to decontaminate the approximately 90,000 gallons of highly radioactive water from the primary reactor coolant system (RCS). Also the SDS has been used to clean approximately 600,000 gallons of highly radioactive sump water in the reactor building basement. Approximately 1.7 million gallons of processed accident water are stored onsite and contain about 2600 curies of tritium. The total curie inventory of Sr-90, Cs-134 and Cs-137 (remaining radionuclides in highest concentration) in the processed water is less than 1 curie each.
It has not yet been detemined how the processed accident water will ultimately be
, disposed.
To minimize water contamination, treated water is reused in the plant for decontamination activities and then reprocessed for further use or storage.
Building and Equipment Decontamination Cleanup of the AFHB started with the general areas where contamination was relatively small and is proceeding to cubicles containing tanks and equipment which are more heavily contaminated. Decontamination of better than 80% of equipment and surfaces in the AFHB has been achieved and efforts are continuing.
Decontamination of the reactor building is a much larger effort than decontamination of the AFHB because: (1) the contamination in 'he reactor building is much more severe and widely distributed, (2) the radiation levels are higher, (3) the building consists primarily of large open areas rather than small cubicles, making recontamination a problem, and (4) the size and complexity of the contaminated equipment is much greater.
Decontamination of the reactor basement will likely l
prove particularly troublesome since the sludge contains high levels of cesium and strontium activity and contamination of the concrete surfaces to depths of several inches has probably occurred.
Reactor building decontamination is currently underway.
l Decontamination of the reactor building atmosphere was accomplished l
in June of 1980 by controlled venting of about 43,000 curies of Kr-85 l
gas to the environment.
Defueling and Cooling System Decontamination The objective of this activity is to remove all fuel, damaged reactor
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- parts, and radioactive plateout in the coolant system. The reactor coolant liquid is being decontaminated using the SDS system. Obtain-ing access to the fuel requires the removal of the reactor pressure vessel head and plenum above the fuel.
To remove the reactor pressure vessel head and plenum, the reactor building polar crane, damaged by the environment in the reactor building during and subsequent to the accident, must be refurbished.
Polar crane refurbishment should be completed in the next several months.
Reactor defueling will then require a detailed inspection of the core, removal of debris, and removal of damaged fuel assemblies using special equipment.
Next the fuel support structure must be removed.
If there is warpage and/or mechanical damage of major components such as the plenum or the fuel support structure, underwater cutting and/or machining operations would be required.
Efforts to remove the fuel would then be further delayed.
Having removed all the fuel from the reactor pressure vessel, the final step will be to chemically clean out any residual radioactivity in the primary system using methods analogous to flushing the cooling system of an automobile.
Packaging Handling Storage and Transportation of Radioactive Wastes The wastes resulting from the accident and from decontamination activi-i ties are not all in a form acceptable for offsite disposal.
It will therefore be necessary to decontaminate the contaminated water generated during and subsequent to the accident and to package solid wastes. Wastes are packaged prior to onsite storage or shipment to a waste disposal facility.
Disposal containers for packaging are used for low specific activity material.
DOE is investigating the
-9 need for and development of containers that may be required for the disposal of the SDS zeolite liners, EPICOR-II high specific activity contamiaated resins and the reactor fuel.
Generally all wastes are transferred to an interim onsite storage facility prior to shipment offsite. Wastes have been and will be transported from the site by truck in both unshielded and shielded shipping configurations depending on the specific activity. Low specific activity wastes have been routinely shipped from the site since the accident.
EPICOR-II low specific activity contaminated resins have been shipped to a commercial burial site on the Handford Reservation near Richland, Washington.
EPICOR-II high specific activity contaminated resin liners are also being shipped offsite to the Idaht National Engineering Laboratory (INEL) for DOE spon-sored research activities and/or disposal.
SDS liners are being prepared for shipment. The first two liners were shipped to the Handford Reservation in December 1982.
A Memorandum of Understanding dated 15 March 1982 between the NRC and DOE exists specifying objectives, roles, and responsibilities for removal of the high specific activities wastes including the damaged core.
Also an Agreement in Principle dated 19 March 1982 between DOE and the utility has been signed for acquisition of the danaged TMI-2 reactor core by 00E.
Q 7.
Has General Public Utilities provided the NRC with a program outlining the activities necessary to return the TMI-2 to service?
A 7.
The utility has not submitted to the NRC for review any plan detailing the activities necessary to return TMI-2 to service.
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. Q 8.
Are you aware of any studies conducted by or for the utility to deter-mine the feasibility of returning THI-2 to service?
A 8.
Bechtel Corporation prepared a document entitled, " Containment Recommissioning--Preliminary Assessment of Potential Cost and Schedule" dated July 1979.
In August 1980 the utility published a document entitled, "TMI-2 Recovery Program Estimate" which relied on the information contained in the July 1979 Bechtel study and provided estimates of costs associated with the cleanup and returning the unit to service.
Neither of these documents are of sufficient technical detail to be of significant value in assessing the potential for returning the units to service.
Furthermore since the completion of these two studies much of the information on the extent of damage to the reactor has been updated. To my knowledge, there is no more recent technical evaluation of the feasibility of returning the unit to service.
Q 9.
Provide a description of what steps the utility would have to take beyond the THI-2 cleanup effort to return the unit to service.
A 9.
Significant effort on the part of the utility towards restoration of i
l TMI-2 to service cannot begin until most of the cleanup efforts are l
completed.
It is anticipated that if the utility decides to attempt restoration of TMI-2 a plan would be presented to the NRC for review.
Until the cleanup efforts have been completed, the utility has sub-mitted a plan, and the NRC has conducted a thorough review of this plan, comments on the feasibility and schedule of such an effort
, are speculative. The fact that the extent of damage to the unit is not presently precisely known and the lack of NRC precedent in dealing with such a problem further tempers conclusions to be made on returning the unit to service.
There are at present no known technical factors that have been identified that would foreclose restoring TMI-2 to service. There are, however, a number of non-monetary factors that may likely influence the utility's decision.
These factors can be categorized (1) additional decontamination efforts, (2) inspection, as:
(3) replacement or refurbishment of equipment, (4) requalification of components, (5) upgrading of plant to present NRC standards, and (6) NRC review and associated legal requirements.
Additional Decontamination Efforts Decontamination of the reactor butiding basement to levels that allow routine worker entry may prove difficult because long-lived radio-nuclides may have migrated to a depth of several inches into the concrete surfaces. The use of high purity water to allcw diffusion of radionuclides out of the concrete could be used; however, the time required for such a system to be effective is measured in years.
Shielding of tt? Concrete could also be employed, although the practicali ts +f i :ch an approach has yet to be determined.
Removal of the cor.ac.;. ?cd concrete or replacement is another cption.
Additional decontamination of the remainder of the reactor building and components prior to unit refurbishnent would require an extensive radiological survey and further decontamination of surfaces and
. equipment beyond what is required by the cleanup efforts. The extent of this effort cannot be quantified at this time since there is limited experience with high level decontamination of building interior surfaces and equipment where the contamination has spread over a large area such as the entire surface of a reactor building.
In past instances in which highly contaminated material and equipment were decontaminated, the material and equipment were small and well contained.
Furthennore there is limited experience in the non-destructive decontamination of porous and semi-porous surfaces that have remained contaminated for years.
Inspection A comprehensive inspection program for the primary, secondary, and safety systems as well as other systems and equipment in the reactor building and the AFHB would have to be conducted. Such inspections would appear to be of unprecedented proportions and require extensive and detailed documentation.
Several forms of non-destructive testing would have to be employed and techniques may have to be developed to test and inspect components and systems if they are still con-l taminated.
The magnitude of this effort would be significant and certainly influence the pace of the entire effort.
Replacement or Refurbishment of Equipment l
The precise extent to which equipment and components would have to be replaced or refurbished cannot be detemined until there is a thorough inspection of the various systems. At a ninimum, all of j
the equipment within the reactor pressure vessel and the fuel would
, have to be replaced. The polar crane would require additional refurbishment, as well as extensive replacement of electrical con-trols and electrical connectors.
Much of the instrumentation within the reactor building may have to be replaced. Many valves out of operation since the accident would probably have to be replaced or refurbished.
Piping out of service since the accident would require flushina and possibly chemical cleaning.
Significant amounts of thermal insulation around the primary systems might have to be re-placed.
Various pumps and associated motors inoperative since the accident might need rebuilding.
Repair to one or both of the steam generators might be required.
The long lead time required to order many of these components would certainly influence the pace of recovery operations.
Requalifications One of the greatest uncertainties in returning the unit to service is the ability of the utility to requalify the nuclear steam supply system, in particular the safety related equipment. The reactor pressure vessel was not designed to experience thermal transients similar to those experienced during the accident.
The utility may have a sig-nificant problem in requalifying the pressure vessel and other components forming the primary system pressure boundary particularly since the nature of these transients during the accident cannot be precisely determined. There is no precedent within the industry or within the NRC regulatory framework for requalifying major reactor
. components after an accident that resulted in severe transients and extensive core damage.
Should the utility be unable to requalify the reactor pressure vessel and head, its only alternative would be replacement, a significant undertaking for the utility without precedent within the civilian power industry.
Upgrading of Plant to Present NRC Standards TMI-2 would be required, as are all licensees of operating power reactors and applicants for operating licenses, to implement the TMI Action Plan Requirements (fiUREG-0660) as required in NUREG-0737.
These requirements provide a comprehensive and integrated plan to improve safety and involve changes in plant operation and design. These changes in tenns of expenditure of effort and its influence on the pace of returning the unit to service represent a significant category of activities that would be required prior to unit operation.
NRC Review and Hearing In addition to review and possibly fonnal approval of any p'an sub-mitted by the utility for returning the unit to service the NRC would, because of the unique regulatory concerns and based on the precedent established during the cleanup activities, be intimately involved in review and approval of all phases of activity.
The utility would be required to submit extensive documentation in support of relicen-sing. The NRC would conduct a safety and environmental review, although the scope of such a review cannot be precisely detennined at this time, given the unique circumstances associated with TMI-2.
I Such a review might entail a hearing which could be lengthy.
PROFESSIONAL QUALIFICATIONS OF DR. BERNARD J. SNYDER I am currently the Director, Three Mile Island Program Office, U. S. Nuclear Regulatory Commission.
I have been the Director of this office since April 1980.
I have overall responsibility within the NRC for the regulatory over-sight and approval of all activities associated with the utility's efforts to clean up Unit 2 of the Three Mile Island Nuclear Station (TMI-2) damaged in the March 28, 1979 accident.
I currently have a staff of 15 professionals located both at NRC Headquarters in the Washington, D.C. area and at the TMI-2 Site.
Prior to my current position, I was Assistant Director for Policy Review in the Policy Evaluation Office of the NRC Commissioners for 4 years.
In that capacity I directed or prepared studies of major technical and policy issues as advice to the Commissioners.
Areas included in studies were:
lessons learned from the TMI-2 accident, nuclear safeguards and security, nuclear exports, fire protection and qualification of safety equipment for nuclear facilities.
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Prior to the formation of NRC, I was with the U. S. Atomic Energy Comnission for 9h years.
I was involved in the management of a number of fast breeder reactor programs including the Clinch River Breeder and as Assistant Manager of the Fast Flux Testing Facility.
I was also the Project Manager for the l
decommissioning and decontamination of the government's Hallam Nuclear Power Facility, the first large nuclear power plant deactivated in the U. S.
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. From 1958 to 1962, I was a naval officer, assigned as a nuclear engineer on the staff of the Naval Reactors Program under Admiral Rickover. My primary responsibilities included involvement in the management of nuclear sub-marine development programs and management of the nuclear surface ship systems design program.
I received my Ph.D. in Nuclear Engineering from the University of Michigan in 1965 and my Masters and Bachelors Degrees in fiechanical Engineering in 1958 from Cornell University.
I am a member of Sigma Xi and Tau Beta Pt.
I I am the author of over 15 papers in the areas of radiation detectors, nuclear weapons proliferation, public perception of risk from nuclear plants and regulatory aspects of decontamination of radioactive facilities.
I am a member of the Steering Committee for the Technical Assessment and Advisory Group for the TMI-2 Cleanup.
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