ML20090H683

Forwards Rev 3 to Saxton Nuclear Facility Final Release Survey of Reactor Support Bldg Rept. Rev Prompted as Result of 920203 Meeting W/Snec & NRC

ML20090H683
Person / Time
Site:	Saxton File:GPU Nuclear icon.png
Issue date:	03/06/1992
From:	Hildebrand J GENERAL PUBLIC UTILITIES CORP., SAXTON NUCLEAR EXPERIMENTAL CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
C301-92-0007, C301-92-7, SNEC-92-0008, SNEC-92-8, NUDOCS 9203160207
Download: ML20090H683 (50)

Text

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i SAXTUN NUCLEAR EXPERIMENTAL CORPORATION ME GENERAL PUBLIC UTILITIES SYSTEM sNEC ,lerS?y Central Power & LJght Company Pennsylvanit. Electric Company PE JC Metropolitan Edison Company MAILING ADDRESS:

1 Upper Pond Road Parsippany, NJ WO54 March 5, 1992 C301-9%-0007 SNEC-92-0009 U. S. Nuclear Regulatory Commission Att: Document Control Desk Washington, DC 20555 Gentlemen:

Saxton Nuclear facility Operating License No. DPR-4 Docket No. 50-146 Final Release Survey of the Reactor Support Buildings Report. Revision No. 3 Enclosed for your use is Revision No. 3 to the subject report. This revision was prompted as a result of the February 3,1992 meeting between SNEC and the NRC. The revision includes discussions about controls that will be in place to prevent intermixing of the concrete rubble with soil and the use of clean fill from offsite to fill void areas among the concrete rubble in the RWDF basement and yard pipe tunnel.

The following changes should be made to your copy of the subject survey report:

1. Remove and replace the binder cover page.

2. Remove and replace the title page.

3. Remove and replace the Executive Summary (pages 1 through 5). "

4. Remove and replace Appendix F (pages 674 through 700).

5. Remove and replace Appendix G (pages 701 through 706).

6. Remove and replace Attachment 2, Plan of Action to Disposition the Filled Drum Storage Bunker, y

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. C301-92-0007-SNEC-92-0008 Please contact us if you require additional information.

Sincerely, M

J. E. Hildebrand President, SNEC JEH/EP/ pip Attachments cc: A. Adams - NRC R. Bores - NRC M. Reilly - Comonwealth of PA J. Roth - NRC

3. Weiss - NRC J

l Saxton Nuclear Experimental Facility ME PE bb JC Final Release Survey of the Reactor Support Buildings Rev. 3 , March 1992

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FINAL RELEASE SURVEY REPORT OF THE CONTROL AND AUXILIARY BUILDING, RADIOACTIVE WASTE DISPOSAL FACILITY REFUELING WATER STORAGE TANK, YARD PIPE TUNNEL, AND FILLED DRUM STORAGE DUNKER FOR THE SAXTON NUCLEAR EXPERIMENTAL FACILITY NRC LICENSE NO. DPR-4

-Prepared by GPU-Nuclear Corporation for the Saxton Nuclear Experimental Corporation (SNEC)

Revision 3, March, 1992

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EXECUTIVE

SUMMARY

The Saxton Nuclear Experimental Facility is a deactivated 20 megawatt thermal (20 MWt) pressurizeo water reactor (PWR). It is '

owned by the Saxton Nuclear Experimental Corporation (SNEC) and maintained- by GPU Nuclear Corporation (GPUNC) . The Saxton reactor facility is maintained under Title 10 Part 50 and Title 10 Part 30 Licenses, and Technical Specifications (Ref.1) . The licenses were .

amended t.o possess but not operate the Saxton reactor. The license expires on February 11, 2000 or upon expiration of the SNEC corporate charter, whichever occurs first.

The facility was built from 1960 to 1962 and operated from 1962 to 1972 primarily as a research and training reactor. The fuel was removed from the Containment Vessel (CV) ir 1972 and shipped to the Atomic Energy Commis.sion (AEC) f acility at Savannah River, S.C.  ;

Following fuel removal, equipment, tanks, and piping. located outside the CV were removed. The buildings and structures that supported reactor operations were partially decontaminated in 1972

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through 1974. The radiological condition of the f acility following shutdown was documented in a report titled " Decommissioned Status of.the-Saxton Reactor Facility" forwarded to the United States Nuclear-Regulatory Commission _(USNPC) on February 20, 1975-(Ref.

-2).

The _overall strategy to complete the decommissioning of .the f acility .and to release the site - f or -unrestricted use is a ,

multiyear, multiphased effort. The three principal phases are-as.

follows:

o- Removal of groundwater from the-- basement of the Radioactive Waste Disposal Facility and-yard pipe tunnel o Decontamination, survey,- and dismantlement of the reactor support structures or outbuildings

o Decontamination, survey, and dismantlement of the Containment Vessel and restoration of the site The first phase, groundwater removal, was completed in 1987. The decontamination and survey of the reactor support structures was completed in 1989 and are the subject of this report. The final phase, decommissionj ng of the Containment Vessel and restoration of the site is expected to be initiated within the next several years.

A cost estimate to complete the decommissioning of the Containment Vessel-was submitted to the USNRC in July, 1990 (Ref. 3).

A Technical Specification Change Request (TSCR) (Ref. 4) was submitted to the USNRC on September 22, 1987 with Rev. 1 submitted February 25, 1988 (Ref. 5) to remove the reactor suppo'rt

,. structures / buildings, including the Control and Auxiliary Building (C&A), Radioactive Waste Disposal Facility (RWDF), yard pipe tunnel, Filled Drum Storage Bunker (FDSB), and the Refueling Water Storage Tank (RWF.T) from Technical Specification Controls as a prerequisite for demolition. This report is being submitted in support of this TSCR. It documents that the reactor support structures / buildings have been decontaminated to USNRC guidelines for unrestricted use.

Decontamination was performed in 1987, 1988, and 1989 on the C&A building, the RWDF building, Lnc the_ yard pipe tunnel to ensure residual ~ contamination .was aF ?OW BS COasonably achievable. .A comprehensive final release survey of-these structures / buildings was conducted from October 1988 to June 1989 to verify that residual contamination was within USNRC guidelines for unrestricted Luse. The RWST.was shipped offsite as Low Specific Activity (LSA) radwaste to a contractor for decontamination and final offsite disposal. The tank concrete pad remains onsite an: was. included in this final release survey. The FDSB is an earthen unit with wooden

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cribbing. The top 6 to 12 inches of surficial materials were removed and shipped offaite as LSA radwaste for disposal at a licensed facility. After issuance of the TSCR, the FDSB will be dismantled and the wooden cribbing will be surveyed in accordance with procedures for survey and release of equipment.

The-final release survey plan for the reactor support structures was developed based on guidance from NUREG-2082, " Monitoring for Compliance with Decommissioning Termination Survey Criteria" (Ref.

6). The plan incorporated quality assurance (QA) into all phases of the survey process. The survey design involved dividing the building surfaces into 1 square meter grids. Survey measurements in each grid included alpha and beta gamma count rates, gamma exposure rates, and removable activity. Special surveys of pipes, conduits, holes, expansion joints, and ceiling supports were also conducted. All survey measurements were referenced to survey maps showing the grid locations for each area / cubicle.

Survey results were compared USNRC guidelines for unrestricted use. Surface contaminati. measurements were compared to Regulatory Guide 1.86, "Ter nation of Operating Licenses for Nuclear Reactors" (Ref. 7). Additionally, radiation levels were compared to guidelines outlined in References 8, 12, and 13.

Much ef fort was expended to perform a thorough and accurate survey.

Over 11,000 person-hours of Radiological Controls technician tJme were utilized during the survey. Oversight of the survey was provided by GPUNC supervision and management. Independent surveys

- were performed by QA personnel. Approximately 5000 one meter-squared grids were curveyed resulting in over 60,000 survey measurements. Special surveys were performed in approximately 1300 grids resulting in at least an additional 8600 survey measurements.

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The survey resulte show that the residual radioactivity is less than the USNRC guidelines for unrestricted use. In fact, decontamination and survey of forts woro designed to excood minimum regulatory guidance and standards whenever lower limits were reasonably achievable. Several areas woro identified that were inaccessible during this final release survey. These areas will be surveyed and dispositioned during dismantiomont and demolition.

Demolition hold points have beer identifiod to allow those additional surveys to occur. The USNRC will bo notified of the status of each hold point. If the hold point moots UStiRC releano guidelines, the USNFC will be given the option to review the survey results before final dinposition. If the hold point is datormined to be redwasto, it will be disposed of in accordance with procedures for radwasto Domolition hold points have also baon identif j ed for soveral electrical conduits and pipes that cont.ain residual radioactivity abovo USliRC gttidolines. They will be removed during demolition and disposed of as radwasto even though an ovaluation showed they would not be a sourco of radiation exposure to the public.

Survey documentation is thorough arid complete and available for USNRC insportion. All decontamination and survey tasks were accor plished with no adverse offect on the environment or the healt.h and sefecy of the public and the workors.

Upon issuance of the TSCR by the U5NRC, the C&A, RWDF, and FDSB will be dismantled and demolished. The SNEC area f ence will rert.ain in place. The concreto rubble from the buildings will be used as ,

backfill in the RWDF basement and the yard pipe tunnel.

An environmental pathways analysis was performed to derive concentration limits for residual radioactivity in the soil which would equato to an annual dose. TN standard models used to

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s calcelate the done require input assumptions and parameters such as a person residing at the site and consuming substantial quantitles of foot and wa.et taken from the site. This type of scenario is highly unlikely and provides a conservat1>e overestimat.e of doses that would actually occur.

Soil mater!als underneath the buildings that will intermix with the concrete rubble were analyzed f or residual radioactivity. Basud on the conservativo dose calculation methodology described, the soil would contribute less than 1 millirem per year to a maximally exposed individual. The soil immediately surrcunding the buildings

, was also sampled and analyzed. Measures will be taken during demolition of the outbuildings to prevent soil that does not satisfy the environmental pathways analysis guidelines from interm! xing with the concrete rubble. Clean fill f rom of f site will be used to fill void areas among the concrete rubble in the RWDF basement and yard pipe tunnel.

A final environmental pathways analysis will be performed at the time of final site closure to ensure that residual radioactivity in materials (soil and concrete rubble) remaining at the site will comply with the dose limit criterion of 10 millirems per year when the site is releaFed for unrestricted UEe.

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9 APPENDIX F ENVIRONMENTAL PATllWAYS ANALYSES 1

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INTRODUCTION i An environmental pathways analysis was performod to derivo f concentration limits for the soil which would equate to an annual l doso limit. Fodoral guido11nes for residual radioactivity in soil '

have not yet boon promulgatt J. In the interim, critoria are

, developed on a site-specific basis using published environmental doso calculation methodologies. Published data (Ref. 8, 18, and -

31) and correspondence from the U$NRC to SNEC (Ref. 32) suggests  !

that 10 mrom por year above background is an acceptable doso limit [

critoria for unrestricted roloano of the sito. A final l

onvironmental pathways analysis will be performed at the timo of final site closure to ensure that residual radioactivity in materials (soil and concreto rubble) romaining at the site will  !

comply with the doso limit for unrostricted release.

For calculation purposes, a dose of 5 mrom por year from all pathways was used to derive limits on soil radionuclide j concentrations. A nimple linear multiplication can be used to t calculato dosos for actual soil samplo concentrations because  :

linear chain models woro used in the calculations. For examplo, if  !

5 mrem / year. equates to 5 pC1/gm of Cs-137, then 10 mrem /yoar j equates to'10 pC1/gm Cs-137. For thoso radionuclidos which occur ,

in the environment as a result of prior atmospheric weapon testing, their background concentrations must be added to the derived limit

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concentrations. For examplo, appropriate background concentrations j for Cs-137 and St-90-is 1 pC1/gm (Ref. 33).

The standard models used to calculate the doses require input assumptions.and paramotors such as a person residing-at tho'aite and consuming substantial quantities of food and water taken from the site. This type of scenario is highly unlikely and providos a -

conservative (overestimato) of doses that would actaally occur.

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1)ackground The average person in the United States receives about 300 mrom per year from natural background radiation sources. This includes contributions from cosmic, terrestrial, and internal radiation exposures. Radon gas in the home is the largest component of natural background and is estimated to produce an averace annual dose of about 2300 mrom to the lung. This lung dose is considered to be equivalent to a whole body dose of 200 mrem (Ref. 23).

Dose rates from external radiation sources were measured at a number of locations in the vicinity of StiEC using thermoluminescent dosimeters (TLDs), fiaturally occurring sources, including radiation of cosmic origin and natural radioactive materials in the air and ground, as well as fallout from prior nuclear weapon testing, resulted in an average of 75 mrom per year being recorded at the monitoring locations. Soil samples collected in the vicinity contain low levels of Cs-137 as a result of prior atmospheric nuclear weapon testing. (See Appendix E for background soil results.) The StiEC soil materials which will be backtilled into the RWDF basement and yard pipe tunnel would contribute a very small additional increment to the normal radiation that people living in the ShEC vicinity already receive from environmental sources.

Exposure Scenarios:

An evaluation of doses to members of the public was performed for three scenarios: 1) abandonment of the site after 30 years and subsequent residential and agricultural use (the intruder scenario), 2) retention of the site with immediate construction of now office space (incidental-occupation scenario), and 3) flooding in the Raystown Branch of the Juniata River scours some soil into the river with subsequent exposure through the fish pathway (flood-fish scenario).

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The ovaluation of dosos was performed for each potential radionuclido of interest in the soil. The dose calculations for

.the scenarios are complex and include both oxternal exposura due to direct radiation shine from radionuclidos in the soll and internal expbsure ' rom Angostion and inhalation. Differences in physiology, metabolism, and dietary habits for individual age groups are also considered. The most limiting dosos woro relected from each pathway f or each scenario, that is the age group and critical organ which yield the highest dono. For examplo, the highest doso for Sr-90 in the rilk pathway may be from the infant bone whereas in the groundwater pathway it may be from the toen bono.

Attachment 1 provides a brief description of the dose calculation methodology without decay correction, using exposure of an adult to Co-60 an an example. The methods used are consistent with thoso given in References 1 to 4 and 14.

Intruder Scenario:

The intruder scenario assumos that the company retains control of the site for 30 years. Since the site is currently used by a Ponoloc line department, and the sito contains an important power grid interconnection, the 30 year estimate for continued site control is reasonable. The Army Corps of Engineers has a flowage easement on the floodplain of the site, and thoro is a Liberty Township ordinance that prevents building in the floodplain area.

The Commonwealth of Pennsylvania also rostricts construction in floodplain areas (Ref. 9). These ordinances make residential or offico development unlikely.

Despite the low probability of occurrence, an intruder family lu assumed to erect a home, grow a garden, drill a well, and tend livestock on the site. The livostock includes at least a milk cow and a beef steer. The pathways evaluated for the resident intruder family aros direct radiation both outside and insido the home, inhalation of resuspended dust both outside and inside the home,

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drinking well water, eating homegrown vegetables, drjnking raw home-produced cow milk, and eating home-produced beef.

Environmental dose assessment methodology is described in Attachment 1.

The direct radiation dose is evaluated for both time spent inside and outside the house. The dose rate outside the house was evaluated by estimating the dose at the conter of the top face of a large disk source one foot (30 cm) thick. The dose rate inside the house is based on a more comt. lex geometry. Since the source is the soils surrounding the house, the modeled geometry is a large disk source with a house sized hole in the center. The dose rate at the center of-this hole represents the dose rate at the center of the house. Since the actual dose rate will vary from this minimum value at the center, to a larger value at the edge (exterior wall) an adjustment must be made to account for this.

Since the dose rate at the edge of a large area source is just one-half of the dose rate at the center, the dose rate at the exterior wall of the house can be assumed to be 6ne-half of the dose rate outside the home. This exterior wall dose and the dose at the center are averaged to obtain an average dose rate for the interior of the house. An additional factor of one-half was then applied to account for the shielding provided by the construction materials of the house. Adults, teenagers, and infants were assumed to spend 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> inside the house and two hours outside the house per day. Children were assumed to spend 12 inside and six hours outside per day. The remaining six or 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> are aesumed to represent time not at home.

The vegetation, cow milk, and meat pathways are treated essentially as presented in Ref. 1. Stable element transfer coefficients are used to estimate the activity in the vegetation. This is then used for the vegetation pcthway as well as for feed to the milk and meat animals. One-half of the usage factors in Table E-4 of Ref. 1 (average individual) are used for the consumption rates since this is a more-reasonable assumption.

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For the inhalation pathway, the radioactivity inhaled depends on the amount of timo spent indoors and outdoors at home. The soil is assumed to be rosuspended at the rato given in Ref. 2 for the northeast. This valuo is used to e s t i r..a t o the radioactivity inhaled while outdoors. One-half of this concontrat. ion is assumed to be continuously present indoors. Inhalation rates given in Ref.

1 are used and applied to each of the two different concentrations based on the amount of time spent in each location.

The groundwater ingostion pathway requires estimates of the amount of r6 _oactivity in the water as a result of contact with the deep (below 10 feet, near surface soi. tre above 10 foot) soil.

Equilibrium transf er coef ficients f rom Ref erences 3 and 4 are used tu estimate the concentrations in the water. An annual ingestion quantity of liquids is estimated based on Referenco 1 and Ref erence

5. It was assumed that 33 percent of the total com's from well water at home. This is a reasonable assumption bouume of the consumption of milk and bottled products. No irrigation of vegetation f rom well water is assumed. Since the pathway from well water is independent of the surface soil concentrations, different limits have been developed for the doop soil concentrations associateo with the groundwater pathway.

The results of the evaluation of the intruder scenario are shown below. These results pertain to this econario only. Other scenarios may yield more restrictive results. The limits based on the combination of all scenarios are given in the summary. The no decay limit applies to the case where the Company immediately loses control of the site following demolition and backfilling of the site. It is not considered to be a likely scenario and is included only for comparison.

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INTRUDER SCENARIO - RADIONUCLIDE CONCENTRATION LIMITS FOR NEAR SURFACE SOILS

• LIMIT NO DECAY LIMIT 30 YR. DECAY RAD 7.ONUCLIDE (pCi/qm) (DCi/cm)

Co-60 0.56 29 Sr-90 0.17 0.35 (s-134 0.66 16000 Cs-137 2.1 4.2

• Note: Using assumptions and parameters discussed above, each individual radionuclide concentration in soil will yield a dose of 5 mrom/ year.

INTRUDER SCENARIO - RADIONUCLIDE CONCENTRATION LIMITS FOR DEEP SOILS

• LIMIT NO DECAY LIMIT 30 YR. DECAY R ADI ONUCLI_D_E, (pci/cm) (DCi/cm) >

Co-60 1000 53000 Sr-90 0.96 2.0 Cs-134 51 1.2E6 Cs-137 58 120

• Notet Using assumptions and parameters discussed above, each individual radionuclide concentration in soil will yield a dose of 5 mrem / year.

Incidental-Occupation Scenario:

The incidental-occupation scenario assumes that the Company retains control of the site following dismantlement and demolition and installs an office building on the site shortly thereafter. At least one person is assumed to work in the building for the normal 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> per year. The pathways important for this scenario are s

the groundwater pathway, inhalation pathway, and direct radiation pathway. Since there is no decay associated wAth this scenario,

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l the groundwater doses for the incidental-occupation scenario will be the same as those for the intruder scenario except that the individual in this case ingestu only one-half as much groundwater from the site as a resident intruder would.

For the direct exposure pathway, no exposure outside the building is considered. The maximum exposed inctiviriual therefore spends 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> inside the building exposed to tbs source outside. This is similar to the indoor portion of the dire':t exposure pathway in the intruder scenario. In this scenario, only exposure of working-age adults was considered. For the inhalation pathway, the indoor method used in the intruder scenario applies. In this case, the worker was assumed to inhale 33 perceni. of tite total annual air volume while at work, even though 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> is only 25 percent of a year. This is appropriate since breathing rate and volume are expected to be slightly above average during work.

INCIDENTAL-OCCUPATION SCENARIO - RADIONUCLIDE CONCENTRATION LIMITS FOR NEAR SURFACE SOILS

• LIMIT RADIONUCLIDE gg/g ,

Co-60 S.6 Sr-90 1200 Cs-134 6.9 Cs-137 28

• Note: Using assuinptions and parameters discussed above, each individual radionuclide cor. centration in. soil will yield a dose of 5 mrem / year.

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INCIDENTAL-OCCUPATION SCENARIO - RADIONUCLIDE CONCENTRATION LIMITS FOR DEEP SOILS

• LIMIT

_RADIONUCLIDE (pCi/cm)

Co-60 2000 Sr-90 3.1 Cs-134 330 Cs-137 450

• Note: Using assumptions and parameters discussed above, each individual radionuclide concentration in soil will yield a dose of 5 mrom/ year.

Flood-Fish Scenarios In the flood-fish scenario, a flood is assumed to remove the top 10 centimeters of a 100 meter by 100 meter area of the soil and deposit it in a small length of the river bottom. This volume is approximately 1200 metric tons. Following redeposition in the river, 100 percent of the radioactivity in the entire mass of the redeposited soil (sediment) is assumed to be leached from the sediment in one year. This is extremely conservative, since in actuality, deposition of activity into sediments is normal for liquid effluents. Also the surficial material which contains the cesium activity in much of the area has resisted attempts to remove the cesium even by vigorous chemical attack'(Ref. 26). For the flood-fish scenario, the derived soil concentrations exceed the criteria listed for the intruder and incidental-occupation scenarios by a f actor of 100 to 10,000. The flood-fish pathway, therefore is considered too unrealistic for selecting criteria for the soil. The calculated soll concentrations for the flood-fish scenario are listed below.

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FLOOD-FISH SCENARIO - RADIONUCLIDE CONCENTRATION LIMITS j FOR NEAR SURFACE SOILS LIMIT RADIONUCLIDE (pCi/cm) i Co-60 8.2E4 Sr-90 730 i Cs-134 550 Cs-137 750 Summary:

Since the soll concentration limits provided previously are based on a dose limit of 5 mrem / year, rather than on any actual soil, soil will' be characterized to determine the actual radionuclide content. Only four radionuclides most likely to be detected above environmental levels have been evaluated.

lo11owing the charactorization, the soils which can be used as backfill will be determined based on the concentration limits in this submittal. Soils containing mixtures of radionuclides will be considered to be qualified if the sum of the concentration of each radionuclide divided by its limit does not exceed one (similar to a total MPC calculation, see 10 CFR 20). For example, if radionuclides A, B, and C are present in concentrations Cs, Cb, and Cc, and if the applicable soJ ' limit concentrations are La, Lb, and Lc, respectively, then the concentrations will be limited so that the following relationship exists:

(Ca/La) + (Cb/Lb) + (Cc/Lc) 1 1 w

The radionuclide concentration limits provided are average scil concentration limits. Small area variations above and below these limits can be averaged out provided the averaging area does not cause a failure of one of the assumptions in the evaluation. .

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t The actual soil concentration limit will be the lower of the values derived for each of the three scenarios; the 30 year decay intruder; the no decay incident. ally exposed worker; or the flood-fish ingestion. The table below lists the required radionuclide concentration limits selected from each scenario. The concentration limits should be added to the background concentrations.

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LIMITS FOR NEAR SURFACE SOILS LIMIT RADIONUCLIDE (pCi/cm) DASIS (above background) (Exposure Pathway-Scenario)

Co-60 5.6 Direct-occupational I Sr-90 0.35 Vegetation-intruder -

Cs-134 6.9 Direct-occupational Cs-137 4.2 Direct-intruder LIMITS FOR DEEP SOILS

• LIMIT RADIONUCLIDE (pC1/qml ,

BASIS (above background) (Scenario)

Co-60 2000 Occupational Sr-90 2.0 Intruder Cs-134 330 Occupational Cs-137 120 Intruder

• NOTE: Limits for deep soils are based on groundwater-pathway.

Conclusions:

Soil materials containing residual radioactivity can_romain at the [

site without any adverse impact on human health and the environment if conducted as described. .The standard dose calculation models contain conservative input parameters and assumptions to ensure that the actual. dose in any of the scenarios evaluated will not exceed the annual dose limit. Examples of a few of the conservative assumptions are

1. ). The assumption that occupancy actually occurs in a flood plain area that will remain under the control of an electric utility.

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1 2.) The fact that Cs-137 and Co-60 are so strongly bonded to the  !

l local surficial materials as to make them chemically unavailable for environmental pathway mobill::ation and  ;

. subsequent human uptake, i I

3.) The assumption that vegetables, milk cows, meat steers, and l well water are all produced from the less than 50,000 square feet in question.  ;

4.) Critical organ doses were calculated and applied to the annual dose limit.

5.) The f act that a soll cap will be used and the site revegetated was not included in the calculations.

Given-the small doses for the maximally exposed individual, the limited total population, and the small probability of the scenarios, no adverse health effects could reasonably be expected.

The limiting concontration for each radionuclide is selected as the lowest from any of the-three scenarios evaluated. Since both the intruder scenario and the flood-fish scenario are already actually the worst case accidental exposure conditions and represent the only_ reasonable unusual circumstances, no additional impacts could be expected from hypothetical accioental exposures.

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. REFERENCES

1. Regulatory Guide 1.109 " Calculation of Annual Doses to Man From Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR 50, Appendix I" USNRC Oct. 1977.

2. NUREG/CR3585 "De Minimus Waste Impacts Methodology".

3. "A Simplified Pathway Analysis Approach for Establishing '

Limits for Soil Contamination", Till, ot. al. from Health

• Physics Considerations in D&D, Proceeding of the 19th Topical Symposium of the Health Physics Society.

4. NUREG/CR3332 " Radiological Assessment", Till and Meyer.

5. "The Health Physics and Radiological Health Handbook",

Nucleon Lecterst Associates.

6. Branch Technical Position, USNRC Radiological Assessment Branch Environmental Monitoring Technical Specifications, Rev. 1, Nov. 1979.

7. " Environmental Development Plan -

D&D", USDOE 1978,

. DOS /EDP0028. ,

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8. NUREG/CR4289 " Residual Radionuclido Contamination Within '

and Around Commercial Nuclear Power Plants".

9. 25 PA 106 " Flood Plain Management", Pennsylvania Administrative Code Chapter 25, Section 106.

10. SAND 84-0036.TTC - 0470 "RADTRAN III" Sandia Laboratories, Feb. 1986.

11. "U.S. DOE Guidelines for Residual Radioactive Material at Formerly Utilized Sites Remedial Action Program and Remote Surplus Facilities Management' Program Sites", (Revisjon 2, March 1987).

12. GP-R-211013 "A Gidde iar Obtaining Regulatory Approval to Dispose of Very Low Level Wastes from Nuclear Power Facilities by Alternate Means", March 1986.

13. "The Photon Shielding Manual", A. Foderaro.

14. NUREG 1101, Vol. 1 "Onsite Disposal of Radioactive Waste",

March 1906.

15. NUREG/CR2082 " Monitoring for Compliance with Decommissioning Termination Survey criteria", Holoway, et.

al., June 1981.

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16. PNL3852 "A Method for Determining ' Allowable Residual -

Contamination Levels' of Radionuclides in Soil", D. A.

j Napier, May 1982.

17. PNLS801 " Allowable Residual Contamination Levels in Soil '

for Decommissioning the Shippingsport Atomic Power Station Site", Kennedy, Napier, & Soldat, September 1983.

18. NUREG 0506 " Final Generic Environnental Impact Statement on '

Decommissioning of Nuclear Facilities", August 1988.

19. NUREG 0613 " Residual Radioactivity Limits for '

Decommissioning" Draft Report E. Conti, Oct. 1979.

20. NUREG 0707 "A Methodology for Calculating Residual Radioactivity Levels Following Decommissioning", Eckerman and Young, October 1980. t

21. " Establishment of Criteria for Unconditional Release of the  !

Shippingsport Atomic Power Station Site", Eyer, et. al.,

1987 International Decommissioning Symposium CONF 871618.

t

22. NCRP 91 " Recommendations on Limits for Exposure to Ionizing Radiation", June 1987.

23. NCRP 93 " Ionizing Radiation Exposure of the Population of the United States", Sept. 1987.

24. BEIR 1980 "The Effects on Populations of Exposure to Low Levels of Ionizing Radiation", National Academy of f Sciences, Aug. 1980.

25. GPU Letter C301-88-2017 "SNEC Radiological and Environmental Monitoring Program 1982 through 1987", Aug.

1988,

26. " Geologic, Chemical, Radiometric and Geotechnical Studies of Samples from Eleven Drillholes in Surticial haterials, '

Saxton Nuclear Facility, Saxton Pennsylvania", A. W. Rose-et. al., Pennsylvania State University, December 1988. *

27. " Application to the U.S. Atomic Energy Commissjon for -

Reactor Construction Permit and Operating License, Final Safeguards Report", Saxton Nuclear Experimental  ;

4 Corporation, April 1961.

28. " Application to the U.S. Atomic Energy Commission for Reactor- Construction Permit and Operating License, q Preliminary Hazards Summary Report", -Saxton Nuclear Experimental Corporation.

29. " Policy Statement on Radioactive Waste Below Regulatory Concern", USNRC, Ju.ly 1986.

- 688 -

-w.,-, .-y.,. , e-pg.-v--, ,-r , . , , , + y,, r m y -.,,,m, ,y -

yry,w-, y,-,,y,-

A.

30. " Residual Activity Limit for Decommissioning", pp. 411-420 in " Decontamination and Decommissioning of Nuclear Facilities", M. Osterhout ed., September 1979.

31. Draft Hegulatory Guide Task DG-1005, " Standard Format and Content f or Decommissioning Plans for Nuclear Reactors",

USNRC, September 1985.

32. Letter dr.ted February 9, 1988 to R. W. Howard, Jr.,

President SNEC,

Subject:

NRC Review of Technical Specifications Amendment Application, from USNRC Alexander Adams, Jr., Project Manager Standardization and Non-Power Reactor Project Directorate.

33. " Handbook or Radioactivity Measurements Procedures", NCRP Report No. 58, Second Edition, 1985.

4 D

o

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T d

ATTACHMENT 1 TO APPENDIX F DOSE CALCULATION METHODOLOGY INTRODUCTION The purpose of this Attachment is to illustrate the methods used to calculate the doses resulting from the various environmental ,

exposure scenarios described earlier. Generally a scenario will result in both external exposure due to direct radiation shine from residual radionuclides in the soil and internal exposure from ingestion of a fraction of the same radionuclides. Since the intention is to calculate doses due to radionuclidos which have resulted from operation of the SNEC reactor, dose contributions f rom naturally occurring radionuclides and from other activities such as atmospheric nuclear weapon testing are not included.

Cesium-137-is the only radionuclide routinely found in the soil at the Saxton site which originates from both reactor operations and weapons fallout. Dose calculations will be based upon soll radionuclido concentrations over and above this fallout background increment.

In general terms, the equation for computing a direct radiation dose from_ residual radionuclides in soil _ist D E** = R,

• t, + R 3 't 3 yr where R, t, = product of dose rate outside (mR/hr) times time spent outdoors (hrs /yr)

R t3= product of dose rate indoors (mR/hr) times time spent 3

indocrs (hrs /yr)

A given scenario may postulate only one or both of the terms in the equation above. Also the assumed values for T 3and T, will dif fer from one scenario to another. The indoor and outdoor dose rates

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i must be calculated from an assumed size and geometric shape of the radiation source, i.e., soil containing residual radioactivity.

A generalized form of the equation for computing the dose from j ingestion of radionuclidas may be written as D ES = C,

• T

• K ' V

• U ' DCF yt where C, a radionuclide concentration in soil, pC1/gm T = transfer coefficient such as soil to air transfer (resuspension), soll to plant or soil to watertransfer.

The units of T will depend on the media involved.

i K = bioaccumulation or biological transfer coefficient, which accounts for transfer of ingested radionuclides from food or water to animal flesh or milk. Usually this is a dimensionless number or fraction.

V = mass or volume of food / water ingested annually by an animal. [If a particular pathway does not involve transfer of radionuclides from animal to man, this factor may be set equal to one.)

U = annual usage factor for humans, such as liter / year of water consumed, Kg/ year of meat or vegetables consumed or cubic meters per year of air inhaled.

DCF = dose conversion factor in units of mrem /pC1 ingested.

Dose conversion f actors (DCF) are compiled in the literature. The values used in this analysis were mainly obtained from Ref. 1.

Since the absorbed dose depends upon many factors such as energy and type of radiation emitted, organ effected, age of the exposed individual, etc. the DCF's are compiled by radionuclide for each age group and each organ. To perform a complete dose assessment, you must sum the doses f rom each -radionuclide and you must- sum over all exposure pathways relevant to a particular scenario. For example, if three radionuclides were present in the soll, and the scenario of interest involved direct exposure, air inhalation and l - 691 -

l^

d consumption of water and vegetation (4 exposure pathways), the total dose would be a sum of, twelve terms (3 radionuclide doses for each of four pathways). Furthermore this computation is repeated I

for four age groups (inf ant, child, teen and adult) to identify the most effected segment of the population.

Given below are the mathematical equations and the parameter values used to calculate the doses for the major exposure pathways.

Groundwater:

Groundwater ingestion dose is derived by estimating the concentration of radionuclide in the water and then applying an annual consumption quantity. This is accomplished by multiplying the concentration of radionuclide in the soil by a soll/ water transfer coef ficient (Kd) to obtain the water concentration. Usage f actors based on reference man and RG 1.109 are used. For example, Reference 3 provides a Kd for cobalt-60 of 1600 ml/g. For a 1 pC1/g soil concentration ( [C] ) the estimated water concentration ( [Cw) ) is:

[Cw) = 1000 ml/L * [C] pC1/gm / Kd ml/g or,

[Cw] = 1000

• 1 / 1600 = 0.6 pC1/L Appendix F reference 5 gives usage f actors for adults derived from ICRP 23. A 1 to 1 to I ratio of usage of groundwater, milk, and purchased fluids is assumed for the intruder scenario. For the incidental-occupation scenario it is assumed .that 50% of the groundwater an individual ingest is ingested at work. The ratios between the age groups in RG 1.109 are used to define the usage in the other age groups-based on'the reference man. This results in total usages:as listed below:

Adult: 205 L/yr Child, Tecn 145 L/yr Infant: 140 L/yr

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. - . . . _ _ . . _ . _ _ . . _ _ _ . _ _ . ~ __ _____ _. . . - _ - - - . __

s Annual ingestion quantity is then the annual ingestion volume V times the derived concentration, using the adult and Co-60 as an example:

0 = V L/yr * [Cw)pci/b or, 0 = 205

• 0.6 = 123 pC1/yr The dose to the individual is then the Dose Conversion Factor [DCP) ,

in mrem /pci times the ingested activity:

D mrem /yr = [DCF) mrem /pc1

• O pC1/yr or, for adult Co-60 D = 4.02E-5

• 123 = 4.94E-3 mrem /yr for 1 pCi/gm soil for the critical organ ,

, Vegetation:

Vegetation ingestion - dose is derived by estimating the concentration of radionuclide in the vegetation and then applying an annual consumption quantity. This is accomplished by multiplying the concentration of radionuclide in the soil by a soll/ vegetation transfer coef fielent (Div) (stable element transfer factors) to obtain the vegetation concentration similar to the estimation of groundwater activity. For a 1 pC1/g soil concentration ( [C] ) the estimated vegetation-concentration for cobalt-60 ( [Cv) ) is:

[Cv) = 1000 g/Kg

• Biv(pC1/gm of veg.-per pCi/gm soil)

• 1 pC1/g or,

[Cv) = 1000

• 9.4E-3

• 1 = 9.4 pC1/Kg Usage factors-based on Regulatory Guide 1.109 Table E-4 are used.

The -individual is assumed to obtain 50% of vegetables from the home garden. The annual ingestion amount ( H ) for an adult is therefore 95. Kg/yr. The annual ingestion activity is then the

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s concentration in the vegetation times the quantity of vegotation ingested Q pC1/yr = H Kg/yr * [Cv) pCi/Kg or, Q = 95

• 9.4 = 890 pC1/yr The dose to the individual is then the Dose Conversion Factor [DCF) in mrem /pc1 times the ingested activity:

D mrem /yr = [DCF) mrom/pCi

• Q pC1/yr .

or, for adult Co-60 D = 4.02E-5

• 090 = 3.58E-2 mrem //r for 1 pCi/gm soil for the critical organ Meats Heat ingestion dose is derived by estimating the concentration of radionuclide in the meat and then applying an annual consumption quantity and dose conversion factors. This is accomplished by first multiplying the concentration of radionuclide in the vegetation and water by animal consumption rates and transfer coefficients (Fm) to obtain the meat concentration [Cm). The groundwater [Cw) and vegetation [Cv) concentrations already derJ red as previously described are used to derive the activity ingested by the steer. Regulatory Guide 1.109 provides animal consumption rates as 50 L/d of water and 50 Kg/d of vegetation.

i

[Cm) pCi/Kg = [Cw) pC1/L

• 50 L/d

• Fm d/Kg + [CV)pCi/Kg

• 50 Kg/d

• Fm d/Kg or, for Co-60 (Cm) pC1/Kg = 0.6 pC1/L

• 50 L/d

• 1.3E-2 d/Kg + 9.4 pCi/Kg

• 50 Kg/d

• 1.3E-2 d/Kg = 3.4 pCi/Kg Age dependent consumption rates from RG 1.109 Table E-4 are used.

l l

l

- 694 -

l .

The individual is assumed to obtain 50% of meat from the home grown animal. The annual ingestion amount ( H ) for an adult is thoroforo 48 Kg/yr. The annual ingostion activity is then the concentration in the meat times the quantity of moat ingosted:

O pC1/yr = M Kg/yr * [Cm) pC1/Kg or, O = 48

• 3.4 a 160 pC1/yr The dose to the individual is then the Doso Conversion Factor [DCF) in mrom/pci timos the ingestod tvity:

D mrem /yr = [DCF) mrom/pC1

• Q pCityr or, for adult Co-60 D = 4.02E-5

• 160 = 6.43E-3 mrom/yr for 1 pC1/gm soil for the critical organ Milk:

Milk ingestion dose is derived in an almost identical manner to meat by estimating the concentration of radionuclido in the milk and then applying an annual consumption quantity and dose conversion factors. This is accomplished by first multiplying the concentration of radionuclido in the vogotation and water by animal consumption rates and transf er coef ficients (F1) to obtain the milk concentration [C1). The groundwater [Cw) and vogotation (Cv) concentrations already derived as previously described are used to derive the activity ingested by the milk cow. Regulatory Guido 1.109 provides animal consumption ratos as 60 L/d of water and 50 Kg/d of vogotation.

[C1) pCi/L = (Cw) pC1/L

• 60 L/d

• F1 d/L + [Cv) pCi/Kg

• 50 Kg/d

• F1 d/L or, for Co-60

[C1) pC1/Kg = 0.6 pC1/L

• 60L/d

• 1.0E-3 d/L + 9.4 pCi/Kg

• 50 Kg/d* 1.0E-3 d/L = 0.27 pC1/L

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l I

i i

As described in the section describing groundwater, Regulatory Guide 1.109 and reference man data are used to estimate the amount of milk ingested, assuming that 33% of all fluids ingested by the ,

l individual is milk and that all the milk ingested is produced at home. The annuni ingestion amount ( H ) for an adult is therefore 205 L/yr. The annual ingestion activity is then the concentration in the milk times the quantity of milk ingested:

O pCi/yr = M L/yr * [C1) pC1/L or, Q = 205

• 0.27 = 55 pCi/yr The dose to the individual is then the Dose Conversion factor [DCF) in mrom/pci times the ingested activity:

D mrom/yr = [DCF) mrem /pC1

• O pC1/yr or, for adult Co-60 D = 4.02E-5

• 55 = 2.21E-3 mrem /yr for 1 pC1/gm soil for the critical organ Inhalation:

Dose due to inhalation of resuspended particulates is -estimated by deriving an average air concentration multiplying -by the age dependent inhalation rates and a Dose Conversien Factor. This is accomplished by first estimating the resuspension of the soil. -

Reference 2 provides guidance that in the northeast an average airborne dust loading is about 0.258 mg/ cubic meter (m )3 . At a 1 pC1/g soil activity, the air concentration is then the soil activity times the air dust loading:

[Cao) = (1 pCi/g / 1000 mg/g)

• 0.250 mg/m = 2.58E-4 pC1/m 3 3 It is also assumed that the radionuclide air concentration inside a building (the home for the intruder or the office building-for l

l

- 696 -

l i

s the incidental-occupation scenarios) is one-half that outdoors as calculated above or:

[ Cal] = 1.79E-4 pCi/m 3 Age dependent inhalation rates are give in Table E-5 of Reference

1. These total annual inhalation volumes ( A m 3 /yr) are adjusted for the amount of time each age group is assumed to spend indoors (T1 hrs) at the site, outdoors at the site (To hrs), and not at the site. For example, the adult is assumed to spend 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> inside, 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> outside, and 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> not at home for i.he intruder. For the incidental-occupation scenario, the individual is assumed to inhale 3 31L of the total annual volume at work even though the normal 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> at work is only 25% of the time. For example, the annual air volumes (Vi m and Vo m ) for an adult at the site 2 3 are 3

'i Vi m /yr = Ti hrs /d / 24 hrs /d

• A m'/yr or, Vi = 12 hrs /d / 24 hrs /d

• 8000 m'/yr = 4000 m 3 /yr n

Vo m'/yr = To hrs /d / 24 hrs /d

• A m 3 /yr or, Vo =-2 hrs /d / 24 hrs /d

• 8000 m /yr = 670 m'/yr 3 The activity (A) inhaled each year is then the volume inside times the air concentration inside plus the volume outside times the air concentration outside:

A pC1/yr = Vo m) * [Cao) pCi/m + Vi m) 3 * [Cai) pCi/m 3 or, A = 670

• 2.58E-4 + 4000

• 1.29E-4 = 0.69 pCi/yr These total annual inhaled activities can then be multiplied by the inhalation dose conversion factor to obtain annual dose:

D mrem /yr = A pCi/yr

• DCP mrem /pCi 697 - l m -

. +

l For t is adult and cobalt-60 this would be:

Da 0.69

• 7.46E-4 = 5.15E-4 mrem /yr l

Direct Radiation l

Dose from direct radiation is estimated using the methodology in Reference 13. The source is assumed to be a 100-meter-diameter, 30-centimeter-thick cylinder of soil. An air shield 45 centimeters thick is used and the dose rate is evaluated at knee heigh;.

The same times spent at the site indoors and outdoors, as described in the section on inhalation doses, are used for the direct radiation doses. The dose rate outside is equivalent to that calculated from the 100 m diameter source (Do). The dose rate inside (D1) is derived by calculating a second dose rate using a 13-meter-diameter source to represent the area of a building. This result (Db) is subtracted - f rom the larger source dose rate to provide a dose representative of the center of an area inside the larger source that itself is not a source, i.e., a "no-source hole".

Since an individual in a building can be expected to move about, the average inside dose rate then would be the average of the dose at the center of the building and the dose rate at the edge. The dose rate at the edge of the "no-source hole" is taken as one-half of tha dose rate in the center of the large source, since this is a simple 2 pi to 1 pi geometry change.

A reduction-of this average of one-half is then taken to account for the shielding effect of building materials:

Di mrem /hr = (((Do - Db) + (Do / 2)) / 2) /2

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l

{.

l

For Co-60 the outsido dose rato (Do) for 1 pC1/g soil is 3.2E-3 mR/hr For Co-60 the building conter dose rato (Db) for 1 pCi/g soll is 3.0E-3 mR/hr.

The insido dolo rato is thereforo:

Di = (((3.2E 3.0E-3) + (3.2E-3 / 2)) / 2) /2 = 4 aE-4 mR/hr Doso to the individual (D) is then the insido dose rate times the timo spent indoors plus the outsido dose rato timos the timo spent outdoors. For example, as detailed in the inhalat.on section, an adult is assumod to spend two hours por day outsido and 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> per day insides D mrem /yr = (Do mR/hr

• 2 hrs /d + Di mR/hr

• 12 hrs /d)

• 365 d/yr

. or, D= (3.2E-3

• 2 + 4.5E-4

• 12)

• 365 = 4.3 mR/yr which is assumed to be equivalent to 4.3 mrom/yr.

Flood-Fish:

The dose from the flood-fish pathway is evaluated by assuming a portion of the surface soils is flushed into the river by a flood.

4 It is assumed that an area of 100 meters by 100 motors and 10 cm deep is removed and deposited in the river. This is a volume of 1.0E9 cubic centimeters (cc). Using a density of 1.2 grams por cc this is then a mass of 1.2E9 grams, or at 1 pCi/gm, a total of 1.2E9 pC1. {

The Raystown Branch of the Juniata River has an annual flow of 918 cubic feet por second which is equivalent to 8.2E11 L/yr. Assuming that all of the activity in the rodenosited soils is loact ed out of the soils into the river water in one year, this would result in

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.. . _ _. .. . _ _ . . . . _ - . _ . _ _ _ . _ . _ . ~ . . _ _ . _ _ - . - _ . _ . _ _ - _ . .

concentrations in the river water [Cr):

[Cr) pC1/L = 1.2E9 pC1 / 8.2E11 L = 1.5E-3 pC1/L The concentrations of radioactive materials in the fish can then be estimated by applying bioaccumulation factors given in Reference 1.

For example, the f actor (Bf) for cobalt-60 is 50 pCi/Kg in fish per ,

pC1/L in the water. The concar.tration in the fish [Cf] is therefore:

l l

[Cf) = Bf (pC1/Kg)/(pC1/L) * [Cr), pC1/L or,

[Cf) = 50

• 1.5E-3 = 0.075 pC1/Ng l I

The amount of radioactivity an .l individual would ingest is then this concentration in fish times t.he annual amount of fish a person

(

! woulo consume. Reference 1 provides age dependent annual ingestion quantities. For example, adults are expect 2d to eat as much as 21 Kg of freshwater fish each year. The total dose is then the concentration in the fish times the annual ingestion times the dose conversion factor for one year:

D= [Cf) pC1/Kg

• 21 Kg

• DCF mrem /pCi l nt, l

D = 0.075

• 21

• 4.02E-5 = 6.3E-5 mrem /yr for 1 pCi/g cobalt-60 in the soll.

I i

l l

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l l

l l

---

,.w-------- - - - - - ----.-- - - -

e i

APPENDIX G DISMANTLEMENT AND DEMOLITION PROCESS

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. . . _ . , - . - - _ . - - . - - - - - . - - . - . - . - ~ _ . - ..

i 1

DISMANTLEMENT AND DEMOLITION PROCESS Upon issuance by the USNRC of the TSCR to remove the C&A, RWDF, FDSB, and RWST pad from Technical Specification controls, each of the structures will be readied for distaantlement. It is SNEC's intent to restore the land to its original _ contour such that it will have no impact upon the U.S. Army Corps of Engineers' flowage easement. There wil,' be no regulated demolition landfill created. '

Masonry material from the demolition of structures to 3 feet below grade will be used as backfill in the RWDF basement and the yard

. pipe tunnel. The backfilled RWDF basement and yard pipe tunnel will be covered with a soll cap. Construction robar and other non-masonry materials will be removed to the extent possible from the concrete prior to its use as backfill material. Other non-masonry materials from the buildings such as glass and roofing, will be removed to.the extent possible. Excess concrete rubble that can not be used as backfill and other non-masonry materials will be disposed of offsite in an approved landfill or recycled.

The _ filled' drum storage bunker is an earthen unit with wooden cribbing. The interior wall consisting of the wood-cribbing-will be' surveyed-in accordance with procedures for release of-equipment.

If the wood cribbing meets USNRC guidelines for release it will be disposed of offsite in an approved landfill.

All applicable dismantlement and demolition permits will be secured prior to the start'of work. Demolition work will be conducted in a manner to. minimize any environmental impact.

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.h- a 'msa w

,.- 6 .- A .msAx,, .g.-.._. 4wam -A 4i A e w,,tg -

d 4

{THIS PAGE INTENTIONALLY LEFT BLANK) 1

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Appropriate radiological and environmental controls will be in place throughout the dismantlement and demolition process. Several areas were identified during the final release survey that were inaccessible to survey instruments. These areas will be surveyed and dispositioned during dismantlement and denolition. Demolition hold points have been identified to allow these additional surveys to occur. The USNRC will be notifiad of the status of each hold point after each has been surveyed. If the hold point meets USNRC release guidelines, the USNRC will be given the option to reviow the results before fi 11 dieposition. If the hold point is

, considered to be radwaste, it will be disposed of in accordance jf) with procedures for radwaste. These hold points include:

i.

o walls behind the electrical breaker boxes and emergency lighting fixtures (C&A and RWJF) o structural I-beams in C&A o drain pipes off of the C&A roof 4 o floors underneath groundwater collection containers (RWDF) o ceiling hatch in the RWDF Evap. Room o area underneath wooden f rame " bridge" in the C& A pipe tunnel o area underneath groundwater collection pipes in the RWDF pipe tunnel o two pipes in RWDF Pump and Compressor Room ceiling o two pipes in RWDF Drum Shipping Room o areas underneath any wooden supports s o several penetrations in Yard Pipe Tunnel ceiling Radiological Controls technicians will provide job coverage throughout the dismantlement and demolition process. They will bo instructed to Furvey the hold points identified above as well as any add tional areas not previously surveyed that may becomo accessible. If any areas / materials exceed the USNRC release

- 704 -

guidelines, they will either be decontaminated to satisfy release criteria or dispositioned offsite as radwaste.

Special surveys identified several penetrations and areas that were not decontaminated to below USNRC release guidelines. They also have been designated as demolition hold points. They will be removed during demolition to ensure residual contamination is as low as_ reasonably achievable. These hold points include:

o structural I-beams in C&A Auxiliary Equipment Room o 2 drain pipes in the floor of the C&A Toilet and Shower Room o pipe in chlorinator / sewage treatment building o 9 pipes in the RWDF building and yard pipe tunnel o 22 electrical conduits located underneath the concrete floors in the C&A Switchgear and Variable Frequency Rooms o drain pipe in floor of C&A Auxiliary Equipment Room Excess structural materials that can not be used as backfill, will be disposed of offsite. This material will receive additional monitoring prior-to release from the site. _

-To provide assurance that these precautions and requirements are met, a staff of Radiological Controls technicians will be matntained at the site during demplition. This staff will be supervised by a TMI qualified Group Radiological Controls Supervisor (GRCS) or the Saxton Radiation Safety Officer (RSO).

The soil underneath the buildings has been sampled and analyzed and found to be consistent with the unvironmental pathways analysis and the NRC guidelines provided in the Oak Ridge Associated University

_ Confirmatory Survey Report. The soil immediately surrounding the buildings was also-sampled and analysed. Measures will be-taken

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__ . ._ _ _ .. . . . . ~ . . _ . . . - _ _ . _ ___.._ ._.._.- _ _ _ _ _ _. . . , _ _ . _

4 4

l i

during demolition to prevent soil that does not satisfy the l environmental pathways _ analysis _ guidelines from intermixing with )

the concrete rubble. Clean fill from offsite will be used to fill  ;

void areas among the concrete rubble in the RWDF basement and yard pipo tunnel.

Appropriato er.vironmental monitoring will continue to be performed during the demolition process.

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h 4

ATTACHMENT 2 PLAN OF ACTION TO DISPOSITION THE FILLED DRUM STORAGE BUNKER a

I ru ii

s-e PLAN OF ACTION TO DISPOSITION THE FILLED DRUM STORAGE BUNKER The FDSB is a timber and earthen structure that was used as temporary storage for low level radwaste during plant operations.

The structure consists of four walls and a floor. The internal walls are composed of timbers arranged in matrices intertwined with soil. The top 6 to 12 inches of surficial materials were removed from the outside walls leaving 2 to 4 feet of clay soil.

The drums of soil and pile of soil that were being stored inside the bunker were removed to gain access to the btrnker and the macadam floor. The soil was relocated to the north side of the SNEC area fence and was stabilized to prevent erosion. and sedimentation problems. The macadam floor of the bunker was surveyed using a gamrna scintillation detector with a ratemeter.

Measurements greater than 2 times background levels were excavated and will be dispositioned appropriately.

The outside walls were gridded (3 meters x 3 meters) and soil samples were_ collected and analyzed from each grid. Soll core samples (2 to 4 f eet) were taken f rom the inside and outside walls.

Samples were also taken of the soil that became exposed after excavation of contaminated sections of the macadam floor. Figure 1 shows the sample locations and Tables 1, 2, and 3 contain the radiological results of the grids, soll cores, and soil floor, respectively.

i

Following opproval of Tech. Spec. Change Request No. 53, the FDSB will be dismantled by a demolition contractor. The timbers will be dismantled and separated from the soil. They will be surveyed in accordance with procedures for survey and releese of equipment and materials for unrestricted use. The release criteria will be consistent with the NRC IE Inf.ormation Notices 81-07 and 85-92.

Any timbers found to be-greacer than the release criteria will either be decontaminated and resurveyed or disposed of an low level radwaste. The timbers will be staged onsite and the USNRC will be notified of their status. The USNRC has the option to review the results and/or conduct verification surveys before final disposition. After final approved release, the timbers may be recycled or disposed of offsite in an approved landfill.

The soil component of the bunker will remain onsite and stabilized to prevent erosion and sedimentation problems. The macadam floor will also remain onsite. Final release of the soil and macadam floor will be addressed at the time of final site closure.

-i-FIGURE'I I

eI.I.ED DilUM STORAGE BUNKER (FDStQ

( La you t. of Grids 6ad Sample 1,ocat_ ions)

NOR't ;I (C2) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (Cl)

(11) (G) (D) (C) (B) (A) 19 (E) -

20 21 22 23 24 25 28 29 WEST EAST (C6) 26 27 (CS) 32 33 (C7)

(JI) 30 31 (I) (F) (C3) 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 (C4)

SOUTH I

4 TABLE 1 -

SOII. RESULTS FROM FDSB OUTSIDE WAI.I. GHIDS Cs-137 pCi/gm Grid No. Cs-137 pC1/qm Grid No. Cs-137 pCi/qm Grid No. Cs-137 pCi/qm 1 1.7 1. 0 . 2 20 0.73 1 0.07 39 2.5 1 0.2 2 71.0 1 7 21 0.92 1 0.09 40 2.6 1 0.3 3 5.3.1 0.5 22 8.0 1 0.8 41 5.6 1 0.6 4 1.2 1 0.1 23 2.4 1 0.2 . 42 13.0 1 1 5 0.55 1 0.07 24 3.0 1 0.3 43 2.3 1 0.2 6 0.98 1 0.1 25 0.50 1 0.06 44 0.79 1 0.08 7 0.49 1 0.06 26 1.3 1 0.1 45 0.34 1 0.06 8 5.5 1 0.5 27 17.0 1 2 46 0.31 1 0.05 9 5.6 1 0.6 28 1.4 1 0.1 47 3.1 1 0.3 10 0.09 1 0.029 29 1.1 1 0.1 48 2.6 1 0.3 11 1.4 1 0.1 30 7.5 1 0.8 49 1.5 1 0.2 12 0.91 1 0.09 31 5.8 1 0.6 50 0.82 1 0.08 13 0,56 1 0.06 32 0.78 1 0.08 51 1.2 1 0.1 14 0.26 1 0.04 33 3.1 1 0.3 52 2.7 1 0.3 15 0.29 1 0.05 34 2.4 1 0.2 53 1.5 1 0.1 16 0.44 1 0.05 35 1.8 i 0.2 54 2.1 1 0.2 17 0.97 1 0.01 36 7.0 1 0.7 55 2.1 1 0.2 18 0.76 1 0.08 '

37 18.0 1 2 56 5.1 1 0.5 19 6.8 1 0.7 38 9.9 1 1 57 2.7 1 0.3 5

-o TABLE 1 (Cont'd)

SOIL RESULTS TROM FDSB OUTSIDE WALL GRIDS Co-60 pC1/gm Grid No. Co-60 rC1/qn

-2 0. 51 + 0. 08 35 0.18 + 0. 04 38 1.2 + 0.05

-42 0.1610.05 43 0.1210.05 l

l t

(

l

a

• e TABLE 2 RESULTS OF SOIL CORES FROM INSIDE AND OUTSIDE WALLS OF THE FDSB CORE I.D. Cs-137 pCi/qm C1 (inside wall) 0.26 + 0.05 C2 (outside wall) <0.04 C3 (inside wall) 2.6 0.3 C4 (outside wall) <0.07 CS (inside wall) 2.9 0.3 C6 (outside wall) 0.33 0.06 C7 (out side wall) <0.05

7 e

TABLE 3 RESULTS OF SOIL SAMPLES FROM EXCAVATED HOLES IN THE FDSB FLOOR SOIL NO. Cs-137 pCi/om A 0.92 1 0.09 B

0.22 1 0.06 C 4.8 0.5 D 0.49 1 0.05 E

0.043 1 0.029 F 1.8 1 0.2 G 2.8 + 0.3 H 7.9 + 0.8 I

2.1 1 0.2 J 5.0 1 0.5