r

SMUD

SACRAMENTO MUNICIPAL UTILITY DISTRICT

The Power To Do More.m

P.O. Box 15830, Sacramento, CA 95852-1830; 1-888-742-SMUD (7683)

MPC&D 07-028

April 2, 2007

U.S. Nuclear Regulatory Commission

Attn.: Document Control Desk

Washington, DC 20555

Docket No. 50-312

Rancho Seco Nuclear Generating Station

License No. DPR-54

RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION

Attention: John Hickman

In your letter dated February 27, 2007, you requested additional information required to

complete the NRC's review and approval of the Rancho Seco License Termination Plan (LTP)

and associated environmental assessment. Attached is our response to your request.

Members of your staff with questions requiring additional information or clarification may

contact Bob Jones at (916) 732-4843.

aSinceI.

Steve Re er

Manag, lant Closure & Decommissioning

Attachment

Cc w/ attachment: B.S. Mallett, NRC, Region IV

P raý60 (

RANCHO SECO NUCLEAR PLANT - 14440 Twin Cities Road, Herald, CA 95638-9799; (209) 333-2935
Response to RAIs Dated February 27, 2007

ENVIRONMENTAL ISSUES

1. Section 8.6.3.13, Aesthetics Issues, states that the District intends on leaving the

major concrete plant structures in place after the completion of decommissioning

and license termination. It is understood that temporary structures will be

dismantled and removed.

a. Please describe any plans for restoration, re-vegetation, and other permanent

environmental measures (e.g., erosion controls) at the site (e.g., areas of the

site where temporary structures will be dismantled and removed).

Response

In most cases, concrete floor slabs are abandoned in place as building structures are

dismantled. In rare instances where erosion issues may be created by building

dismantlement, asphalt paving, gravel, or re-seeding with native grasses will be used to

prevent erosion.

An example of concrete floor slabs abandoned in place from dismantled structure is

shown in the following before and after photographs.

April 2, 2007 Page 1 of 61
Response to RAIs Dated February 27, 2007

Before

After

Apd1l2, 2007 Page 2 of 31
Response to RAIs Dated February 27, 2007

b. Please describe the approximate acreage of the site occupied by

infrastructure (e.g., buildings, roads, parking lots) prior to decommissioning

and what that acreage would be after the site is released from NRC licensing.

Response

The acreage of the site occupied by infrastructure (e.g., buildings, roads, parking lots)

will not change after the site is released from NRC licensing. The majority of the

infrastructure is contained within the existing 87-acre Industrial Area. The only.

exceptions are the Hazardous Material Warehouse, the Receiving Warehouse and

portions of the paved site access road. The Hazardous Material Warehouse will be

demolished down to its concrete pad prior to completion of the first phase of license

termination. The fence enclosing the Industrial Area will not be removed during

decommissioning. Upon completion of the first phase of license termination the

Industrial Area will be maintained as an industrial site with access controlled by the

SMUD Asset Protection'Department (industrial security). The Interim Onsite Storage

Building (IOSB), which will remain under the 10 CFR Part 50 license, will be contained

within this industrial site. The Backup Control Center (BCC) in the former

Administration Building, the Training and Records Building with occupied offices and the

active switchyard will also be contained within this industrial site. The Independent

Spent Fuel Storage Instillation (ISFSI), which is licensed under 10 CFR Part 72, is

accessible only from the industrial site. No existing roads or parking lots will be

removed during decommissioning. Upon completion of the second phase of license

termination, access to the industrial site will continue to be controlled by the SMUD

Asset Protection Department.

Before and after decommissioning aerial photographs of the Industrial Area are

provided below.

April 2, 2007 Page 3 of 31
Response to RAIs Dated February 27, 2007

April 2, 2007 Page 4 of 61
Response to RAts Dated February 27, 2007

Apri 2, 2007 Page 5 of 61
Response to RAIs Dated February 27, 2007

c. Please identify potential environmental effects (e.g., on migratory birds and

raptors) from the structures (e.g., hyperbolic cooling towers) that will remain in

place after unrestricted release of the site or portions of the site. Include any

related requirements that will need to be complied with after release of the

site or portions of the site from NRC licensing (e.g., avian protection related

acts).

Response

The environmental effects from the structures that will remain in place after unrestricted

release of the site or portions of the site will be no different than the effects that existed

during plant operation and the period of time following final plant shutdown and license

termination. The remaining structures are large stationary objects that are readily

observed by migratory birds and raptors and thus easily avoided. Removal of these

structures would have a negative impact on the nesting of migratory swallows because

large numbers of them build their mud nests on these structures.

The State of California is concerned about avian safety and has conducted numerous

studies related bird fatalities caused by collision with overhead power lines and wind

turbines used in the generation of electricity from wind power. However, they have not

conducted studies of bird fatalities caused by collision with stationary structures. Also,

the California Energy Commission has instituted an investigation into the development

of statewide guidelines for reducing wildlife impacts from wind energy development.

d. Please provide a listing to clarify which specific structures will likely remain

standing at the site after release from NRC licensing.

Response

Most of the major concrete structures will remain in place. All paved areas will remain

paved. Below are "Structures Figure 1", showing the buildings located near the power

block, and "Structures Figure 2", showing the remaining structures in the vicinity of the

Industrial Area. A red "X" indicates that the structure has or is scheduled to be

removed, leaving only the concrete pad of the structure for Final Status Survey. Note

that the cooling towers and cooling tower basins will remain following License

Termination. All planned structure demolition will occur before Final Status Surveys are

complete for the first phase of the License Termination Plan (LTP).

April 2, 2007 Page 6 of 61
Response to RAIs Dated February 27, 2007

The following buildings shown in "Structures Figure 1" will remain after License

Termination:

1. TDI Diesel Buildings

2. Back-up Control Center (formerly Administrative Building)

3. Training & Records Building

4. Nuclear Service Electrical Building

5. Auxiliary Building

6. Reactor Containment Building

7. Spent Fuel Building

8. Turbine Building

9. Switchyard Control Building

10. Machine Shop (includes area formerly known as the "A" Warehouse)

11. "B" Warehouse

12. Personnel Access Portal (PAP) Building

April 2, 2007 Page 7 of 61
Response to RAls Dated February 27, 2007

The following buildings shown in "Structures Figure 2" will remain after License

Termination:

13. ISFSI

14. Interim Onsite Storage Building

15. Receiving Warehouse

16. Unfinished Technical Support Building

2. Please summarize any changes that are planned for the site storm drain system

and outfall discharge pipes, including the portions of the system that provide

drainage from the switchyard and the Independent Spent Fuel Storage

Installation (ISFSI).

Response

No changes are planned that will affect the storm drain outfall discharge pipes. Minor

rerouting within the storm drain system will be required within the Industrial Area

because of demolition activities but this rerouting will not affect the outfall discharge

pipes. The switchyard is energized and being used by the Cosumnes Power Plant as

discussed in Section 6.4.2.1 of the LTP. No changes have or are planned to be made

to switchyard storm drain system. No changes will be made to the ISFSI storm drain

system as a result of the 10 CFR Part 50 license termination.

April2, 2007 Page 8 of 61
Response to RAIs Dated February 27, 2007

3. Section 3.3.6.1, Deferred Activities, Storage of Class B and C Waste, states that

it is the decision of the District management that acceptable waste disposal

options for Class B and C waste do not exist at this time. Further, the waste will

be stored in the IOSB until such time as an acceptable waste disposal site is

available, when the waste will be shipped and the building will be

decontaminated as required. Additionally, Section 8.3, Site Description After

Unrestricted Release, states that the District intends to release the site for

unrestricted use in two phases, with the majority of the site released in the first

phase. The second phase is identified as release of the IOSB, which is indicated

as remaining on the 10 CFR Part 50 license until the license is terminated with

the unrestricted release of the IOSB.

a. Please confirm that the current maintenance and monitoring procedures used

for the site include the IOSB, including physical and radiation monitoring of

the facility and waste containers. Please specifically confirm that the IOSB is

addressed in the current environmental monitoring, emergency, and security

plans.

Response

Rancho Seco implements its maintenance program on an ongoing basis to ensure that

plant equipment maintains its required level of performance. The maintenance program

applies to both the 10 CFR Part 50 decommissioning site and the 10 CFR Part 72

licensed Independent Spent Fuel Storage Installation (ISFSI). The maintenance

program will continue to be implemented as long as the IOSB is operational and spent

nuclear fuel is stored at the ISFSI.

The Rancho Seco Radiation Protection Plan discusses the philosophies, policies, and

objectives of the radiological controls program. Implemented by site technical and

administrative procedures, the radiological controls program is designed to control

radiation hazards, avoid accidental radiation exposures, prevent unauthorized access to

radioactive material, and to maintain radiation dose to workers and the public below

regulatory limits and As Low as Reasonably Achievable (ALARA). The radiological

controls program is integrated into all radiological operations at Rancho Seco, including

the IOSB.

The radiological controls program applies to both the 10 CFR Part 50 decommissioning

site and 10 CFR Part 72 licensed ISFSI. The radiological controls program will continue

to be implemented as long as there is licensed radioactive material at the Rancho Seco

site.

Radioactive waste procedure RP.309.IV.01, "OS Building Operations" specifies the

requirements for operational activities in the IOSB. This procedure addresses

warehouse operations to ensure that stacking requirements are maintained and that

dose rate limits are not exceeded. The procedure also addresses ventilation system

operations, container handling and inspection requirements, and crane operations.

These procedural requirements will remain in effect as long as the IOSB is operational.

April 2, 2007 Page 9 of 61
Response to RAIs Dated February 27, 2007

The Rancho Seco Radiological Environmental Monitoring Program (REMP) is designed

to meet applicable regulations and to provide an accurate assessment of the

radiological environment in and around the environs of the Rancho Seco site. The

REMP applies to both the 10 CFR Part 50 decommissioning site and 10 CFR Part 72

licensed ISFSI. The REMP will continue to be implemented as long as the spent

nuclear fuel remains stored at the Rancho Seco ISFSI.

Similarly, the Rancho Seco Emergency Plan applies to both the 10 CFR Part 50

decommissioning site and the 10 CFR Part 72 ISFSI. As decommissioning progresses

and the radiological source term is reduced, the emergency planning requirements may

also be reduced without reducing the effectiveness of the plan. The emergency plan

will remain in effect long as the spent nuclear fuel remains stored at the Rancho Seco

ISFSI.

The Rancho Seco 10 CFR Part 50 licensed facility is exempt from 10 CFR Part 73

security requirements. Accordingly, the IOSB is not covered under an NRC-approved

security plan. SMUD provides industrial security for the 10 CFR Part 50 site. SMUD

management determines the level of security provided for the Rancho Seco Industrial

Area.

b. Please identify the approximate area size and location of the fence line and

gate for the portion of the site that will remain on the license with the IOSB

and the relationship to the spent fuel storage area, including both the

distances between the spent fuel and the IOSB fence lines. Also, indicate the

location and expected readings for maximum radiation levels between the

IOSB and spent fuel storage area. If the land between the spent fuel storage

area and IOSB is not going to remain on the license, indicate the anticipated

maximum radiation doses in this region where unrestricted release is

occurring between the two fence lines and provide the analysis to assure that

10 CFR Part 20 public dose limits will not be exceeded (using dose

contributions from the ISFSI, released area, and IOSB). Additionally, please

identify these locations on a map or diagram.

Response

The figure "Proposed IOSB Fence" below shows the building footprint and relative

locations of the bermed area, the boundary fence, the gates east of the IOSB and the

approximate distances of the fence lines to the nearest portions of the building. The

total footprint that the 10 CFR Part 50 licensed site will occupy after Phase 1 of License

Termination is encompassed by the rectangular area within the fence, and is

approximately 300-feet east-to-west by 160-feet north-to-south. The total area is

approximately 1.1 acres.

April 2, 2007 Page 10 of 61
Response to RAIs Dated February 27, 2007

Earth Berm

1/

Rip rap for erosion control,

5012, 1ý

ILISB

- 0.5 f t-

--90 f-tI

paved

f ILL -Pence

I

70 iP-t

North -,Fý

The figure "Fence Lines" below indicates the approximate location of the fence line

proposed for the IOSB (shown in blue) and the approximate location of the 100-meter

fence that is in place around the ISFSI (in red). The green lines approximate the current

outer portion of the industrial area fence that will remain in place. The purple line

labeled "A" is the shortest distance between the IOSB and ISFSI fences, which is

approximately 130 feet. Access to the area within the red lines is controlled by the

10 CFR Part 72 license. Access to the area within the blue lines will be controlled by

the 10 CFR Part 50 License between Phase I and Phase II of License Termination.

April 2, 2007 Page 11 of 61
Response to RAIs Dated February 27, 2007

Radiation levels outside of the fence lines of both facilities are statistically not

distinguishable from background. The Radiological Environmental Monitoring Program

measures the long-term dose rates at locations around site, including around the

perimeter of the ISFSI. Personnel dosimeters are placed on the 100-meter fence at the

locations indicated with white numerals in the figure "Fence Lines" above. The tables

below indicate the results of quarter-long monitoring with dose given in mRem/quarter.

Locations 1 through 6 refer to the locations in the figure. Locations C-1 through C-6 are "control" locations, away from the site, used to determine the local background radiation

levels in the area.

Data for the years 1997, 1998, 2001, and 2006 are included. Fuel storage into the

ISFSI commenced in 2001, and was completed in 2002. 1997 and 1998 provide

indication of the levels in the area prior to placing fuel into the ISFSI. The last Class B

and C waste to be stored in the IOSB was generated during the segmentation of the

Reactor Vessel Internals. The project was complete and all the waste intended for

storage between Phase I and Phase II was in storage in the IOSB by the end of the 2 nd

quarter of 2006. Even though there is an apparent increase in the total dose received

by the dosimeters at the ISFSl boundary compared to the dose of the control locations,

Apdil2, 2007 Page 12 of 61
Response to RAIs Dated February 27, 2007

the difference remains statistically small. Mathematically, comparing the highest

average indicator locations with the lowest average control locations in any given year

results in a difference of 2.5 mrem/quarter or 10 mrem/year due to the ISFSI.

In 2006, after all waste intended for storage was actually in storage at the IOSB,

surveys were performed outside the perimeter fence surrounding the IOSB using 2" X 2"

Nal detectors. These surveys were conducted to determine if the waste in storage at

the IOSB would interfere with the planned MARSSIM surveys of the surrounding areas

for License Termination. The surveys indicated that the gamma field along the fence

was the same as the gamma field measured in Class 3 areas that are shown through

sampling and laboratory analysis to have no detectable contamination from plant origin.

Since the surveys, which indicated levels of 6,000 to 8,000 cpm, are no different than

background in a Class 3 area, the dose consequences are not greater than that from a

Class 3 soil survey unit. To date, no Class 3 soil survey units have indicated

measurable contamination of plant origin above background. Therefore, it can be

assumed that the dose resulting from occupancy in these areas would be less then 10%

of the 25 mrem/year allowed dose, or less than 2.5 mrem/year.

Since the land areas around the ISFSI are either non-impacted (North, West, South

areas surrounding.the ISFSI), or Class 3 areas (East of ISFSI), worst case dose impact

from residual radioactivity would be less than 10% of the annual limit, or 2.5 mrem/year.

Combined with a maximum 10 mrem/year from the ISFSI and 2.5 mrem/year from the

IOSB, the resulting dose to an industrial worker occupying the land areas between

these two facilities would be a maximum of 15 mrem/year, which is below the 25

mrem/year limit allowed for license termination.

Year 1997

Quarter Q1 Q2 Q3 Q4 Avg

Location _

1 13.1 14.1 16.4 15.4 14.8

2 16.0 15 14.8 16.4 15.6

3 13.8 14.7 16.2 15.6 15.1

4 14.2 16.3 15.9 16.1 15.6

5 17.5 15.4 16.1 19 17.0

6 13.9 14.4 14.7 15.7 14.7

Qtr Avg 14.8 15.0 15.7 16.4 15.4

C-1 12.7 14.4 15.3 16.6 14.8

C-2 14.2 17.5 Note 1 21.1 17.6

C-3 11.7 12.6 15.5 15.8 13.9

C-4 12.7 15.3 14.1 14.8 14.2

C-5 11.0 13.9 14.2 13.9 13.3

C-6 13.7 14.4 14.7 16.7 14.9

Qtr Avg 12.7 14.7 14.8 16.5 14.8

April 2, 2007 Page 13 of 61
Response to RAIs Dated February 27, 2007

Year 1998

Quarter Q1 Q2 Q3 Q4 Avg

Location

1 13.6 14.1 14.2 15.6 14.4

2 13.6 14.1 16.8 15.4 15.0

3 14.4 14.0 15.0 15.4 14.7

4 20.7 14.6 14.3 15.2 16.2

5 15.9 14.6 15.2 15.6 15.3

6 14.1 17.4 14.2 15.7 15.4

Qtr Avg 15.4 14.8 15.0 15.5 15.2

C-1 15.4 17.2 13.9 14.3 15.2

C-2 17.2 16.3 19.3 16.5 17.3

C-3 12.4 13.8 12.8 13.3 13.1

C-4 15.7 14.3 14.0 15.4 14.9

C-5 13.7 13.5 13.1 13.6 13.5

C-6 11.8 13.8 14.2 14.6 13.6

Qtr Avg 14.4 14.8 14.6 14.6 14.6

Year 2001

Quarter Q1 Q2 Q3 Q4 Avg

Location

1 17.0 15.0 15.0 14.0 15.3

2 17.0 18.0 19.0 18.0 18.0

3 18.0 17.0 17.0 18.0 17.5

4 17.0 17.0 17.0 18.0 17.3

5 18.0 17.0 18.0 17.0 17.5

6 16.0 16.0 14.0 14.0 15.0

Qtr Avg 17.2 16.7 16.7 16.5 16.8

C-1 16.0 15.0 17.0 17.0 16.3

C-2 22.0 19.0 20.0 Note 1 20.3

C-3 14.0 Note 1 14.0 15.0 14.3

C-4 17.0 15.0 17.0 22.0 17.8

C-5 15.0 12.0 13.0 12.0 13.0

C-6 16.0 18.0 15.0 11.0 15.0

Qtr Avg 16.7 15.8 16.0 15.4 16.1

April 2, 2007 Page 14 of 61
Response to RAIs Dated February 27, 2007

Year 2006

Quarter Q1 Q2 Q3 Q4 Avg

Location

1 25.0 25-0 19.0 21.0 22.5

2 18.0 22.0 21.0 20.0 20.3

3 19.0 19.0 18.0 19.0 18.8

4 24.0 24.0 20.0 24.0 23.0

5 19.0 21.0 18.0 17.0 18.8

6 23.0 23.0 20.0 21.0 21.8

Qtr Avg 21.3 22.3 19.3 20.3 20.8

C-1 Note 2 Note 2 Note 2 Note 2 Note 2

C-2 19.0 20.0 Note 1 21.0 20.0

C-3 17.0 16.0 14.0 15.0 15.5

C-4 18.0 21.0 22.0 19.0 20.0

C-5 Note 2 Note 2 Note 2 Note 2 Note 2

C-6 17.0 20.0 16.0 18.0 17.8

Qtr Avg 17.8 19.3 17.3 18.3 18.3

Note 1: No data available, the dosimeters were missing when collected

for end of the quarter monitoring.

Note 2: Monitoring at these locations ceased after 2004 as the REMP

program was reduced.

c. Please identify access roads and paths that will continue to exist after the first

phase of site release and will be located nearest to the new IOSB fence line,

including location and distance from the IOSB. Clarify whether access to

these roads and paths are controlled in some way or available for public

access. Please include travel volume estimates for these roads and paths.

Additionally, please identify the locations on a map or diagram.

Response

The figures "Structures Figure 2" and "Fence Lines" included earlier provide aerial views

of the areas around the IOSB. The nearest "road" would be the area just east of the

IOSB, where the controlled access fence will be placed approximately 70 feet from the

eastern wall of the IOSB. The road west of the IOSB is also at its closest point

approximately 70 feet away from the North-West corner of the IOSB,*but a berm

separates the building from the surrounding areas on all sides but the East.

All of these roads are within the Industrial Area. Access to the Industrial Area postLicense Termination has been discussed thoroughly in Section 6.4.2 of the LTP. As an

update to that information, the Backup Control Center (Building "2" in.figure "Structures

Figure 1" included above) is now operational and has been used to operate the District's

electrical distribution system. The District will maintain a level of access control to the

current Industrial Area in order to maintain the security required by the Federal Energy

April 2, 2007 Page 15 of 61
Response to RAIs Dated February 27, 2007

Regulatory Commission (FERC) and other regulatory agencies governing reliability of

electrical distribution systems. The public will not have free access to these areas.

d. Please indicate if there are plans to store non-radioactive waste in the IOSB.

Also, clarify whether or not there are any plans to store waste from other

facilities at the IOSB and whether or not this waste is radioactive waste.

Response

There are no plans to store any waste other than Class B and Class C radioactive

wastes generated at the Rancho Seco facility. Publicly elected representatives from

other portions of the state of California have proposed storage of radioactive materials

generated at other locations (i.e., radiologically contaminated medical waste) due to the

implementation of the Low Level Waste Policy Act, and the lack of an in-compact

disposal site for California waste generators. However, the District Board of Directors,

and District management and staff strongly oppose storage of any materials at Rancho

Seco other than the Class B and Class C radioactive wastes generated at the facility.

4. Section 8.5.1.3.1, Land Use, states that the Rancho Seco Updated Safety

Analysis Report (USAR) Figure 2.2-6 provides a detailed description of all

agricultural and residential activities within a 5-mile radius of the site, and USAR

Figures 2.2-7, 2.2-8, and 2.2-9 identify agricultural activities within a 50-mile

radius.

a. The Defueled Safety Analysis Report (DSAR), Amendment 2, Section 1.1,

Introduction, states that the DSAR replaced the USAR as the primary

licensing basis document applicable to Rancho Seco in the Permanently

Defueled Mode. Further, Figure 2.2-4 of this document appears to be the

only figure in the DSAR that identifies agricultural uses. Given these

differences in descriptions between the Supplemental Environmental Report

reference to the USAR and the DSAR, please provide new copies of the

appropriate figures that identify current agricultural and residential activities to

better assure that our review is addressing the applicable information.

Response

Attached below are Figures 2.2-7, 2.2-8, and 2.2-9 of the Rancho Seco USAR. These

figures represent the agricultural activities within a 50-mile radius of the plant.

The USAR represented the licensing basis for Rancho Seco when the plant was still

operating. USAR, Amendment 8 was in effect when SMUD submitted the original

Decommissioning Plan and the associated Supplement to Rancho Seco Environmental

Report - Post Operating License Stage. After Rancho Seco shut down permanently,

the DSAR replaced the USAR as the primary licensing basis document to reflect the

operation of Rancho Seco in the permanently de-fueled mode.

April 2, 2007 Page 16 of 61
Response to RAIs Dated February 27, 2007

After all of the fuel was placed in dry storage, the DSAR was further reduced to reflect

that the Emergency Planning Zone (EPZ) was limited to the Industrial Area boundary.

With the reduced size of the EPZ, a detailed description of the surrounding area (e.g.,

population and land use) were no longer relevant and were removed from the DSAR.

Historical information remains available in USAR Amendment 8.

Agricultural activities within the 50-mile radius remain largely unchanged. Two notable

changes are wine grapes planted to the north and west of the plant and construction of

the Cosumnes Power Plant approximately 1⁄2 mile south of the Rancho Seco facility and

within the 2,480 acre SMUD owned site.

b. Please identify references used for any information provided. Further, please

include a brief written explanation of the figures provided.

Response

Figures 2.2-7, 2.2-8, and 2.2-9 are contained in USAR, Amendment 8.

Figure 2.2-7 shows fruit, nut, and field crops, Figure 2.2-8 shows pastureland and

rangeland, and Figure 2.2-9 shows land used for dairy cattle.

April 2, 2007 Page 17 of 61
Response to RAIs Dated February 27, 2007

34.1.. . .

Scole in miLeS '.

o110 0 10 20 5-0 40 5,0

40 5,0

Fruits & huts

Sq mr of Fteld Clo ts

SOURCEr Ainuol Agriculturol Crop Reports

Colifornia State Departmenl Of

Ag rnict u rot

FIGURE 22-7

CURRENT LAND USE , FRUITS

AND NUTS AND FIELUD CROPS

SMUU

•ACRAMENTO MUNI.PAL UTIUTY DISTRCCT

April 2, 2007 Page 18 of 61
Response to RAIs Dated February 27, 2007

3.9

J 5o0

/

Co.

2,1

328,11 Staanis/4os

10 0 10 20 30 40 50

FIGURE 2.2.8

CURRENT LAND USE -

5Q m 01 Posture PASTURE LAND AND RANGE LAND Land

5~ m o-Roage Loifd

SOURCE- Anrnual AgriculoinJal Crop Reports

Ccjliformio 'State Deporiment of SMUD

AgrictturO1l SACRAMENTO MUNICPAL UT7UTY DISTRICT

April 2, 2007 Page 19 of 61
Response to RAIs Dated February 27, 2007

'S,Safter co.

*170

k..

•o+ 1.700

N'=

(AN

yltv

I-. •m=q = •e'. 

Tuo v/aine

CO,

AlImeda Co.

Stonis/os$ CO.

NOTE No d.ary coUIle

withh iji a 5 Ie

5 cae in miles '5

100 0 20 30 40 50

it'd ius

FIGURE 2.2M9

CURRENT LAND USE - Dairy ile ',i yrs. DAIRY CATTLE S over

S0UACE- Cal.ifornig Srale Depa.tnmena

Md Aq~:cuoIciaf SMUD)

SACRAMENTO MUNICIPAL UTILITY DISTR!CT Divusoini of C:ov LRt Porffubq

April 2, 2007 Page 20 of 61
Response to RAIs Dated February 27, 2007

5. Section 8.5.4.1, Hydrology, states that within recent times no flooding or

inundation from storms or runoff has occurred within the site boundaries.

Further, it is highly unlikely that the site could be flooded, even with abnormal

rainfall intensities.

a. Please identify what period of years the wording "in recent times" is intended

to include.

Response

The term "within recent historical times" has been used in Rancho Seco licensing basis

documents without definition beginning with the Preliminary Safety Analysis Report

(PSAR) submittal and currently exists in the DSAR. As indicated in the response to RAI

5.c below, the Rancho Seco site is outside the 100-year floor plain. Therefore, term "within recent historical times" can be defined as a period of time greater than 100

years.

b. Please provide the specific reference(s) for the source(s) of both the "recent

times" determination and conclusion that it is highly unlikely that the site could

be flooded.

Response

Please refer to the response to RAI 5.c below.

c. Please identify the location of the nearest flooding outside of the current site

boundaries for the same period of years or at least the last 100 years,

whichever is the longest period of time.

Response

The answer to this RAI was provided in response to RAI No. 40 contained in the first set

of RAIs. Creeks, streams, rivers and other surface water drainage features along with

flood elevations are shown on Figures 2-2 and 2-3 in the Hydrogeological

Characterization Report. 100-year flood plain maps for the immediate areas

surrounding the Rancho Seco site are shown on Figure 2-3. General 100-year flood

area information for Sacramento County may be viewed at

http://www.msa.saccounty.net/waterresources/floodready/FloodMap.pdf. Figure 2-3 from the

Hydrogeological Characterization Report is provided on the next page followed by a

portion of the map located at the referenced url, which shows the 100-year flood plain

near the Rancho Seco site location without contour lines. As shown on the two maps,

the nearest 100-year flood plain outside of the current site boundaries results from

Hadseville Creek north of Twin Cities Road (Hwy 104) across from the main entrance

to the site.

April 2, 2007 Page 21 of 61
Response to RAIs Dated February 27, 2007

Apd12,2007 Page 22 of 61
Response to RAls Dated February 27, 2007

I/

RSNGS Site

1L

I N

100 Year Flood Area

Based on Federal Insurance Rate Map, Index dated

July 6, 1998. Total Floodplain area 149,458 ac .E

HA

* AE

0 A99

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.11]

The above ZONES Indicate areas within the Special

Flood Hazard Area (Flood Insurance may be required!)

[L1 X (NotIn Special Flood Hazard Aea)

April 2, 2007 Page 23 of 61
Response to RAIs Dated February 27, 2007

6. Throughout the plan and, especially, in Chapter 2, Site Characterization, the

terms Industrial Area, Area 8, Impacted Area, and Un-Impacted area are used

(example: Sections 2.1.7.3, 2.1.10, and Section 2 figures).

a. Please clarify the size of each area (e.g., acres), other than the Industrial

Area (already indicated in the LTP).

Response

LTP Figure 2-1 shows the Industrial Area of the Rancho Seco site. As stated in

LTP Section 1.3.2 "Site Description," the Industrial Area is 87 acres. LTP Section

2.1.8.4 "Area 8" defines Area 8 as being the Industrial Area. Therefore, the size

of Area 8 is also 87 acres.

LTP Figure 2-2 shows the Impacted Area. The size of the Impacted Area is

approximately 165 acres. Accordingly, the size of the Un-Impacted Area is

approximately 2,315 acres.

b. Please clarify the location of barriers and access points (e.g., fences and

gates) that are currently associated with these areas and will remain after

these areas are released from licensing. Further, identify the type and

location of any new barriers or access points that will be established with

release of these areas.

Response

LTP Figure 2-1 shows the Industrial Area including the Industrial Area fence line.

Access to the Industrial Area is through the gate at the Personnel Access Portal (PAP)

building. The Industrial Area fence will remain in place after decommissioning is

completed.

There is also a fence, with a personnel gate and a vehicle gate, surrounding the ISFSI.

This fence will remain in place as long as the ISFSI is operational. Access to the ISFSI

also requires access to the Industrial Area.

Before the completion of the first phase of decommissioning, SMUD will construct a

fence, with gates for personnel and vehicle access, around the IOSB. Upon completion

of the first phase of decommissioning, the fence surrounding the IOSB will define the

10 CFR Part 50 licensed site until the completion of the second (last) phase of

decommissioning and termination of the 10 CFR Part 50 license.

c. Please clarify the location and approximate size (e.g., acres) of all

recreational areas in the vicinity of Rancho Seco and the approximate

distance from the Industrial Area. Include a listing of recreational activities, for

areas not already described. Please clarify the location of any water

recreation areas and their position along the hydrogradient (e.g., up-gradient,

April 2, 2007 Page 24 of 61
down-gradient) from the Industrial Area. A size estimate for Rancho Seco

Lake is already provided, but clarifications are needed regarding what

recreational activities take place at the lake.

Response

The land surrounding the Rancho Seco site is almost exclusively agricultural. The

hydrogradient of the site runs from northeast to southwest.

The Castle Oaks golf course, located in the city of lone, is approximately 10 miles east

of the site. The Dry Creek golf course, located in Gait, CA is approximately 10 miles

southwest of Rancho Seco and is down-gradient from the site. The Rancho Murieta

golf course is located approximately 10 miles north of the site.

A portion of Lake Camanche reservoir is approximately 10 miles southeast of the

Rancho Seco site. Lake Camanche covers 12 square miles, is 150 feet deep, and has

53 miles of shoreline when full. Both the North and South shore provide a variety of

recreational activities and services including tent and RV camping, cottage rentals, boat

rentals, boat launch, and fishing.

Lake Amador is approximately 13 miles east of Rancho Seco. The lake is

approximately 400 acres with approximately 13 1⁄2 miles of shoreline. Recreational

activities include tent and RV camping, boating, picnicking, and fishing.

Recreational activities at Rancho Seco Park include picnicking, tent and RV camping,

boating, fishing, and swimming. The park also has a 75-acre wildlife compound, located

just southwest of the lake's dam, and a seven-mile nature trail that starts at the north

end of the lake.

The nature trail is the product of a partnership between SMUD and The Nature

Conservancy. In 1999, The Nature Conservancy purchased 12,000 acres of the

Howard Ranch, which is located adjacent to Rancho Seco Lake. The conservancy

placed permanent protective restrictions on the property and resold the land to a local

cattleman, The Howard Ranch remains a working private cattle ranch.

The conservancy hired the California Conservation Corps to construct the trail, which

was opened to the public in June 2006. SMUD provides road access to the nature trail

as well as public parking at the trailhead. SMUD also provides ongoing maintenance on

the trail.

7. Sections 8.7.1, Federal Requirements, and 8.7.2, State and Local Requirements,

identify regulations, permits, licenses, notifications, and approvals that are in

place during decommissioning.

a. From these Sections, please provide a listing of local, State, and Federal

regulations that will continue during the period when only the IOSB remains

April 2, 2007 Page 25 of 61
on the NRC license, as well as, afterward, when the entire site is released

from the license.

Response

During the period when only the IOSB remains on the NRC 10 CFR Part 50

license and the ISOB remains under the 10 CFR Part 72 license, all of the

Federal, State and local requirements listed in Sections 8.7.1 and 8.7.2 will

continue to apply. When the entire site is released from both licenses, the NRC

requirements listed in Section 8.7.1.1 will no longer apply; however, the

Cal/OSHA and EPA requirements listed in Sections 8.7.1.2 and 8.7.1.3 and the

State and local requirements listed in Section 8.7.2 will continue to apply

because the site will be maintained as an industrial site.

b. The Federal Requirements listing indicates that Rancho Seco must comply

with the U.S. Environmental Protection Agency regulations for underground

storage tanks (Part 280 of 40 CFR). Please clarify whether any tanks will

remain on the site after the site is released from NRC licensing. If so, please

identify their past and, if applicable, continued use, as well as any

performance issues.

Response

There currently are no underground storage tanks on the Rancho Seco site and none

are planned to be added after the site is released from NRC licensing.

8. Section 8.5.1.3.3, Water Supply, identifies that potable water comes from four

wells and one well serves a residence located at the northeastern corner of the

site.

a. Please summarize plans for operation of the plant's water supply system with

release of the site from NRC licensing.

Response

The plant's water supply system will remain in operation after the release of the site

from NRC licensing.

b. Please specify the approximate distance between the current Industrial Area

fence and the residence located on the site.

Response

The distance between the Industrial Area fence and the residence located on the

Rancho Seco site is approximately 1 mile.

April 2, 2007 Page 26 of 61
IN SITU GAMMA SPECTROSCOPY ISSUES

General Discussion of In Situ Gamma Spectroscopy at Rancho Seco

There appears to be confusion over the use of in situ gamma spectroscopy at Rancho

Seco for final status survey (FSS). The system used is the Canberra ISOCS system

consisting of either HPGe or Nal detectors that have been characterized by the

manufacturer such that they can be accurately employed with any source geometry that

can be adequately described by the "geometry composer". Not only does this mean

that National Institute of Standards and Technology (NIST) traceable sources are not

required for every geometry used but it also means that a given spectrum can be

analyzed using multiple geometries with a high level of accuracy. It is this capability

that allows the spectrum collected from a large area to be analyzed as a small hot spot

at the edge of the field of view by directly comparing source activities rather than

efficiencies or some other parameter. This makes it simple to determine the ratio of the

small area source response to that of the large area source response. By establishing

the investigation level at the level of the elevated measurement comparison (EMC)

divided by the ratio of the two responses, an analytical result less than the investigation

criterion means that a small hot spot with an activity greater than the EMC value could

not be present within the field of view. This approach does assume the activity in the

hot spot and the large field of view is homogeneous, as does MARSSIM.

As stated in the referenced ORISE comments (ADAMS ML06360021) on in situ gamma

spectroscopy, MARSSIM does not consider discrete radioactive particles (DRPs).

There have been almost as many ways of dealing with DRPs as there have been

Decommissioning or License Termination Plans. Many LTPs made no mention of

particles at all (e.g., Trojan, Big Rock Point, and Hadem Neck ). The Shelwell site,

which underwent decommissioning outside of Columbus, Ohio in 1998, determined the

probability of finding a particle in a given 1 M2 ; determined the potential number of

particles per year that could be ingested or inhaled; and the resultant "expectation

dose". Maine Yankee and Yankee Rowe determined the sensitivity of their method of

walkover scan with respect to DRPs to be 1 uCi of Co-60. Meanwhile, the NRC has not

published the DRP sensitivity of the walkover scan described in NUREG-1 575 nor have

they determined an activity of DRP that is dose significant from the standpoint of

10 CFR Part 20.1402.

The decommissioning rule requires licensees to determine the potential annual dose to

the average member of the critical group. Of the few reference documents available

that discuss the dosimetry of DRPs, only NCRP-1 30, "Biological Effects and Exposure

Limits for Hot Particles", discusses the dose to the lung or GI tract from the inhalation or

ingestion of a DRP. NCRP-1 30 does not provide a dose per unit activity for either

inhalation or ingestion, it rather references the use of dose factors (such as those found

in Federal Guidance Report FGR-1 1) for the insoluble form of the particular

radionuclide. The report does stress that inhalation or ingestion is an extremely unlikely

event based on industry experience and the physical characteristics of DRPs. This is

further supported by an NRC "Regulatory Analysis of Revisions to 1 OCFR20 Unified

Skin Dose Limit October 2001" which stated that a survey of nuclear plant experience

April 2, 2007 Page 27 of 61
with DRPs showed that, of the 15,068 DRPs reported, only 0.2% involved both a skin

contamination and an activity of >1 uCi. Given the unlikely nature of an inhalation or

ingestion event and the very limited number of workers potentially exposed under the

industrial worker scenario, it seems unlikely that DRP internal exposure is a credible

scenario for the average member of the industrial worker group.

Because of the difficulties presented by DRPs, the emphasis for decommissioning is

placed on prevention and control measures. Each operating power plant developed a

"hot particle" control program that covered detection, prevention, control, and dosimetry

for DRPs. At Rancho Seco, that program is still being administered by the Radiation

Protection Group for decommissioning activities. Controls are established for

remediation of survey areas as necessary based on characterization data. During

structure remediation, both beta and gamma sensitive instruments are used to evaluate

the effectiveness of structure decontamination. Once it appears that residual activity is

less than the derived concentration guideline level (DCGL), areas are vacuumed, wiped

down, or otherwise cleaned prior to FSS. Before the final survey can begin, access

controls are established at the entrance to the survey area to prevent recontamination.

These measures make it highly unlikely that a DRP will be present in the survey area.

The likelihood of finding DRPs is greatest within Class 1 structures and least within

Class 3 soils. This means that the decontamination, detection, and control measures

are being applied to the proper areas. It also means that the lower in situ gamma

spectroscopy MDAs will be achieved in the areas where greater detection sensitivity is

desirable. Rancho Seco decommissioning technical basis document DTBD 06-003,

"Use of In Situ Gamma Spectroscopy for FSS," recommends the use of supplemental

Nal detector scans for soils with a high potential for DRPs (i.e., Class 1 soil). These

practices taken in total minimize the potential for significant undetected DRPs in FSS

areas.

Hot Particles

9.1 During a recent visit to the site, the NRC staff observed "Hot Particle" control

areas. Please provide a historical assessment of hot particles at Rancho Seco.

Please describe how your hot particle survey program relates to the remediation

and final status survey programs. Please provide a technical bases for the hot

particle detection program.

Response

While Rancho Seco has detected hot particles on site during its history, the

numbers and activities associated with the particles have not been as great as some

other facilities. The number of particles detected per year since decommissioning

1 The numbering of the "In Situ Gamma Spectroscopy Issues" RAIs has been revised to continue the

numbering sequence used for the "Environmental Issues" RAIs.

April 2, 2007 Page 28 of 61
began in 1990 is approximately 14 with an average activity of 0.013 pCi and a maximum

of 0.36 puCi.

Rancho Seco relies on Site Characterization to properly identify Class 1 areas, including

whether particles are present, and the Hot Particle Program to identify and control any

particles actually found. When these areas are ready for remediation, radiological

controls are established based on characterization data. These controls limit access

into and out of the areas; detect and control contamination sources, including DRPs if

necessary; and monitor remediation progress with repetitive surveys until the area is

ready for final survey. By the time the area is turned over for FSS it has undergone

multiple courses of decontamination and survey with many different types of survey

instruments to ensure it will meet the release criteria, including the EMC.

The hot particle controls observed by the NRC were put in place as a precaution given

the types of activities being performed at the time (e.g., vessel segmentation in the

reactor building, pipe decontamination in the Aux Building), not because large numbers

of particles have been recently detected. The presence of particles. in Class 2 and 3

areas is extremely unlikely as evidenced by the very low activity levels reported in those

FSS surveys. Particles are more likely to be found in Class 1 structures and on the soil

adjacent to them. These are the areas requiring more remediation and more surveys

with more than one type of instrument which increases the likelihood of detection if

particles are present.

The Hot Particle Program is covered in the attached procedure RP.305.09E, "Hot

Particle Controls". The Program described in procedure RP.305.09E is consistent with

similar programs used throughout the nuclear utility industry. The Program has been in

place for several years and has been successful in detecting and controlling particles as

part of the site Radiation Protection Program.

The technical basis for the Hot Particle Control Program used at Rancho Seco is the

same as that used throughout the nuclear industry. It.is based on the referenced

industry guidelines (viz., NRC IN 87-39, NRC IE Notice 86-23, and NRC IN 90-48) and

is used to detect, control and remove particles from FSS areas during the remediation

process. Its implementation ensures that when final surveys are performed there

should be no DRPs in the survey area just as there should be no significant areas

above the DCGL.

10. In DTBD-06-003, Rancho Seco identifies the method for determining the

Investigation Criteria. DTBD-06-003 states:

"Determination of the Investigation Criteria is based on taking a series of

measurements using the detector in a standard geometry, such as a disk,

located at a defined distance from the detector. The required geometry

parameters are entered into the geometry composer and the acquired spectra

area analyzed using the standard geometry. A new geometry is then developed

April 2, 2007 Page 29 of 61
which reduces the source to an area of I m 2 located at the periphery of the

detector field of view. The original spectra are then re-analyzed using the new,

small source area geometry. The ratio of the full field of view activity to the small

source activity is determined and the ratio is multiplied by the DCGLemc for a I m 2

area which becomes the Investigation Criterion."

How does Rancho Seco determine if the activity measured is uniform activity, a

hot particle, or a smaller area that exceeds the DCGLemc averaged over an area

less than 1 Mi2 ?

Response

The detailed investigation survey, performed following detection of an elevated area, is

the mechanism used to determine the size of the source causing the elevated reading.

In situ gamma spectroscopy is typically used to perform scan surveys of land and

structures. The purpose of the scan survey is to identify areas for further investigation

based on detecting an elevated measurement result. It doesn't matter whether the

elevated measurement is caused by a large area of uniform activity, a small area with

high activity or a discrete particle. As long as the measurement exceeds the

investigation criterion, the scan area will require further investigation to determine the

actual location, size, homogeneity, and level of activity responsible for the elevated

measurement.

11. DTBD-06-003 states, "It is anticipated that final surveys will typically be

performed with the detector at a distance of 2 m to 3 m from the source with a 90

degree collimator installed. This geometry defines a detector field of view (FOV)

of 12 m 2 to 28 mi2.'

What is the minimal detectable activity (MDA) using a 12 m2 FOV vs using a

28 m 2 FOV, assuming a hot particle is present in the FOV on soil and structure

surfaces, at a depth of 2 cm in concrete and at a depth of 15 cm in soil?

Response

Count times are established to achieve the required MDAs so there is no difference in

MDAs between either a 12 m2 FOV or a 28 m2 FOV. MDAs for soil are typically < 0.5

pCi/g and for structure surfaces are typically < 1,500 dpm/1 00 cm 2 . Scan

measurements are made using the "count to MDA" function which ensures that the

MDA achieved will meet the investigation criterion, however count times are usually in

the 600 to 1,000 second range. The table below shows the typical minimum particle

activities detectable for the geometries indicated based on actual MDAs for the given

FOV. The 2 cm depth for concrete structures refers to the possibility of contamination

slightly below the surface rather than a discrete particle embedded in concrete.

April 2, 2007 Page 30 of 61
MDAs For Particles With Various Geometries

ISOCS Geometry & FOV Particle Located In Particle Located At Edge* .Center

Soil Surface, 28 m2 < 0.4 uCi Co-60 < 1.1 uCi Co-60

Soil at 15 cm, 28 m2 1.7 uCi Co-60 4.3 uCi Co-60

Concrete Surface, 3 m2n 0.9 uCi Co-60 2.5 uCi Co-60

Containment Liner, 28 m2 1.4 uCi Co-60 3.6 uCi Co-60

The MDAs for Co-60 particles are presented because they are the most common

particle.

*The MDAs do not reflect the lower activities resulting from the overlapping fields of

view for Class 1 areas.

12. If such a hot particle exists, how does ISOCS determine its position in the FOV?

Response

As explained in RAI #10 above, the in situ scan measurement is not used to locate the

position of the elevated activity but rather is used to identify a scan grid for further

evaluation. The identified grid is investigated using a separate written survey plan that

may include the use of gas proportional detectors, Nal detectors, volumetric samples, or

additional in situ measurements with reduced fields of view. It is the investigation

measurements that identify the location, source and activity of the elevated reading.

13. Based on the MDAs for hot particles, what is the dose implication if such a hot

particle is present?

Response

For particles buried in soil, the direct dose from a 4 uCi particle of Co-60 for 2,000 hours

of exposure (based on the industrial worker scenario) at 100 cm is 1.2 mRem/y. The

detection methodology is more sensitive for particles on the soil surface and a I uCi

Co-60 particle for 2,000 hours of exposure at 100 cm would be 2.6 mRem/y. These

particles are easily detectable in the presence of underlying soil with little or no

significant activity above background (i.e., Class 2 and 3 survey units) and the total

dose would be less than 10 CFR Part 20, Subpart E limits.

Combining 2"x2" Nal scan surveys with in situ scans for Class 1 soil surveys ensures

that discrete particles of significant activity (i.e., greater than 1 uCi on the surface) would

be detected in order to meet 10 CFR Part 20, Subpart E limits.

April 2, 2007 Page 31 of 61
Discrete particle contaminations of personnel typically occur indoors. The indoor areas

are more likely to have discrete particles present prior to remediation and close

proximity to the particle is usually needed for a worker to become contaminated. The

performance of multiple surveys of structures during remediation and FSS make such

contamination events unlikely.

In Situ Gamma Systems at Rancho Seco

14.2 Please provide the technical bases that assures that the DCGL and elevated

concentrations do not exceed the depth of 15 cm of soil or 2 cm of surface on

structures? Please provide your bases for MDAs taking into consideration the

spatial and volumetric measurements you plan to make.

Response

The soil remediation techniques used and the post-remediation surveys conducted

ensure that FSS scans are only performed on a soil source depth of 15 cm. The in situ

geometry used for soil measurements is defined for a depth of 15 cm and the geometry

used for structures is defined for a depth of 2 cm or more. Volumetric samples are

taken at the prescribed depths to accurately determine the "as left" activity. Attached is

the revised DTBD 06-003, "Use of In Situ Gamma Spectroscopy for Final Site Survey",

which presents the MDAs and investigation criteria for homogeneous sources. The

"count to MDA" feature ensures that the MDA achieved is appropriate for the

investigation criterion of a given measurement, including consideration of DRPs, if

necessary. DTBD 06-003, Rev. 0 was previously submitted to the NRC with all

attachments. The attachments were not changed in Rev.1; therefore, the Rev. 1

without attachments is provided in Attachment 2.

15, Soil moisture can adversely impact the quality of ISOCS measurements. How

does Rancho Seco identify and adjust for soil moisture while using ISOCS?

Response

DTBD 06-003 describes the use of massimetric efficiency to reduce the impact of media

density or moisture effects. Soil scans are not performed during the rainy season

because of the difficulty of getting equipment into the field when the ground is very soft.

During the dry season, the ground has little residual moisture. With MDAs of 1 pCi/g or

less and DCGLs of 50 pCi/g, there is little effect on the scan evaluation even if soil

moisture induced an error of 10 to 15 percent. Furthermore, for soil surveys, the direct

measurements are typically volumetric soil samples that are dried and counted in the

laboratory which eliminates the moisture effect altogether.

2 The numbering of the "In Situ Gamma Systems at Rancho Seco" RAIs has been revised to continue the

numbering sequence from the "Hot Particles" RAIs.

April 2, 2007 Page 32 of 61
16. Describe how the proposed ISOCS measurements with the proposed FOV will

meet the DQOs for the FSS.

Response

The MDAs for in situ gamma spectroscopy are a very small fraction of the DCGLs for

either soil or concrete (less than 3.5%) and the use of conservative investigation criteria

ensure that elevated measurements are identified and investigated in order to

demonstrate compliance with the Elevated Measurements Criteria. This ensures that

the DQOs will be met.

17. How does Rancho Seco use the naturally occurring radionuclides that will be

identified in the ISOCS measurements to assure quality operations or to identify

equipment malfuntion?

Response

When the FSS Engineers review the in situ gamma spectroscopy results, they note the

presence of naturally-occurring radionuclides and whether the activity levels are

consistent with known site levels. They also note whether the reported photo peaks are

at the proper energy location within the spectrum and if the full width half maximum

(FWHM) values meet the analytical specification. These evaluations, coupled with the

daily pre- and post-QC source counts, ensure proper operation of the detectors.

OTHER

18.3 In Section 6.4.2, pg. 6-6. Rancho Seco identifies an "industrial worker scenario

for surface and subsurface soil exposures" for unrestricted release. It further

states in Section 6.4.2.1 that "...the public does not have ready access to the

remaining areas of the site". More specifically, please provide assurances as to

how RS will maintain these areas under the industrial worker scenario after the

first phase and after the second phase (See Section 8.3 Site Description After

Unrestricted Release, pg. 8-4). What mechanism will RS use to maintain these

areas as an industrial worker scenario?

Response

No controls are required to be implemented after license termination because Rancho

Seco is being decommissioned under 10 CFR Part 20.1402 for unrestricted release, not

under 10 CFR Part 20.1403 for license termination under restricted conditions.

3 The numbering of the "Other" RAIs has been revised to continue the numbering sequence from the "In

Situ Gamma Systems at Rancho Seco" RAIs.

April 2, 2007 Page 33 of 61
Justification for selection of an industrial worker scenario for surface and subsurface soil

exposures to use while performing dose modeling was provided in Section 6.4.2 of the

LTP. Section 6.4.2 concluded that it is reasonable to assume that the District will retain

ownership of the site for the foreseeable future and that members of the public will not

have ready access to Impacted Areas of the site. Section 6.8 of the LTP compared

alternative exposure scenarios for Impacted Area soils. Section 6.8.2 evaluated the

most conservative exposure scenario, the resident farmer scenario. Section 6.8.2

concluded that, after a period of approximately 30 years, Rancho Seco would comply

with the requirements of 10 CFR Part 20.1402 even under a resident farmer scenario.

Therefore, the foreseeable future only needs to consider a period of 30 years following

the first phase of license termination.

The entire 2,480 acres of SMUD owned property is surrounded by some type of fencing,

usually cattle fencing. The response to RAI No. 1.b. discusses the fate of the existing

Industrial Area during the foreseeable future. The fence enclosing the Industrial Area

will not be removed during decommissioning. Upon completion of the first phase of

license termination the Industrial Area will be maintained as an industrial site with

access controlled by the SMUD Asset Protection Department (industrial security). The

IOSB, which will remain under the 10 CFR Part 50 license until completion of the

second phase of license termination, will be contained within this industrial site. The

Backup Control Center in the Administration Building, the Training and Records Building

with occupied offices and the active switchyard will also be contained within this

industrial site. Upon completion of the second phase of license termination, access to

the industrial site will continue to be controlled by the SMUD Asset Protection

Department. This can reasonably be assumed to include at least a period of 30 years

following completion of the first phase of license termination.

SUPPLEMENTAL INFORMATION 4

The site reservoir (i.e., Rancho Seco Lake) was designed to supply emergency plant

cooling water in the event that water from Folsom South Canal was not available. The

lake is located approximately 2 miles southeast of the Industrial Area boundary.

The dam is under the jurisdiction of the State of California, Division of Dam Safety.

Accordingly, it is designed and constructed to standards established by the State of

California, which include consideration for earthquakes.

The probability of a sudden failure of an earth structure is very small. However, as part

of the original plant licensing, the effects on the plant of a dam failure or other sudden

release of water were evaluated. The analysis showed that an instantaneous break 50

feet wide, the full height of the dam, occurring simultaneously with the peak flow from

the design storm will not flood the plant site. The resulting flow would have had a water

surface that would have been more than 10 feet below any of the plant safety features.

4 Information requested during a March 19, 2007 conference call between NRC and Rancho Seco

personnel.

April 2, 2007 Page 34 of 61
Attachment 1

Hot Particle Controls Procedure RP.305.09E
Response to RAIs Dated February 27, 2007

MANUAL: RADIATION CONTROL MANUAL NUMBER: RP.305.09E

REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 1 OF 16

LEAD DEPARTMENT: EFFECTIVE DATE:

REVISION SUM61MARY:

1. Removed references to RP Responder.. RP Responder Program has been deleted.

2'. Added clarification to, "Prerequisites" section3. Added clarificalion to section 6.6.1 for RWP -equ~rements

4. Revised sec~nor on Hot Particle Control Exemptions. Deleted section on %Oýerations

activities., inspeciorns, and' I&C furnctios".

5. Revised secfion on Hot Partide survey requirernents for dariffcation..

April 2, 2007 Page 36 of 61
MANUAL: RADIATION CONTROL MANUAL NUMBER: RP.305.09E

REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 2 OF 16

PURPOSE

1.1. To proaide the Radiation Protection requirements for Hot Particle control,

assessment and responsee (COMMITMENT: Ref. 2-2.1).

2. REFERENCESI COMMITMENT rDOCUMENTS

2.1. Referen ces

2-.1. Title 10, Code of Federal Regulations, Part 20, Standards For

Protection Against Radiation

2.1.2- U.S. Nuclear Regulatory Informaton Notice, Numbfr 87-39, Control

of Hot Partcte Contamntination at Nuclear Power Plants2.1-3. U.S. Nuclear Regulatory IE Information Notice.., Number 86-23,

Excessive Skin Exposures Due To Contamination With Hot Particles.

2-1.4. U.S. Nuclear Regulatory Informaton Nbtice, Number 90-48,,

Enforcement Policy For Hot ParTicle- Exposures.

21.5. RP.305.D4,, Radiation Work Permits

2.1.6. RP.&U&.07, Area D,,finitions, Positng, and Requirements

21.7. RP.305.08A, Routine and Radiation Work Permit Surveys

2.1.8. RP.3D5..9A, Removal] of Tools and Equipment From Controlled

Areas

2.1.9. R-P.305.,19B, Personne~l Contamination Monitoringi

2-1-10. RP.3116.09C, Decontamination Procedures

2.1.11. RP.305.09D, Personnel and Clothing Decontamination and Reports

2.2. Commitment Documents

2.2.1. LER 88-003, Personnel O,,rerexposure Due to a Hot Particle

April 2, 2007 Page 37 of 61
MANUAL: RADIATION CONTROL MANUAL NUMBER: RP.305.09E

REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 31 OF 16

3. DEFIN'UTIONS

3.A. HOT PARTICLES - Highly radioactve (ac,,ty greater than 25,000 ccpn at

0.5 inches with an RM-14 equipped withi an: HP-260 probe or equivalent),

discrete., small particles of either irradiated' Fuel Fragments or neutron

acvatedl corrosion and wear products.

3.2. ZONE I - An area verified' to be free of Hoa Particles and unlikely to become

contaminated with Hot FPfrtcles3.3. ZONE 2 - HOT PARTICLE BUFFER ZONE - An area verified to, be free of

Hot Particles but havin.1 the potentia] of beconi~ng contaminated withi Hot

Particles.

3.4. ZONE 3 - HOT PARTICLE ZONE iHPZ) - An. area krov;wn or suspected to

contain Hot Particles.

4. PREREQUISITES

4.1. All persons entering Hot Particle Zones. shall be familiar wvith the Hot Particle

ControLs in effect in the area they are working in- Specitic info:rmatbn on Hot

Particle controus for vwork areas is listed on the. appilicable RWP for the area.

General information on Hot. Paricle controls is available from RP Supervision

and RP Technicians assigned coverage En the %ork areas.

5. PRECAUTI:ONS

5.1. Hot Partides, iidentified on personnel, must be tocated and renioved in: an

expeditious manner.

5.2. The RWP contains specific requirements for Hot Partite control,.

April 2, 2007 Page 38 of 61
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TITLE: HOT PARTICLE CONTROLS PAGE 4 OF 16

6. PROCEDURE.

INDEX

6.1 Establishrtn Hot Partice Zones

6.2 Posting Requiremrents For Hot Particle Zones

6.3 Hot Partitle SuTiwy Methods

6.4 Hot Particle Identifircation Techniques

6.5 Hot, Particle Survey Requirements

6.6 Hot Particle WoV Requiremients

6.7 Response to Hot Particle Detection O:utside• HPZs

6.8 Response to Hot Particles on PersonneO Outside HPZs

6.9 Response to Hot Particle 'Detection in an HPZ

6.10 Response to Hot, Particles on Personnel in an HPZ

6.11 Protective Clothing

6.12 Removal of Contaminateci Equipment from an HPZ

6.13 Persortnel Egress from Hot Particle Zones

6.14 Hot Particle, Trash

6.15 Deposting Hot Particle Zones

6.1. Establishinq Hot Particle Zones

6-1.1. IRP SuperAsion is responsible for establishing Hot Particle Zones

(HPZ) and implemanting Hot Particle controls.

61-.2. Establish HPZs for work in areas that meet either of th•e fo•wllting

criteria:

6.1.2.1. The area: or component is known toý be contaminated With

Hot Particles.

6.1.2.2. Work is perfomied in an area or on a component/system

that is suspected to contain Hot Particles based on previous

filndings of Hot Particles, or plant conditions.

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TITLE: HOT PARTICLE CONTROLS PAGE 5 OF 16

6.1.3. Review each job .rndidualy, tG determirnee the need for Hot Partcle

controls. Typical areas where Hot Particde controls may be

implemer•nte} include systems or components that have come into

direct contact with prinmary coolant, spent luet cooiant., or ftue

harndling eqipment.

6.1A.4 Areas with contaminaton levels greater than or equal! to 151,,6]00

dpnil( 1 cm2 are normally controlled as HPZs because it is difficult

to verify the absence of Hbt Partides.

6.A.5. At the discretion of RP Supervision, the follo,•1n activites andý

equipment are norn-mlly exempt from Hot Particle controls:

6.1.5.1. RP and Chemistry sampling: evolutions, samples, and

suirveys that do not require %,hlole body entry into a posted

HPZ.

6.1.5.2. C.osed, component internals such as Tygon tubing (or

equivalent), used to direct leakage to drains, unless workiing

on the component

6.2. Posting Requirements For Hot Particle Zones

NOTE

Hot Particle controls do not take the place of, NOR have more

importance than normal contaminaiton conirol requirements.

6.2.1. Post the HPZ and the Hot Particle Buffer Zone (Zone 2) En

accordance jith RP_305.07.

6.2.2- A phtysical barnter (i.e., herculite pen, railing, or wafl) around an HPZ,

eliminates the. requrement to establish a Hot Parfcle Buffer Zone.

6.2.3. Zone 1 areas are not required to beL specifically identified or postedl

April 2, 2007 Page 40 of 61
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TITLE: HOT PARTICLE CONTROLS PAGE 6 OF 16,

6.3. H-ot Particle Survey Methods

NOTE

KI is prudent to use tape to remove hot particte contani~nation from

vwrkers as surveys are performed..

6.3-1. Orect Survey

6.3.1.1. A direct survey refers to measuring clntaminatwn where ft

exists using a surey instrun-ent ar frisker6.3.1.2. A direct survey is preferred in the fo~lowing instances:

6.3.1.2.1. On personnell wh'n background tevells are not

restric@re

6.3.1.2.2. On irreg-ular surfa•es and for detecting 'fix~e Hot

Partidles ,(i.e., cracks and crevices)

6-3.1.2.3. When precise location of "parcle isdesired

6.3.1.3. A direct survey should be performed in a slow, deliberate

manner: tal.ing time to, cover all areas6.3.1.4. Perform direct surneys of p5ronel working, in an HPZ. if

possible. Survey the whole body, concentrating on areas of

the body that are suspect to. high• contamin,ation tevels, ike.,

hands, knees: feet:, etc., at the frequency specified in 6.5.5.

6.3.1.5. Identiied Hot Particles should be captured using tape,

masslinn. or si:ntilar method.

6.3.2. Indirect Survey

6.3.2.1. An indirect •urve• refers to measuring removed

contanminatbn us•inr, a wipe technique (massibnn,. tape: etc.).

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TITLE: HOT PARTICLE CONTROLS PAGE 7 OF 16,

6.3.2.2. An irndirect swuvey is preferred in the follmving instances:

6.3.2'.2.1. When covering large surface areas

6.3.2.2.2. To effectively pick up Hot Particles

6.3.2'.2.3. In high background areas to minimize time spent

in the area.

6.4. Iot Partide Identification Technigues

6.4.1. The described techniques apply to Hot Partides that have been

secured in nmaseftinn, tape, etc.

6.4.2. Lay the mas-slinn or tape out flat in a low background area and slbwvJy

frisk at a distance of 112 i.nch using an RM-141 HP-2119, or equiament,,

on fast response. IF the contamination ,evels are greater than

50,GDD ccprn, THEN a Ludlum-1TT, at 112 inch., OR an open ,w'ndow

RS-2, at a distance of I inch (from the source to the detector

vwndow)ý, may be used,.

6.4.3. IF areas, of significantly higher ac#vitb are found, THEN cut the

rnasslinn (or tape) into smaller pieces in order to, isolate the partice.

Refer to RP.305.09D for dose estimate nmethods.

6.4.3.1. Use a RP Badge, or material of equivalent demsity

thickness, as a shield between the Hot Particle and the

frisker probe or the open window RGL2.

6.4.3.2. IF the count/ dose rate decreases dramatically when

shielded, i.e., by 0t,%, THEN suspect a Co-60 crud particle.

6.4.3.3. IF the count dose rate does not, decrease dramnatically

when shield5d, i.e., less thran 5M, THEN suspect a Fuel

Fragmet.

6.4.4. Place the piece of material contai'ning the Hot Particle in a container

and seal the edges with tape. [ncI•ude date, time, and the appropriate

survey number or contamination report number.

6.4.5. Unless otherwise specified by RP Supervision, send the particle(s)

for isotopi~c analysis.

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TITLE: HOT PARTICLE CONTROLS PAGE 8 OF 16

6.5. Hot Partidle Survey Retuirements

6.5-1- HPZs are not required to be surveyed for Hot. Particles when no work

is being performed in that HPZ.

6-5.2. When no work is in progress in an HPZ,. survey areas for Hot

Particles at the follo,\ng f-equenci as a minminum:

6.5.2.1. Zone 1 areas and walktways at least weekly

6.5.2.2. Zone 2 (established buffer zone), prior to HPZ entry

6-5.3.. When Hot Particle work is in progress, survey all directly adjacent

Zone 1 andi Zone 2 areas once per shfft. Include step off peds in this

survey.

6.5.4- For vrk in an HPZ, perfom], Hot Particle surveys upon initiaD entry

and during work evolutions that may increase the potential' for

spreading Hot Particles.

6.5.5. Guidelines for performing peomnneJl Hot Particle Surveyss ,[sed on

the detected Hot Particle activity found using an RO-2 (open %indow

- closedv wndow, at i inch)] are:

6.5.5.1. Every 4 hours: <5 mR/hr

6.5.5.2. EveTy 2 houTs: 5 to t5 mR/hr

6.5.5.3. Once per hour (not to exceed 60 mi.): 16 to 30 mRJhr

6,5.5.4. Contact RP Supervision and evaluate

decontaminatng area.: >30 mR/hr

Note

For areas, wotich have detected• hot particle actity greater la

130 mR'hr,., decontamninating, the area should be constdered.

6.5.6- In areas where general area dose rates are very h5gh, i.e., hundreds

of nPRAr or greater, Hot Particles may be difficult to. detect- In these

instances, survey for Hot Particles per the guidance of RP

Supervision6.5.7. Document the performance of all Hot Particles surveys per

RP.30.:08.A and include the follmAng information:

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TITLE: HOT PARTICLE CONTROLS PAGE 9 OF 16

6.5.7.1. Whether or not Hot Particfes were found

6.5.7.2. GCPM or open vdindow minus closed window reading for

Hotl Particles detected

6.5.7.3. Frequency that personnel were surveyedl for Hot Particles, if

applicable

6.6. Hot Particie Work Requrenments

6-6-1. RWP Requirements:

6.6.1.1. A Radiation Work Permit (RWP), which allows work in a

HPZ, is requred for ag work perfomied in an HPZ in

accordance %%ith RP.305.04.

6-6-2- Continuous Radiation Protection coerage is required for aEl entries

into HPZs.

66.3. Ma r the RWP withi the words HOT PARTICLE CONTROLS in the

special instrucions block of the RIP. Special instructions wiBl be

tused to clarify Hot Particle Controls.

6-6-4- The normal frequency for surveying ,the personnel working in the

HPZ slhould not exceed: 4 hours. Specify the frequency in, the special

instructions block of the RWP.

6.6-5. Before starting work, a job briefing is required for RWPs that cover

work in HPZs.

6.6.5.1. The Hot Particte Job 8i:,efing should address., as a

minimum, the foiowing:

6.6.5.1.1. RWP requiraeents, and any speciall instructions

6.6.5.1.2'. Purpose of the periodic personnel surveys and

the expected job evolutions that may require

special surveys.

6.6.5.1.3. Response to di-covering or suspecting personnel

Hot Particle contandination

6.6.5.1.4. The proper undressing practices and sequence

to prevent personnel contanination.

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TITLE: HOT PARTICLE CONTROLS PAGE 10 OF 16

6.6.5.2. Document the required Enformation on a Hot Particle Briefing

Attendance Sheet, RAD-182 (Encdosure 8.1) by checking off

each item.

6.6.5.21 An ALARA Job Ptanning meeting can suffice for a Hot Partide Briefing,

6.6.5.3. Place the completed Hot, Particle Briefing Attendance Sheet

in the appropriate RWP File.

Note:

An ALARA Job Planning Meeting held and docunmented in

accordance with RP.3151.03, AALARA Job Plannring Guidelines"

may be substituted for the requirements of 6.6.5-2 and 6.6.5.3.

6.7. Responae to Hot Particle Detecfon Outside HPZs

6.7-1. Contain/ isolate the pa•rcle(s) and! measure dose! count rates-.

6.7.2. Stop wvork or traffic in the area, if necessary.

6.7.3. Notify RP Supervision6.7.4. Document required information on survey in accordance with Step

6.5.7 and send particles for analysis as. described in Steps 6.4.4 and

6.4.5.

6.7.5. Perform fol]owvup surveys in the affected area to determine the

extent of the Hot Particle problem.

6.7.6. RP Supervision ýWil determine the cause,, it possible, and ýniplement

corrective actions such as decontamination or increased survey

frequency, if necessary.

6.8. Response to Hot Partices on Personnel Outside HPZs

6.3.1- IE a Hot, Particle is. found on a person who has not been iin an HPZ,

THEN decontaminate the 5ndividual.

6.8.2. Notify RP Supe'vis ion.

6.8.3. Perform dose estinmates as required in accordance with RP.3[50.&9D.

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TITLE: HOT PARTICLE CONTROLS PAGE 11 OF 16

6.8.4. Evaluate the situation AUU perfomi follow up surveys to detemline

the extent of the problemn (i.e., survey the areas the contamninated

individuae had been in or walked through to see if more Hot Particfes

are present).

6.8.5. Document suirey information ;in accordance %ith Step 6.5-7 and

send particles for analisis p& Steps 6-4-4 and! 6.4.5.

6.9. Response to Hot Particle Detecton in an HPZ

6.9.1. IF Hot Particles greater than 30 mR/hr are found on equipatent or fn

the area, THEN isolate and' remove the parcIes to prevent worker

contaminriation.

6.9.2. Notify RP Supervision, who wirJ ealuate the need for

diecontamination.

6.9.3. Resurvey the affected area to deerenitine the extent of the problem.

6.9.4. Fol]ow guidrance in Section 6.10 if Hot: Particles are found on the

workers.

6.10. Response to Hot Partidles on Personnel in an HPZ

6.10.1. IF particles greater than 30 mR/hr [RO-2 (open vndow - closed

vrindow, at I1 inch)] are detected, THEN have the worker remove the

outer Bayer of Protective Clothing and exit the HPZ into Zone 2.

6.10.1.1. Surey the vurker's inner set of PCs to determine the

presence of Hot Partidles. IF Hot Paricles are foutnd or

suspected, THEN have the worker remove the remaining

PCs, cross the SOP to Zone, 1, AND proceed to a PCM-1 B.

6.10.1.2. IF Hot Parac!es are not found or suspected on! the inner

layer of PCs, THEN, the worker may don a new set of outer

PCs AND return to work.

6.10.1.3 Notify RP Supernsbon

6.10.2. IF a direct OR indirect sur•ey indicates less than 30 mReimhr on the

worker, THEN remove amy particles detected ANO the worker may

continue.

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TITLE: HOT PARTICLE CONTROLS PAGE 12. OF 16

6.11. Protecte Clothing

6.11-1 The following Protective Clothing may be used for performing work in an

HPZ. RP Supervndson will determiine the Protective Clothing requirements

for each job evoution.

6.11.1.1. Second, pair of outer coveralls (paper; charkate, plastic,

nylon), with all seanis taped (a second pair of cloth caeralls

may be allmowed for weldes),.

6.11.1.2. Second pair of rubber gloves taped to outer coveraols

6.11.1.3. Second hood,, securely taped to outer coveralls

6.11.1.4. Respirator taped to outer hood

6.11.1.5. Second pair of high-top booties taped to outer coveralls

and flats o'ver the second pair of high-top booties6.12'. Removal of Contamninated Eouipment from an HPZ.

6.12.1. Alli 'items leaing an HPZ should be wiped down with raisslinn, or

eqtuivalent or surveyed directiy for Hot Particles per Section 6.3.

6.12.2. IF no Hot Particles are found. .THEN handle items in accordance wth

RP.31)5.0gA.

612.3. Securely package items havtng, or suspected of having, Hot Particles

in a double bag, or similar equinpment:

6.12.3.1. Wipe down and survey the exterior of the first bag while in

the HPZ.

6.12.3.2. Place the first bag into the second ba in Zone 2. Survey

the exterior ofthe second bag to verify surfaces are free

from Hot Particles.

6.12.3.3. Use a "Jý seal, or simigar method, to ensure that no [nner

surtfaces, of the bags are accessible.

April 2, 2007 Page 47 of 61
NMANUAL: RADIATION CONTROL M'AANUAL NUMBER: RP.305.09E

REVISION: 4

TITLE: HOT PARTICLE CONITROLS PAGE 13 OF 16

6-12.4. Label the package to inctude at least the following Information (a

sticker may be used):

HOT PARTICLE

CONTACT mPRhr

DATE AND RP TECHNICIAN'S INITILALS

6.13. Personnell Egress from Hot Parlicle Zones

6-13-1. Carefully %%pe off any Respiratory Protection Equipment used,

remove outer Protective Clothing and respiratory equirnmnt, AND

cross the Step-Off Pad. A RP Technician (if available, see note

axove) should assist ýin the removal of Protect.•e Clothing.

6.13.2. Survey the persomel in accordance with Section 6.3.

6.13.2.1- IF no Hot Particles are found, THEN the workers should

exit the Hot Particle Buffer Zone.

6.13.2.2. IF Hot Partcltes are found, THEN follow the guidance of

Section 6.7.

6_13.3. Survey the removed Protective Clothing and Respiratory Protection

Equipment for Hot Particles.

6.13.3.1. IF no Hot Particles are found, THEN put the clothing and

resptratry equipment in, nomial receptacfes.

6.13.3.2. IF Hot Partctes are found, THEN, handle the tems in

accordance wth Steps 6.12.3 and 612A.

6.14. Hot Particle Trash

6.14-1. IF Not Particles are fou.nd, durring the job, THEN segregate the trash

as Hot Particle Trash and handle it, as follows:

April 2, 2007 Page 48 of 61
MTANUAL: RADIATION CONTROL M•ANUAL NUMBER: RP.305.09E

REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 14 OF 16

6.14.1.1. Survey the package per Sectbon 6-3.

6.14.1.2- Label the package per Step 6-12-3-

6.14.1.3. Store the package in a posted Hot Particle Trash Area.

6.14.1.4. Compact the! Hot Particle Trash separate4, from normal

radioactive trash using Hot Partide Contrdls.

6.14.2. IF Hot Particles are not fournd. THEN segregate trash per

RP.3a5.09A.

6.15. Deposting Hot Particle Zones

6.15.1- Before removing Hot Particle controls and depicsting an HPZ, RP

Supervision must evahrate the status of the work and work area to

determTne if the: Hot Particle controls can be downgraded.

6.15.2. I.F the potential source of hot Particles is contained, the HPZ is

surveyed per Step 6.3 ALfi no Hot Particles are found, THEN! the

area may be deposted from HPZ controls prior to continuation of

work in the area, with approval by RP Supervision6.15.3. Do not peform the evaluation vile work is being• prformed in the

area.

6.15-4. If this has not already been perfomied, survey Protective 0C1lothing,

any tools or euipment, trash containers, and bags for Hot Particles.

This may requEre removing the plasti:c bags from the barrels before

performing the surveys.

6.15-5. Document all] survey results per Step 6.5.7-

6.15-6- The approval for retease is to be noted on the RP Log, and ALARA

Job Tracking File (AJTF) as appropriate.

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REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 15 OF 16

7. RECORDS

7.1. The fblurAng indiWual! packagedl documenIs and re~ated correspondence

comprneted as a resuli of the perfom-ance or impl=ementatin of this pocedure

are records. They, shall be transnmifted to Reeords ManagemenI in

accordance with RSAP-rO&D1, Nuclear Records raa.rtg:snment.

7.t.1. Hot Partcle Briefing Attendance. Sheet

8. ENCLOSURES

8.1. Hot Particde Briefing Attendance Sheet (RA1D-182)

April 2, 2007 Page 50 of 61
MANUAL: RADIATION CONTROL MANUAL NUMBER: RP-305.09E

REVISION: 4

TITLE: HOT PARTICLE CONTROLS PAGE 16, OF 16

W~T M~T[CLE EIRIrWZNX AYTIUDAI SBUT

Tk(SK DE•RCHPrttO:

111o1CAraIM;

04S11IbICM PERfMflEII BY-' ___________

AMHP REQU[IDfNTS: ________

Pf(fIMIC PE MM1EL SLRVEY5. EXPFCTE SP'EM1L SURVEYS: ______

M"S[tM TO 0ISCOVEBF10 09 SUISPECTED HN~ PAWrTICIM$;_______

PADPEJA DRESSINGMURESI4IG PRNCTtI$ ________

BR.IEFIMG 05M'EMeS _________________________

WAD-1B2 Rev. D OFFM~rIVE DATE: %A*j,Vsq5* W 1frIc"

ENCLOSURE 8.1

PAGE 1 OF 1

April 2, 2007 Page 51 of 61
Attachment 2

DTBD 06-003, Rev. 2
Rancho Seco Nuclear Generating Station

Decommissioning Technical Basis Document

DTBD-06-003

Revision No. 1

DPT 06-036

RIC 2A.900

Use of In Situ Gamma Spectroscopy for Final Site Survey

PREPARED BY: G.D. Pillsbury

Author Date

REVIEWED BY:

Technical Reviewer Date

REVIEWED BY.

QA Reviewer Date

APPROVED BY:

Principal Radiological Engineer Date
1.0 Purpose

The purpose of this DTBD is to describe the use of in situ gamma

spectroscopy for performing final surveys.

2.0 Discussion

The intent is to employ a Canberra characterized HPGe detector (40% rel.

efficiency) coupled to an MCA using Canberra Genie software for

performing gamma spectrum analyses of various media for final site

surveys. Acquisition of a characterized detector allows the use of the

geometry composer software to model actual survey unit conditions in

order to obtain accurate gamma survey results. Use of the geometry

composer also allows the determination of investigation criteria which will

identify the possible presence of an elevated area of residual activity

within the detector field of view exceeding the EMC value for the survey

medium.

3.0 Definitions

Investigation criterion- An activity limit at which further evaluation of the

survey data is required. NUREG-1 575, Table 5.8, lists recommended

levels for survey unit investigation which are similar to those specified in

the RSNGS LTP. The investigation criteria used for in situ measurements

is based on preventing the EMC value in a 1 m2 area from being

exceeded; Because the criterion is a derived value rather than a simple

multiple of the DCGL, it can be thought of as an "effective" criterion.

4.0 Technical Position

In situ gamma spectroscopy can be effectively employed to perform final

surveys at MDCs comparable to those typically achieved with hand-held

instruments without the possibility of failing to detect an area of elevated

activity greater than the EMC value. The EMC value is applied to a 1 m 2

land area consistent with NUREG-1575 recommendations given the low

dose rates and the very large area factors associated with smaller areas.

In situ gamma spectroscopy can be used for any situation in which the

contaminant is a gamma emitter and the source geometry can be defined

by the geometry composer.

5.0 Limitations

This technical position can only be met using a characterized detector with

geometry composer software using approved procedures (Ref. 7.3) unless

geometry-specific, NIST traceable calibration sources equal to the size of

the detector field of view for each media are obtained. In situ gamma

spectroscopy may not be appropriate for performing soil scans in areas
with a risk of discrete particle contamination. Use of 2"x2" Nal detector

scans are recommended for this situation.

6.0 Technical Bases

Canberra has developed a HPGe detector which has been exposed to

gamma sources at multiple points in space in order to determine the

detector response to gamma photons which interact with the detector and

which originate from any location about the detector. The software uses

an iterative discrete ordinate attenuation computation routine to predict the

detector response when particular geometry features such as source to

detector distances, shielding materials, thickness of source or shield

materials, source and shield densities, source to detector angles, and

source configurations are entered into the geometry composer. These

features allow the same spectrum to be analyzed using more than one

geometry. It is this capability which makes possible the identification and

evaluation of hot spots using the investigation criterion.

A description and documentation of the characterization of the Canberra

HPGe detector (S/N 3920) is contained in Attachment 8.1.

It is anticipated that final surveys will typically be performed with the

detector at a distance of 2 m to 3 m from the source with the 90 degree

collimator installed. This geometry defines a detector field of view (FOV)

of 12 m2 to 28 M 2 . Due to the critical relationship of the geometries to the

analytical results, only approved geometries will be used for FSS surveys.

The gamma spectroscopy analysis report provides the total activity

detected within the field of view of the detector and reported in units of

pCi/g, pCi/m 2 or dpm/m 2. For spectra collected using the 90 degree

collimator, the FOV is the source to detector distance (which is equal to

the radius of the FOV) squared and multiplied by pi.

Concrete source activity depths will typically be set at 2 cm and soil

source activity depths will typically be set at 15 cm. These values are

consistent with site characterization experience and NUREG-1 575

assumptions. These source geometries allow for the collection of spectra

with MDA values for the nuclides of interest (i.e., Cs-1 37 and Co-60) at

approximately 0.3 pCi/g for soil and 500 to 1500 dpm/1 00 cm 2 for

concrete. Since the MDA values are three percent or less of the

respective DCGLs for soils and structure surfaces, the chances of making

a Type 1 error is less than 0.05 for reasonable count times of 20 to 60

minutes. The "count to MDA" feature of the Canberra software will be

employed to ensure that the desired MDAs are achieved.

Factors Affecting Detector Efficiency
Factors such as sample moisture content, soil density, and overlying water

could adversely impact detector efficiency. In situ gamma spectroscopy is

typically used as a scanmethod to detect areas of elevated activity, not for

direct measurement of soil activity to determine compliance with the

DCGLs. Soil density and moisture content don't have a significant effect

on scan results. However, the impact is further reduced by using the "massimetric efficiency" for analysis. Use of the "massimetric efficiency"

determines efficiency as c/m per unit activity per gram of sample. This

means that soil survey depths of 15 cm or more are seen as infinite and

soil density can vary by a factor of 2 with no impact on efficiency

according to Canberra "Model S573 ISOCS Calibration Software Manual"

(pgs. 163, 165).

The soil around the RSNGS site is extremely dry for most of the year. The

survey data sheets taken into the field by the survey techs are used to

document any standing water found in the scan area so that the geometry

can be adjusted to account for the shielding effect. Soil samples used for

direct measurements are sieved, dried, and weighed before counting in

the lab so their results are not impacted by moisture at all.

Furthermore, the analytical results of NORM in soil scans can be used to

identify possible impacts on efficiency so that the geometry can be

adjusted to account for such adverse effects. Typical indicator nuclides

are K-40 and Pb-212/214.

Investigation Criteria

Determination of the Investigation Criteria is based on taking a series of

measurements using the detector in a standard geometry, such as a disk,

located at a defined distance from the detector. The required geometry

parameters are entered into the geometry composer and the acquired

spectra are analyzed using the standard geometry. A new ?eometry is

then developed which reduces the source to an area of 1 m located at the

periphery of the detector field of view. The original spectra are then reanalyzed using the new, small source area geometry (Attachment 8.2).

The ratio of the full field of view activity to the small source activity is

determined and the ratio is multiplied by the DCGLEMC for a 1 m2 area

which becomes the Investigation Criterion. Any in situ measurement

which equals or exceeds the Investigation Criterion, when analyzed using

the full field of view geometry, requires further evaluation to rule out the

possibility of a small elevated area of activity within the detector field of

view.

For structure surveys, an initial geometry was constructed using a circular

plane with a source depth of 2 cm, a radius of 3 m and a source to

detector distance of 3 m. A series of spectra were collected using this

geometry with the 90 degree collimator attached to the detector. The
spectra were collected from a concrete wall with low, but detectable levels

of Cs-137 and Co-60. Analytical results were presented in pCi per m 2 and

Cs-1 37 data are shown converted to dpm/100 cm 2 in order to demonstrate

the sensitivity of the analyses (Co-60 was not converted due to higher

ambient levels of cobalt in the survey area and background was not

subtracted from any of the data).

Following the original analyses, the data were re-evaluated using a

geometry having a 2 cm thick source of 1 m2 placed at the periphery of the

field of view. The analytical results for the small area sources were

compared to the result for the large area sources (i.e., the 28 m 2 field of

view). The ratio of the small source to large source activity is the factor by

which the DCGLemc must be divided by to derive the Investigation

Criterion as shown in the table below.

Table 1. Geometry Comparison For Investigation Criteria

Sample #- Nuclide 28 m' source in 28 m2 1 m;' source in Ratio

FOV Geometry 28 m 2 FOV (Small to

pCi/ m2 dpm/100 Geometry Large)

cm2 pCi/m 2

CRC002 Cs-137 115684 2568 3058937 26.4

Co--60 922077 24604310 26.7

CRC003 Cs-1 37 30368 674 803012 26.4

Co-60 1182335 31550640 26.7

CRC004 Cs-1 37 84654 1879 2238500 26.4

Co-60 1176505 31394350 26.7

CRC005 Cs-137 646634 14355 17099200 26.4

Co-60 653756 17444690 26.7

CRC006 Cs-137 271698 6032 7184433 26.4

Co-60 708836 18915281 26.7

CRC007 Cs-137 54494 1210 1441027 26.4

Co-60 835538 22298770 26.7

CRC008 Cs-137 36151 803 955918 26.4

Co-60 640738 17097850 26.7

CRC009 Cs-1 37 26204 582 692930 26.4

Co-60 417889 11151050 26.7

CRC010 Cs-137 46540 1033 1230622 26.4

Co-60 1052418 28080790 26.7

CRC011 Cs-137 98584 2189 2606865 26.4

Co-60 965999 25775990 26.7

CRC012 Cs-137 298052 6617 7881140 26.4

Co-60 792048 21134200 26.7

CRC013 Cs-137 434564 9647 11491151 26.4

Co-60 1065999 28444600 26.7

CRC014 Cs-137 230746 5123 6101277 26.4
Co-60 456766. 12186860 26.7

CRC015 Cs-137 607692 13491 16068710 26.4

Co-60 393634 10504530 26.7

CRC016 Cs-1 37 356727 7919 9432931 26.4

Co-60 161815 4316970 26.7

CRC017 Cs-137 309195 6864 8175661 26.4

Co-60 313478 8364573 26.7

CRC018 Cs-137 156929 3484 4149533 26.4

Co-60 770318 20555180 26.7

CRC019 Cs-137 75953 1686 2008371 26.4

Co-60 1048337 27974780 26.7

Mean Cs dpm/100 cm2 4786 Mean Ratio 26.6

The gross beta-gamma DCGL for structures based on the established

nuclide fraction and conditions stated in DTBD 05-015 is 43,000 dpm/100

cm 2. Applying the area factor for a 1 m2 area of 14.9 results in a

DCGLemc of 640,700 dpm/100 cm 2 . The apparent geometry correction

factor for a 1 m 2 elevated area at the edge of the detector field of view of

28 m 2 is 26.6 as shown above. Dividing the DCGLemc value by the

geometry factor gives an Investigation Criterion of 24,000 dpm/100 cm 2 or

1.08E+6 pCi/mi2 or 3.04e+7 pCi in a 28 M2 field of view circular plane

geometry. This means that as long as the in situ gamma spectroscopy

result does not exceed 24,000 dpm/100 cm2 , there cannot be an

undetected elevated area within the field of view of 1 m2 which exceeds

the DCGLemc. Any analytical result greater than the Investigation

Criterion would require further evaluation to ensure compliance with the

EMC criterion. Investigation measures include, but are not limited to,

performing additional surveys using reduced source to detector distances,

scanning with 2" by 2" Nal detectors, collecting volumetric samples, or

other appropriate measures to detect small, elevated areas within the

original FOV. I

The data (Table 2) also indicate that the typical concrete surface MDAs for

a 1200 second count of 1318 dpm/100 cm for Cs-137 and 562 dpm/100

cm2 for Co-60 are a small fraction of the surface DCGL of 43,000 dpm/1 00

2

cm

Table 2. Concrete Surface 28 m 2 FOV MDA Values

Sample # Cs MDA (pCi/mi2 ) Co MDA (pCi/mi2)

CRC002 66400 23500

CRC003 64900 30300

CRC004 84700 35200

CRC005 60900 26800

CRC006 66600 25800

CRC007 50600 27900

CRC008 49800 20200
CRC009 47900 25000

CRC010 53600 27300

CRC011 56300 26200

CRC012 61800 21900

CRC013 74800 32900

CRC014 54600 18300

CRC015 50900 18100

CRC016 41100 20100

CRC017 52900 17900

CRC018 66500 28800

CRC019 64300 29500

Mean 59397 25317

dpm/100 cm2 1318 562

Soils have been surveyed using in situ gamma spectroscopy with a

geometry that evaluates soil activity to a depth of 15 cm over the detector

FOV. Soil Investigation Criteria have been determined (Table 3) in a

manner similar to that used for structures. The one square meter

DCGLEMc for Cs-137 would be 596 pCi/g for a DCGL of 52.8 pCi/g and an

area factor of 11.3 and for Co-60 would be 148 pCi/g for a DCGL of 12.6

pCi/g and an area factor of 11.8. The Investigation Criterion for Cs-1 37 is

23.6 pCi/g and for Co-60 is 5.7 pCi/g. The MDAs achievable are on the

order of 0.15 pCi/g for Cs-137 and Co-60 which is more than adequate for

the soil DCGLs at RSNGS. Investigation Criteria are established to

ensure the DCGLEMc will not go undetected in a small elevated area at

the edge of the FOV. Given the MDAs and Investigation Criteria for soil,

final surveys can be performed on soil with a Type 1 error of 0.05 using in

situ gamma spectroscopy for scans.

Table 3. Soil Geometry Comparison

Sample Nuclide 28 m2 source in 1 m2 source in Ratio (Small

# 28 m2 FOV 28 m2 FOV to Large)

Geometry Geometry (pCi/g) (pCi/g)

$3M005 Cs-1 37 0.376 9.517 25.31

Co-60 <0.220 <5.71 25.95

$3M006 Cs-137 0.480 12.155 25.32

Co-60 <0.152 <3.93 25.86

$3M007 Cs-1 37 0.310 7.842 25.30

Co-60 <0.129 <3.35 25.97

$3M008 Cs-137 0.288 7.298 25.34

Co-60 <0.143 <3.71 25.94

$3M009 Cs-137 0.319 8.072 25.30

Co-60 <0.148 <3.84 25.95

$3M010 Cs-137 <0.167 Obtained background

as a
Co-60 <0.138 count

S3M011 Cs-137 <0.143 3.624 25.34

Co-60 <0.142 <3.68 25.92

S3M012 Cs-137 0.431 10.923 25.34

Co-60 <0.137 <3.55 25.91

S3M013 Cs-137 0.411 10.412 25.33

Co-60 <0.153 <3.96 25.88

S3M014 Cs-137 0.273 6.910 25.31

Co-60 <0.142 <3.68 25.92

S3M015 Cs-137 0.468 11.841 25.30

Co-60 <0.135 <3.49 25.85

S3M017 Cs-137 0.554 14.018 25.30

Co-60 <0.148 <3.84 25.95

S3M018 Cs-137 0.372 9.416 25.31

Co-60 <0.161 <4.18 25.96

S3M019 Cs-137 0.376 9.527 25.34

Co-60 <0.176 <4.55 25.85

S3M020 Cs-137 0.435 10.022" 25.34

Co-60 <0.147 <3.81 25.92

Mean Cs-137 25.3

Co-60 25.9

As demonstrated above, in situ gamma spectroscopy can be employed for

performing final surveys with adequate sensitivity of analysis. For uses

not specifically described in this DTBD, a specific geometry (approved per

DSIP 0530) must be created, source to detector distances, use of

collimation and count times or required MDC must be specified to ensure

DQOs are met. When scanning, the MDC achieved must be shown to be

less than the DCGLEMc value for the survey unit. Since MDCs similar to

those achieved with lab instrumentation can be met with reasonable count

times, as long as the correct number of measurements are taken and any

adjustment for EMC criteria has been made, use of in situ gamma

spectroscopy should be able to achieve Type I and II errors of 0.05. The

use of Investigation Criteria ensure that small, elevated areas of activity

within the detector field of view will not go undetected or investigated.
7.0 References

7.1 DTBD 05-015, "Structure Nuclide Fractions and DCGLs".

7.2 DTBD 05-014, "Soil Nuclide Fractions and DCGLs".

7.3 DSIP 0530, "Operation of the ISOCS Portable Gamma

Spectroscopy System".

8.0 Attachments

8.1 ISOCS Detector Characterization

8.2 Concrete Surface Measurements for Determination of Investigation

Criteria

8.3 Soil Measurements for Determination of Investigation Criteria

9.0 RESPONSIBLE INDIVIDUAL

George Pillsbury