ML090930086

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Final Status Survey Summary Report for July 17, 2008, Reactor Building Tendon Gallery, Survey Unit F8111591
ML090930086
Person / Time
Site: Rancho Seco
Issue date: 07/17/2008
From:
Sacramento Municipal Utility District (SMUD)
To:
NRC/FSME
Shared Package
ML090830613 List: ... further results
References
DPG 09-097
Download: ML090930086 (35)
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Text

Rancho Seco Final Status Survey Summary Report July 17, 2008 Reactor Building Tendon Gallery Survey Unit F8111591 Prepared By.(ZJ Date:

FSS Engineer Reviewed By.ý'W&

Date:

0\\16' 0

Lead FSS Engineer Approved By:

Date:

-6 0

Dismantlement Superintendent, Radiological

il FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8111591, Reactor Building Tendon Gallery Survey Unit

Description:

Operating History: The reinforced concrete structure contained the reactor and supporting systems. The building contained four main elevations. Residual radioactive material was known to be present on all levels of the interior of the building. Operating records and the HSA document several events with the potential for a release of radioactivity inside this structure. No events documenting exterior contamination were found.

Site Characterization: Direct measurements were made of each of the interior elevation surfaces as well as the exterior surfaces of the structure. These measurements confirmed the presence of plant-derived radionuclides. Direct measurements on the -27' elevation showed a mean gross activity level of 1,535,383 dpm/100 cm 2 and a maximum value of 8,134,000 dpm/100 cm 2. Direct measurements on the grade elevation showed a mean gross activity level of 201,670 dpm/100 cm 2 and a maximum value of 370,000 dpm/100 cm 2. Direct measurements on the +40' elevation showed a mean gross activity level of 51,521 dpm/100 cm2 and a maximum value of 99,150 dpm/100 cm 2. Direct measurements on the +60' elevation showed a mean gross activity level of 20,110' dpm/100 cm 2 and a maximum value of 46,660 dpm/100 cm2. Direct measurements on the exterior roof showed a mean gross activity level of 1,364 dpm/100 cm 2 and a maximum value of 1,571 dpm/100 cm 2. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior of the reactor building was determined to be a Class 1 area and the exterior was a Class 3.

HSA Events: HSA Report pg. 63.

Survey Unit Design Information:

The Survey Unit Design Parameters are presented in Table 1 below. The survey unit and measurement locations are depicted on the maps in Attachment 1. Direct measurement locations were randomly determined and 363 m2 were scanned for approximately 20%

coverage. Samples of removable contamination were collected at each direct measurement location. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.

Page 2 of 8 FSS Summary Report F8111591

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:

Survey Unit:

Class:

SU Area (m2):

Evaluator:

DCGL (dpm/100 cm2):

Area Factor:

Design DCGLemc (dpm/100 cm 2):

LBGR (dpm/ioo cm2):

Design Sigma (dpm/100 cm2):

Type I Error:

Type II Error:

Predominant Nuclide:

Sample Area (m2):

Scan Area (m2):

Scan Coverage (%):

Sign P:

Calculated Relative Shift:

Relative Shift Used:

N-Value:

Design N-Value + 20%:

Design Min Samples N:

Grid Spacing L:

F811 1591 3

1817 Gary Frank 43000 N/A N/A 21500 119 0.05 0.05 Cs-137 N/A Reactor Building Tendon Gallery Structure Surface LTP Table 5-4 Gross Activity DCGL Class 3 Class 3 Default = 50% DCGL Class 3 Class 3 Uses 3.0 if Relative Shift is

>3 NUREG-1575 Table 5-5 Class 3 Class,3 363 20%

1.645 1.645 0.99865 180.6 3

11 14 14 N/A Page 3 of 8 FSS Summary Report F8111591

Survey Results:

A total of 14 direct measurements were made in F8111591. The results including mean, median, standard deviation and range are shown in Table 2. All directmeasurements were less than the DCGL. None of the scan measurements indicated areas of elevated activity. Scan activity ranged from 1863 to 16682 dpm/100 cm 2, based on a surveyor efficiency of 0.5 and no background subtracted. Samples for removable surface activity were all less than 10% of the DCGL as shown in Table 3. Removable surface activity samples were counted for alpha activity and none was detected at the MDC shown in Table 2-1 of Attachment 2.

Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cm F8111591-CO001BD F8111591-CO002BD F8111591-CO003BD F8111591-CO004BD F8111591-CO005BD F8111591-CO006BD F8111591-CO007BD F8111591-CO008BD F8111591-CO009BD F8111591-CO01OBD F8111591-CO011BD F8111591 -CO01 2BD F8111591-CO013BD F8111591-CO014BD Mean:

Median:

Standard Deviation:

Range:

1390 1447 1338 1395 1406 1292 1499 1494 1608 1401 1758 1577 1629 1634 1491 1471 1 134 1292 -1t758 Page 4 of 8 FSS Summary Report F8111591

Table 3..Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2 )

F8111591 C0001 SM F8111591C0002SM F8111591C0003SM F8111591C0004SM F8111591 C0005SM F8111591 C0006SM F8111591 C0007SM F8111591 C0008SM F8111591C0009SM F8111591CO010SM F8111591CO01ISM F8111591CO012SM F8111591CO013SM F8111591CO014SM Mean:

Median:

Standard Deviation:

Ranqe:

-4.82

-4.82

-3.53

-2.24

-3.53

-3.53

-2.24

-3.53

-2.24

-2.24

-0.95

-4.82

-2.24 2.93

-2.7

-2.88 2

-4.82 to 2.93 Page 5 of 8 FSS Summary Report F8111591

Survey Unit Data Assessment:

The survey design required 14 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 4. The sample mean and median values were less than the DCGL. The sample standard deviation was greater than the design standard deviation but both values of sigma resulted in a relative shift greater than three (3), no. additional samples were required.

Page 6 of 8 FSS Summary Report F8111591

Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2):

N/A Ambient Background Used (dpm/100 cm 2):

N/A Average Ambient BKG = 0 Actual Direct Measurements (N):

14 Median (dpm/100 cm 2):

1471 Mean (dpm/100 cm 2):

1491 Direct Measurement Standard Deviation 134 (dpm/100 cm 2):

Total Standard Deviation (dpm/100 cm2):

134 Based on samples and backgrounds.

Maximum (dpm/100 cm 2):

1758 Material Type:

N/A Background Subtract Not Applied Sign Test Final N Value:

14 S+ Value:

14 Critical Value:

10 Sufficient Samples Collected:

Yes Maximum Value < DCGL:

Yes Median Value < DCGL:

Yes Mean Value < DCGL:

Yes Maximum Value < DCGLemc:

N/A Class 3 Total Standard Deviation <= Sigma:

Investigate All results <0.5 DCGL Pass the Sign Test?

Yes Reject the Null Hypothesis?

Yes Does the Survey Unit Pass All Criteria?

Investigate Survey Unit Passes Page 7 of 8 FSS Summary Report F8111591

Survey Unit Investigations and Results:

No investigations were required for either direct or scan measurements and no investigation results are reported.

ALARA Statement:

As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL, the ALARA criterion has been met.

Changes in Initial Survey Unit Assumptions:

The survey unit was designed as a Class 3 structure survey and the sample results are consistent with that classification. The variability of the survey results was greater than the characterization data used for survey design. However, no additional samples were required. No potential areas of elevated activity were detected.

==

Conclusion:==

The FSS of this survey unit was properly designed as a Class 3 survey based on Table 5-4 of the LTP. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. No direct measurements exceeded the DCGL of 43000 dpm/100 cm 2 and none of the removable surface activity measurements exceeded 10% of the DCGL. No investigations were required.

The direct measurement data support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and that the data quality objectives were met.

It is concluded that survey unit F8111591 meets the release criteria of 10CFR20.1402.

Page 8 of 8 FSS Summary Report F8111591 Maps July 17, 2008 Survey Unit F8111591

0 C-Tendon Gallery Floor Beta Scans/Beta Directs I.

56 - 1 meter Beta Scans (I~

W 270°

.Beta Direct location 14 is 1.76m from E 900 and 0.52m from Outside Wall Tendon Gallery Floor -48' Elev 2440.0 ft2 226.7m 2

F8111591 - M1

Tendon Gallery Section 1 00 North to 900 East Beta Scans 0

N Shaft E

00 1B 900 58 5960 Ni 62 63 64 65 66 6768 69 70 71

00.

F]

1 11 F7V

-17F7H

-1[1H0F7H F

37'-6" 66'-11" '

4'-9" N

E

___00 900 126 127 128 129 130 131 132 33 134 135 136 137 138 119 140 141 I

I1 102'-6"

-Il 00

'.D,.-

F 1115 '91 - M2A F81115

Tendon Gallery Section 2 90' East to 1800 South Beta Scans 0

E S

90.

Exterior Wall 180° 72 73 74 75 76 77 78 79 80 81

'82 83 84 85 86 87 88 89 90 F-P 1 R l7~

JR [1F 71F

]X

-1 1-K 1

1 73'-10"

-]

30'-6" 4'-10" E

S 900 Interior Wall 1800 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 F N N I-1[-1 F1-F 102'-6" 00

~F8111591

- M2B F8111591

Tendon Gallery Section 3 CQ South 180' to West 2700 JBeta Scans 0

S Shaft W

1800 3B 2700 9

9 92 93 94 95 96 97 98 99 100 101 102 1o3(o50 4 105 106 107 FI F1 1-1F J

-09 F

n

.ý 84'- 11" 24'-4 S

W 1800 2700 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 I N.D-n--I.F] F1 r,1 FN F] F] F]

NN F-1 U

N N I 102'-6" 00 F8111591 - M2?C

b Tendon Gallery Section 4 West 2700 to North 00 Beta Scans W

N 2700 0.

108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 HH H H 1K]

D -=HHH H

109'-2" W

N C

2700 00 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 lKI 102'-6" oI (I)

FR 111.5

- M2D F811159I V

0 F8111591 Tendon Gallery Ceiling Beta Directs Beta Direct 06 is 15.4m from N 0° to West and 1.04 from Outside Wall cj~

W 2700

-E 9Q01 It1 00 t11 S

1807 Tendon Gallery Reflected Ceiling -48' Elev 2402.0 ft2 223.2m2 F8111591 - M3

(tD 00 0

Shaft 1A cj~

21.

Shaft 3B 210 209Sf Shaft 3A Shaft 2A lTI 00 Tendon Gallery Access Shaft Floor Beta Grating Scans

-26'6' Elev 491.0 ft2 45.6m2 F8111591 - M4

(E~

0 k)

E C:

0

.-)

E C:

5-R Looking West Looking North Looking East Looking South Shaft 1A Beta Scans 1226 ft2 113.9 m2 00 F8111591 - M5

(D~

0 C

0 6?-6" D --

COD E

C:

0 0

-34'-6" Looking West Looking North Looking East Looking South

'-In 00 Shaft 1 B Beta Scans 1513 ft2 140.6 m2 F8111591 - M6

C) 0*

cc E

0 0

E C0v 0

(#2 Looking East Looking South Looking West Looking North Shaft 2A Beta Scans 1214 ft2 112.8 m2 (3O r1h 00O F8111591 - M7

Cf CD k) 0 k) a)

E 0

I cj~

-34'-6" Looking East Looking South Looking West Looking North Shaft 2B ISOCS/Beta Scans 1481.0 ft2 137.6m 2

IT1 F8111591 - M8

~0 0 ý CO E

C-0C-m)

E C'

CO C

00 8'

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-26'-6" Looking South Looking West Looking North Looking East Shaft 3A Beta Scans/Beta Direct 843 ft2 78.3m 2

00l 00 F8111591 - M9

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(D 0) 110 -+

105 100 --

95 90 85 80-75 -

70

-7 65 -

60 55 "

50 -

45 -!

40 -*

35 30 -

25 --

20 -*

15 -

10 -

5-0 5

F8111591 Tendon Gallery Beta Direct

!f l

f1l 1,10 N

Shaft 0"

1B E

90° Shaft 2B S

180' Shaft W

3R 270'

[

06 04 01 0

0 14 12 09 1

03 0

In N0ý Ceiling I Outside Wall Floor side Wall E

90, W

270' 771 1

1 1

1 1

1 1

1 1

1 2

2 2

2 2

0 5.00 205 0

50 50 5 5

0 0

5 5

0 0

5 50 5

0 5

0 5

0 5

05 05 0

5 0

5 F8111591 - M11

crc~

a ON 0

Tendon Gallery Section 1 0' North to 90' East Beta Direct N

Shaft 1B E

900 37'-6" 66'-11" Beta Direct 02 is 6.4m from E 900 0.63m from the floor N

E o

900 05 102'-6" Beta Direct 05 is 6.3m from E 90' 0.36m from the floor 1-t1 00 F8111591 -M 12A

Tendon Gallery Section 2 900 East to 1800 South Beta Directs C

E S

900 Exterior Wall 1800 3.6m 9.06m 04, 1.15m

~73'-10" 30'-6" 4'-10" SE S

900 Interior Wall 1680 1.4m 03 1003

_______________________0.9m 102'-6" It 00R11Rq

- M12B F8111*91

CD

.00 Tendon Gallery Section 3 South 1800 to West 2700 Beta Directs S

Shaft 1800 W

2700 1

102'-6" 0O 00q F8111591 - M 12C

~0 Tendon Gallery Section 4 West 2700 to North 00 Beta Directs W

2700 N

15.4m 00 W

2700 N

00 7

102'-6" 00 F811159 - M12D

(IQ 0

Tendon Gallery Floor Gamma Particle Scans Gamma background measurements are obtained every 360 clockwise starting with location 1 (North 00).

09GQ 2700 E

900 Starting at N 00 measure 10.4m around the inside wall for each gamma particle scan.

This equates to approximately 300 resulting in 24 scans.

Gamma Particle Scans 25 and 26 are performed in the sump area and will include surface scan and scan of the sumps and junctures.

06GD I Tendon Gallery Floor -48' Elev 02440.0 ft2 226.7m 2

F8111591 - M13 Instrumentation July 17, 2008 Survey Unit F8111591

Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No.

Model; Serial No.

(dpm/100 cm 2)

(dpm/100 cm 2 )

M2350; 203482 44-10; 211672 N/A 5.2pCi/g M2350; 203482 43-68B; 178510 433 1033 M2350; 149789 43-68B; 161415 433 1033 M2350; 175834 43-68B; 148634 433 1033 M2350; 193715 43-68B; 148630

.433 1033 Tennelec; 0401171 N/A 6 dpm a, 12 dpmf3 N/A Table 2-2. Investigation Criteria and DCGL Value Parameter dmluc (d pm/100 Cm2)

Investigation Criteria - Direct 21500 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8111591 Investigation July 17, 2008 Survey Unit F8111591 (none required)

Data Assessment July 17, 2008 Survey Unit F8111591

4 0

14J) 00 F8111591 Gross Activity Sample Results Quantile Plot DGGL = 43000 dpm/100cm2 C

2,000 1,800 1,600 1,400 1,200 1,000 800 600 400 200 0

1471 0

20 40 60 Percentile 80 100 I

  • Direct Measurements (dpm/100cm2) -

median -

- - 75th Percentile

- 50th Percentile

--l....,

-D 0A FBI 11591 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmlf00cmr A

0 41--

U)

Cn k-h 2000 1800 1600 o 1400 C

1200-Ea. 1000 -

o800 -

Ž 600-S4"00 -

200 -

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U U

U U

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U U

U U

U U

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Measurement Locations o

Gross Activity Average a

"+3StDev

-3StDev" 1891 1491 1 1090

(

4 F81 11 591 Gross Activity Frequency Plot 0

DCGL = 43000 dprn/1 00cm2 6

777UpenVau 7

m0 2

5 4

LL (I)

~3.

LO) 00l Bins -Upper End Value (dpm/1 00cm2)

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