[ RadSafe ] 477 keV gamma in PWR RCS sample

[McGrath, Jack]

Dear all,

We have recently upgraded our gamma spectroscopy detectors to 45 percent germanium detectors.  We are performing analysis on our reactor coolant samples, and are observing a photopeak at 477 keV.

This sample was analyzed 4 days after sampling to remove short-lived interfering nuclides.

I have ruled out single, double escape and summation peaks

The following isotopes have been ruled out due to the absence of confirmatory lines.

E* (keV)

I* (%)

Parent

476.37 4

0.0363 22

166mHo<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=670466>

476.38 15

0.030 7

169Lu<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=710169>

476.40 5

0.0000015 5

186Re<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=750186>

476.49 5

0.023 3

205Bi<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=830205>

476.67 20

0.00010 2

115mCd<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=480415>

476.8 1

42.0 8

144Pm<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=610144>

476.827 6

0.32 4

200Tl<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=810200>

476.89 13

0.018 5

150Eu<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=630150>

477.0 6

0.009 6

153Tb<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=650153>

477.1 3

0.065 19

228Pa<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=910228>

477.2

0.00012

253Es<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=990253>

477.7 4

0.013 5

95Tc<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=430095>

477.75 4

0.094 9

151Pm<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=610151>

477.791 23

0.401 14

165Tm<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=690165>

477.8 3

1.82 21

190Ir<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=770190>

477.99 2

15

188Ir<http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=770188>




Does anyone have suggestions as to what the 477 kev is coming from?

Thanks!

Jack McGrath
Sr. Chemist
Ginna Station
Jack.McGrath at Constellation.com

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