Radioactive waste inventory estimation of a research reactor for decommissioning scenario development

Figures & data

Figure 1. Horizontal and vertical plane views of KARTINI Reactor

Table 1. Clearance levels of some important radionuclides [9]

Nuclide	Half Life	Clearance Level (Bq/g)	Exemption Level* (Bq/g)
H-3	12.3 y	100	1.0E+06
C-14	5730 y	1.0	1.0E+04
Cl-36	301 y	1.0	1.0E+04
Mn-54	312.5 d	0.1	1.0E+01
Fe-55	2.7 y	1000	1.0E+04
Ni-59	76,000 y	100	1.0E+04
Co-60	5.3 y	0.1	1.0E+01
Ni-63	100.1 y	100	1.0E+05
Zn-65	243.9 d	0.1	1.0E+01
Eu-152	13.5 y	0.1	1.0E+01
Eu-154	8.6 y	0.1	1.0E+01

*Exemption determines a priori which practices and sources within practices may be freed from the requirements for practices on the basis of their meeting certain criteria [6,8].

Figure 2. Flow of calculations

Table 2. Material compositions in weight percentage

Core Grids, Beam Port, Core Support	Reflector	Thermal Column	Thermalizing Column	Rotary Specimen Rack	Beam Port Shields	Reactor Tank	Biological Shielding
Al: 95.35	Al: 10.27	Al: 7.812	Al: 8.551	Al: 84.47	C: 3E-04	Al: 98.97	O: 14.37
Cr: 0.3	Cr: 0.032	Cr: 0.025	Cr: 0.027	Cr: 2.528	Mn: 0.002	Cu: 0.05	C: 14.1
Cu: 0.1	Cu: 0.011	Cu: 8E-03	Cu: 9E-03	Cu: 0.089	P: 5E-04	Fe: 0.4	Si: 2.35
Fe: 0.4	Fe: 0.043	Fe: 0.033	Fe: 0.036	Fe: 6.773	S: 3E-04	Mg: 0.05	Ca: 2.82
Mg: 2.6	Mg: 0.28	Mg: 0.213	Mg: 0.233	Mg: 2.306	Si: 8E-03	Mn: 0.05	Al: 2.35
Mn: 0.5	Mn: 0.054	Mn: 0.041	Mn: 0.045	Mn: 0.466	Cr: 0.2	Si: 0.25	S: 11.28
Si: 0.4	Si: 0.043	Si: 0.033	Si: 0.036	Si: 0.439	Ni: 0.12	Ti: 0.03	Ba: 46.7
Ti: 0.15	Ti: 0.016	Ti: 0.012	Ti: 0.013	Ti: 0.133	N: 0.1	V: 0.05	Fe: 3
Zn: 0.2	Zn: 0.022	Zn: 0.016	Zn: 0.018	Zn: 0.177	Fe: 6E-01	Zn: 0.05	H: 3
	C: 89.226	C: 89.856	C: 90.519	C: 0.0034			Eu: 9E-07
		B: 1.942	B: 0.504	P: 0.005
				S: 0.003
				Ni: 1.357
				N: 1.131

Figure 3. Simplified scheme of operation history used in this calculation as the basic case

Table 3. Distribution of neutron flux (n/cm².s) [11]

No.	Segment	Thermal	Epithermal	Fast
1.	Core Grids	6.32E+11	1.80E+11	1.31E+11
2.	Reflector	2.24E+11	6.84E+11	3.45E+11
3.	Rotary Specimen Rack	1.51E+11	3.09E+10	1.63E+10
4.	Reactor Tank	5.76E+06	1.76E+06	8.16E+05
5.	Core Support	1.85E+10	1.95E+09	1.16E+09
6.	Longest Beam Port	4.27E+10	1.39E+10	9.65E+09
7.	Beam Port 1	2.51E+09	1.88E+08	6.61E+07
8.	Beam Port 2	2.31E+09	1.80E+08	6.58E+07
9.	Beam Port 3	4.28E+09	4.12E+08	1.55E+08
10.	Beam Port Shields	1.51E+07	4.16E+07	2.49E+07
11.	Thermalizing Column	5.50E+09	6.32E+08	1.86E+08
12.	Thermal Column	3.19E+09	4.10E+09	1.08E+09
13.	Foundation	2.04E+05	3.60E+05	1.87E+05
14.	Biological Shielding (Elevation 0–402 m Segment)	1.97E+05	6.32E+05	2.32E+05

Energy range (Thermal: 0.001 < E < 0.01 eV, Epithermal: 0.1 < E < 10² eV, Fast: 0.5 < E < 20 MeV)

Figure 4. Neutron flux distribution [11]

Table 4. Radioactive inventories and D/C in components 5 years after reactor shutdown

No.	Segment	Nuclide	Specific Activity (Bg/g)	D/C	No.	Segment	Nuclide	Specific Activity (Bg/g)	D/C
1	Core Grids (0.253 t)	Fe-55	2.02E+04	2.02E+01	7	Outer Beam Port (0.2 t)	Zn-65	2.82E-03	2.82E-02
		Ni-63	1.24E+02	1.24E+00			Ni-63	1.11E-03	1.11E-05
		Zn-65	9.61E+02	9.61E+03			Fe-55	1.14E-01	1.14E-04
		Mn-54	5.99E±00	5.99E±01			Σ	1.18E-01	2.94E-02
		Σ	2.25E+04	9.69E+03
2	Reflector (1 t)	C-14	1.68E+02	1.68E+02	8	Beam Port Shields -0.7	Co-60	1.48E+02	1.48E+03
		Zn-65	1.47E+01	1.47E+02			Fe-55	8.25E+01	8.25E-02
		Co-60	1.01E+01	1.01E+02			Ni-63	5.41E+01	5.41E-01
		Eu-152	1.10E+02	1.10E+03			C-14	1.41E+01	1.41E+01
		Eu-154	5.72E+00	5.72E+01			Mn-54	9.95E-02	9.95E-01
		H-3	1.44E+03	1.44E+01			Σ	3.00E+02	1.50E+03
		Cl-36	1.49E±01	1.49E±01
		Σ	1.01E+03	1.91E+03
3	Rotary Specimen Rack (0.06 t)	Co-60	2.89E+04	2.89E+05	9	Thermal Column (0.8 t)	C-14	7.03E-01	7.03E-01
		Fe-55	1.02E+05	1.02E+02			Zn-65	2.26E-01	2.26E+00
		Ni-63	6.46E+04	6.46E+02			Eu-152	1.07E+00	1.07E+01
		C-14	1.65E+04	1.65E+04			Eu-154	6.29E-02	6.29E-01
		Ni-59	6.15E+02	6.15E+00			Co-60	5.41E-01	5.41E+00
		Mn-54	1.56E+01	1.56E+02			H-3	1.29E+01	1.29E-01
		H-3	1.08E+02	1.08E+00			Σ	2.56E+01	1.99E+01
		Zn-65	1.25E±02	1.25E±03
		Σ	2.13E+05	3.08E+05
4	Reactor Tank (0.8)	Mn-54	3.56E-04	3.56E-03	10	Thermalizing Column	C-14	1.16E+00	1.16E+00
		Fe-55	1.65E-01	1.65E-04			Zn-65	4.19E-01	4.19E+00
		Σ	1.67E-01	1.57E-02			Eu-152	1.77E+00	1.77E+01
							Eu-154	1.03E-01	1.03E+00
							Co-60	8.92E-01	8.92E+00
							H-3	2.13E+01	2.13E-01
							Σ	4.39E+01	3.34E+01
5	Core Support (0.253 t)	Ni-63	3.38E+00	3.38E-02	11	Foundation (150.9 t)	Ba-133	6.04E-03	6.04E-03
		Zn-65	1.04E+01	1.04E+02			Fe-55	3.62E-03	3.62E-06
		Mn-54	9.08E-02	9.08E-01			Eu-152	1.99E-05	1.99E-04
		Fe-55	6.64E±02	6.64E-01			Co-60	1.02E-03	1.02E-02
		Σ	6.80E+02	1.05E+02			Σ	1.07E-02	1.64E-02
6	Inner Beam Port (0.07 t)	Ni-63	1.91E+00	1.91E-02	12	Biological Shielding (Elevation 0-402 m) (460.8 t)	Ba-133	2.01E-01	2.01E-01
		Zn-65	1.41E+01	1.41E+02			Fe-55	1.32E-01	1.32E-04
		Fe-55	5.96E±02	5.96E-01			Eu-152	6.89E-04	6.89E-03
		Σ	6.12E+02	1.41E+02			Co-60	3.33E-02	3.33E-01
							Σ	3.67E-01	5.42E-01

Figure 5. Distribution of Σ D/C in biological shielding segments

Figure 6. Operation history assumption

Table 5. Σ D/C calculated using lower (a) and higher (b) case of operation history

No.	Segment	(a)	(b)
1.	Core Grids	3.60E+03	1.00E+04
2.	Reflector	1.89E+03	2.29E+03
3.	Rotary Specimen Rack	2.89E+05	8.05E+04
4.	Reactor Tank	8.30E-03	1.89E-02
5.	Core Support	1.05E+02	2.86E+02
6.	Inner Beam Port	8.68E+01	2.33E+02
7.	Outer Beam Port	1.79E-02	4.84E-02
8.	Beam Port Shields	6.67E+02	1.60E+03
9.	Thermal Column	1.84E+01	2.21E+01
10.	Thermalizing Column	3.07E+01	3.72E+01
11.	Foundation	6.03E-03	1.73E-02
12.	Biological Shielding (Elevation 0–402 m Segment)	2.01E-01	5.62E-01

Table 6. Σ D/C calculated using lower and higher impurities

No.	Component	Σ D/C
		Lower Case	Higher Case
1.	Reflector	1.26E+03	2.56E+03
2.	Rotary Specimen Rack	1.49E+05	4.66E+05
3.	Thermal Column	1.35E+01	2.64E+01
4.	Thermalizing Column	2.27E+01	4.40E+01
5.	Beam Port Shields	6.52E+02	2.46E+03
6.	Foundation	5.87E-03	2.81E-02
7.	Biological Shielding (Elevation 0–402 m Segment)	1.95E-01	9.26E-01

Table 7. Weight of radioactive wastes at 5 years after reactor shutdown

Material	Weight of radioactive Waste (tons)		Dominant Radionuclides
	Activation	Contamination
Metal	0.8	1.8*	Co-60, C-14, Ni-63, Fe-55
Graphite	2.6	–	C-14, Eu-152, Co-60
Barite Concrete	25.9	–	Ba-133, Eu-152, Eu-154, Co-60
Total	31.1

* The weight of reactor tank and spent nuclear fuel liner.

Figure 7. Horizontal and vertical plane view of KARTINI reactor showing area of categorization

Figure 8. Radioactive concrete waste distribution map according to simple dismantling cutting line

Figure 9. Summary of radioactive waste weight at 5 years after reactor shutdown

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