ML17199Q740
| ML17199Q740 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/25/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17199Q703 | List: |
| References | |
| NUDOCS 8707100492 | |
| Download: ML17199Q740 (19) | |
Text
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
~
RELATING TO ACCEPTANCE OF THE OFFSITE DOSE CALCULATION MANUAL (ODCM)
UPDATED THROUGH REVISIONS 11 AND llA COMMONWEALTH EDISON DRESDEN NUCLEAR POWER STATION, UNITS N0.2 AND 3 DOCKET NOS. 50-237 AND 50-249
1.0 INTRODUCTION
On November 16, 1984 the staff issued Amendment Nos. 83 and 77 to Facility Operating License Nos. DPR-19 and DPR-25 for the Dresden Nuclear Power Station, Unit Nos. 2 and 3. The amendments incorporated the Radiological Effluent Technical Specifications (RETS) into the Dresden Technical Specifications (TS). Section 6.8 of the TS referenced an Offsite Dose Calculation Manual (ODCM) and prescribed the methods for its change.
2.0 EVALUATION The submittal cf a Dresden ODCM, Revision 6 dated March 1983, by Commonwealth Edison (CE) (licensee) received NRC approval by letter dated November 16, 1984 from J. A. Zwolinsky to the licensee. Several discrepancies found in the review of the submittal were, however, to be corrected in the next revision of the ODCM.
In accordance with Dresden Technical Specification 6.8 the licensee addressed these discrepancies in the Dresden Monthly Operating Report for May 1985 and submitted as Revision 11, a complete package of revised site specific pages for the Dresden ODCM.
In the Dresden Monthly Operating Report for July 8707100492 870625
.PQR ADDCK 05000237 P
PDR'
'-.~-
1986, CE submitted a revised table of the Environmental Radiological Monitoring Programs on four pages labelled Revisior1 llA and dated A~l 1986.
The Dresden ODCM, Revision 11, qated March 1985 has been reviewed for us by EG&G Idaho Incorporated (EG&G), as part of our technical assistance contract program.
The contractor's Technical Evaluation Report (TER), which is enclosed as Appendix D from EGG-PHY-7257, provides a technical evaluation of the compliance of the licensee's submittal.with NRC criteria. The staff has reviewed this report, and agrees with the evaluation that the Dresden ODCM, Revision 11, generally uses documented and approved methods that are consistent with the methodology and guidelines in NUREG-0133.
Several conunents should be made relative to the "exceptions" listed in the Conclusion Section of the contractor's TER.
The. licensee addressed several of these exceptions to NRC criteria in Attachment A to the ODCM Requirements Section submitted with the May 1985 Monthly Operating Report.
The staff accepts these responses of CE with the condition that the documentation outlined below be provided in the next revision to the ODCM.
- 1.
For the inhalation pathway calculation, the dose rate for an infant is used rather than that for a child.
Present staff understanding directs that the calculation of the limiting gaseous effluent dose rate corresponding to the inhalation pathway be made with respect to the thyroid of a child instead of an infant. The basis for this is that the dose rate due to the combination of the
3 -
breathing rate and the dose factor for a child is more restrictive than the dose rate due to the same combination for an infant.
On th~ther hand the licensee states that they used the infant in their calculation because their existing computer software was more readily changed to the infant parameter than to the child.
The staff accepts this operational deviation on the condition that the licensee commit to the following items in their ODCM:
- a.
A statement similar to the above that the dose rate due to a child is more restrictive than that to an infant and is the rate to be used for T.S. 3.8.A.1.b.
- b.
A statement similar to that in Attachment A to the May 1985 Monthly Operating Report as to why the licensee is-using the dose rate to an infant.
- c.
Incorporate a factor in the inhalation dose calculation to account for the lack of conservatism in the infant calcuiation.
- 2.
The water usage and fish consumption values are respectively one-half and one-tenth the values recommended in NUREG-0133.
Since the ODCM is a stand-alone document in support of the Technical Specifications, documentation should be included to support significant deviation from staff guidance.
In Attachment A to the May 1985 Monthly Operating Report the licensee states that the NRC staff allowe~the use of a fi~h consumption rate lower than that in NRC guidance because the fish population of the Illinois River is low. A copy of the staff letter or statement containing this agreement should be provided in the ODCM.
In addition, a cormnitment should be made to reevaluate periodically the parameters that led to the "low fish population" concept and the use of a value of 1/10 staff guidance.
On the basis of this reevaluation adjustments to this fraction should be made when appropriate.
Similarly, documentation of the staff approval of the i value of staff guidance for water consumption should be provided, or an explanation given in the text if such documentation is not readily available. In addition, periodic reevaluation and adjustment of these values should be made as in the case above.
- 3.
The dilution water flow rate used in the calculations is more than six times the maximum of 2.0 x 103 cfs allowed in NUREG-0133 for a two unit plant site.
The licensee should change the ODCM to use the value of 2.0 x 103 cfs or provide in the ODCM an explanation as to why the higher value should be used.
In suntnary,for Items 2 and 3 above for the liquid dose calculation of the Technical Specifications, the licensee should explain in the O[)jH the site specific rationale for any deviations from staff guidance values to show that the dose calculated for liquid effluent releases from Dresden is to a maximum exposed member of the public.
After receipt of the TER from the contractor, a copy of Revision llA to the Dresden ODCM was receivea by the staff for review. This revision, dated April 1986 and submitted in the July 1986 Monthly Operating Report, contained changes only to the Environmental Radiological Monitoring Program of Section 8.4 of the ODCM.
The staff has reviewed these pages of Revision llA and finds that they are also consistent with the methodology and guidelines of NUREG-0133.
3.0 CONCLUSION
S The Dresden ODCM, Revisions 11 and llA, updated through April 30, 1987, is an acceptable reference for use with Dresden TS 6.8. The changes incorporated in Revisions 11 and llA are in compliance with Dresden TS 6.8.B
Plant-Specific Background On behalf of Dresden Nuclear Power Station, the Commonwealth Edison Company (CECo) submitted a change to the CECo ODCM[4] in a Monthly Operating Report issued by the Licensee.[5]
The Licnsee is~ed Revision 11 to site-specific Sections 7.2 and 8.0 of the ODC~.
The Licensee's changes to the ODCM were transmitted to an independent review team at the Idaho National Engineering Laboratory (INEL) for*
review.
The ODCM review was conducted and the results and conclusions of the evaluation are presented in this supplement.
REVIEW C~ITERIA Review criteria for the ODCM were provided by the NRC in three documents:
NUREG-0472, RETS for PWRs[2]
NUREG-0473, RETS for BWRs[3]
NUREG-0133, Preparation of RETS for Nuclear Power Plants.[6]
In the ODCM review the* following NRC guidelines were also used:
"General Contents of the Offsite Dose Calculation Manual,"
Revision 1,(7] an~ Regulatory Guide 1.109.(8] The ODCM format is left to the Licensee and may be simplified by tables and grid printouts.
01-4
. EVALU~TION The Licensee has followed the method~logy of NUREG-0133(6] to determine the alarm and trip setpoints for the liquid and gaseous effluent monitors, which ensures that the.maximum permissible concen~tions (MPCs), as specified in 10 CFR 20,[9] will not be ~xceeded b~ discharges from various liquid or gaseous release points. There are four radioactive liquid effluent release pathways for the three-unit site: the Unit 2/3 radwaste discharge system, the Unit 2 service water system, the Unit 3 service water system, and the service water effl~ents from the Unit 1 chemical cleaning facility. There are five radioactive gaseous effluent release pathways for the three-unit site: radioactive gases from the Unit 1 main chimney, the Units 2/3 main chimney, the Units 2/3 reactor building ventilation exhaust stack, the Unit 1 radwaste building vent, and the Unit 1 chemical cleaning facility. The Licensee's method for setpoint calculations de~cribed in site-specific Section 8.0 of the ODCM is consistent with the guidelines of NUREG-0133.
The Licensee's ODCM contains the methods and calculational relationships that are used to compare the radioactivity concentrations in liquid effluents at the point of release to the 10 CFR Part 20 limits prior to the release and after the release.
The Licensee's ODCM states that noble gas discharges are assured to be within the NUREG-0473 dose rate limits by correctly determining the setpoints for the noble gas monitors.
The dose rate due to the release of I-131, tritium, and particulates with half-lives greater than eight days is assured to be within the NUREG-0473 limit of 1500 mrem per year by calculating the dose rate to any organ of an infant via the inhalation pathway due to the actual release using the highest calculated annual average relative concentration X/Q used for estimating dose to an individual.
However, Draft 7 11 of Revision 3 to NUREG-0473 identifies inhalation as the most limiting pathway with the child's thyroid as the critical organ instead of any organ of an infant.
01-5
Doses to a member of the public due to radionuclides identified in liquid effluents are calculated monthly to show compliance with 10 CFR 50 Appendix I. The Licensee identifies the fish and water consumption pathways for the dose calculations assuming the adult as the maximum exposed individual.
The water usage and fish consumption factors listed on page 7.2-1 of the Dresden ODCM are one-half and one-tenth the values recommended in NUREG-0133, respectively. The same values are included in the La Salle County Plant's ODCM and the CECo based the Dresden values for the fish consumption due to the low fish population in the Illinois River as stated on page 4.2-1 of the ODCM and the Licensee states the NRC agreed to a lower fish consumption rate for the Dresden plant.[10] The La* Salle and Dresden plants are each located on the Illinois River. Additionally, the dilution water flow rate on page 7.2-1 of the Dresden ODCM is 1.37x104 cfs which is 6.85 times the maximum of 2.ox103 cfs allowed in NUREG-0133 for a two unit plant (a comparable situation exists for the La Salle plant).
The 1.37xlo4 cfs value appears to be the flow rate of the Illinois River whi~h is the receiving body of water. Consequently, the dose is not to a maximum exposed member of the ~ublic because of the low consumption and high dilution values. Additionally, the bioaccumulation factor for phosphorus in Table 7-1-12 of the ODCM should be 3x103 instead of lxlOS pCi/kg per pCi/liter.
Doses resulting from the release of noble gases and radioiodines, tritium, and particulates with half lives greater than eight days are calculated monthly to show compliance with 10 CFR 50 Appendix I.
The highest calculated annual average relative concentrations for X/Q are used to calculate the maximum air doses.
The Licensee identifies the ingestion and inhalation pathways to calculate doses for the maximum exposed member in the infant and adult age groups and the ground exposure pathway for all age groups.
The dose calculation methodology in the ODCM due to radioacti~e gaseous effluents satisfies the relationships presented in NUREG-0133.
M~thodology, based on dose projections, to determine required use of the liquid and gaseous radwaste treatment systems is described in the ODCM.
The projections are based on the dose calculations for radioactive effluents which satisfies the relationships in NUREG-0133.
Dl-6
The ODCM contains simplified flow diagrams illustrating the treatment paths and the components of the radi~active liquid, gaseous, and solid waste management systems.
Methodology for demonstrating compliance to 40 CFR 190 is l&escribed in the ODCM.
The Licensee's RETS and the ODCM state the time period is over 12 consecutive months instead of over a calendar year which is permitted by Draft 7 11 to Revision 3 of NUREG-0473.
The Licensee's RETS and ODCM state that compliance to 40 CFR 190 will be demonstrated if the doses exceed the quarterly or annual dose limits of the Technical Specifications. This is a conservative requirement since Draft 7 11 to Revision 3 of NUREG-0473 requires compliance to be demonstrated when twice the quarterly or twice the annual dose limits are exceeded.
Specific parameters of distance and the direction sector from the centerline of a reactor and additional information have been provided for each and every sample location identified in RETS Environmental Monitoring Table 4.8-4. The data are contained in ODCM Table 8.4-1 and ODCM Figures 8.4-1, 8.4-2, and 8.4-3.
In summary, the Licensee's ODCM as revised uses documented and approved methods that are generally consistent with the methodology and guidance in NUREG-0133, and therefore is an acceptable reference.
01-7
CONCLUSIONS The licensee's Revision 11 to site specific Sections 7.2 and 8.0 in conjunction with Revision 11 to the generic ODCM for CECo uses documented and approved methods and are consistent with the criteria of NUREG-0133 with the following oxceptions:
o As described in Section 2.1.2.2 the dose rate due to'1-131, tritium, and particulates with greater than eight-day half lives is determined for any organ of an infant via the inhalation pathway.
The dose rate calculation should be made for the
- thyroid of a child via the inhalation pathway to be in agreement with Draft 7" of Revision 3 to NUREG-0473.
o Section 8.1 references Equations 2.9 and 2.10.
The references should be to Equations 2.6 and 2.7.
0 The water usage and fish consumption values are respectively one-half and one-tenth the values recommended in NUREG-0133.
o The bioaccumulation factor for P-32 in Table 7.1-12 should be 3xlo3 instead of lx105 pCi/kg per pCi/liter.
o The dilution water factors Fw and Ff listed on page 7.2-1 in Table 7.2-1 of the ODCM are larger than the NUREG-0133 recommended values.
01-8
REFERENCES
- 1. Title 10, Code of Federal Regulations, Part 50, Appendix I, "Numerical Guides for Design Objectives and Limiting Conditions for ~eration to Meet the Criterion, "As Low As Is Reasonably Achievable,' for Radioactive Material in Light-Water-Cooled Nuclear Power Reactor Effluents.
11
- 2.
U. S. Nuclear Regulatory Conunission, "Standard Radiological Effluent Technical Specifications for Pressurized Water Reactors," USNRC NUREG-0472, Revision 3, Draft 7 11, September 1982.
- 3.
"U. S. Nuclear Regulatory Conunission, "Standard Radiological Effluent Technical Specifications for Boiling Water Reactors," USNRC NUREG-0473, Revision 3, Draft 7 11
, September 1982.
- 4.
Letter from K. Licari (CECo) to D. Eisenhut (NRC),
Subject:
Offsite Dose Calculation Manual, April 26, 1985.
- 5.
Letter from D. J. Scott (CECo) to Director, Office of Inspection and Enforcement (NRC),
Subject:
Monthly Operating Report for May 1985, DJS LTR:85-646, June 1, 1985.
- 6.
U. S. Nuclear Regulatory Convnission, "Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants, A Guidance Manual for Users of Standard Technical Specifications, 11 USNRC NUREG-0133, October 1978.
- 7.
U. S. Nuclear Regulatory Conmission, "General Contents of the Offsite Dose Calculation Manual," USNRC Branch Technical Position, Revision 1, Radiological Assess~ent Branch, February 8, 1979.
01-9
- 8.
U. S. Nuclear Regulatory Commission, "Calculation of.Annual Doses to Man from Routine Releases of Rea~tor Effluents for the Purpose of Evaluating Compliance with 10 CFR 50, Appendix l, 11 USNRC Regulatory Guide 1.109, Rev. 1, October 1977.
~
- 9.
Title 10, Code of Federal Regulations, Part 20, "Standards for Protection Against Radiation."
- 10. Letter from D. J. Sc~tt {CECo) to Director, Office of Inspection and Enforce~e~t {NRC),
Subject:
Dresden Station Operating Data, DJS LTR:
85-646, June 1, 19a5.
01-10
Plant-Specific Background On behalf of Dresden Nuclear Power Station, the Commonwealth Edison Company (CECo} submitted a change to the CECo ODCM(4] in a Monthly Operating Report issued by the Licensee.[S] The Lic~nsee is~d Revision 11 to site-specific Sections 7.2 and 8.0 of the ODC~.
The Licensee's changes to the ODCM were transmitted to an independent review team at the Idaho National Engineering Laboratory (INEL} for*
review.
The ODCM review was conducted and the results and conclusions of the evaluation are presented in this supplement.
REVIEW CRITERIA Review criteria for the ODCM were provided by the NRC in three documents:
NUREG-0472, RETS for PWRs[2]
NUREG-0473, RETS for BWRs[3]
NUREG-0133, Preparation of RETS for Nuclear Power Plants.[6]
In the ODCM review the following NRC guidelines were also used:
General Contents of the Offsite Dose Calculation Manual,"
Revision 1,(7] an~ Regulatory Guide 1.109.(8] The ODCM format is left to the Licensee and may be simplified by tables and grid printouts.
01-4
. EVALU~TION
(
The Licensee has followed the method~logy of NUREG-0133[6] to determine the alarm and trip setpoints for the liquid and gaseous effluent
~
monitors, which ensures that the maximum permissible concentrations (MPCs), as specified in 10 CFR 20,(9] will not be ~xceeded b~ discharges from various liquid or gaseous release points. There are four radioactive liquid effluent release pathways for the three-unit site: the Unit 2/3 radwaste discharge system, the Unit 2 service water system, the Unit 3 service water system, and the service water effluents from the Unit 1 chemical c~eaning facility. There are five radioactive gaseous effluent release pathways for the three-unit site: radioactive gases from the Unit 1 main chimney, the Units 2/3 main chimney, the Units 2/3 reactor building venti1ation exhaust stack, the Unit 1 radwaste building vent, and the Unit 1 chemical cleaning facility. The Licensee's method for setpoint calculations described in site-specific Section 8.0 of the ODCM is consistent with the guidelines of NUREG-0133.
The Licensee's ODCM contains the methods and calculational relationships that are used to compare the radioactivity concentrations in liquid effluents at the point of release to the 10 CFR Part 20 limits prior to the release and after the release.
The Licensee's ODCM states that noble gas discharges are ass~red to be within the NUREG-0473 dose rate limits by correctly determining the setpoints for the noble gas monitors.
The dose rate due to the release of I-131, tritium, and particulates with half-lives greater than eight days is assured to be within the NUREG-0473 limit of 1500 mrem per year by calculating the dose rate to any organ of an infant via the inhalation pathway due to the actual release using the highest calculated annual average relative concentration X/Q used for estimating dose to an individual.
However, Draft 7 11 of Revision 3 to NUREG-0473 identifies inhalation as the most limiting pathway with the child's thyroid as the critical organ instead of any organ of an infant.
Dl-5
Doses to a member of the public due to radionuclides identified in liquid effluents are calculated monthly to show compliance with 10 CFR 50 Appendix I. The Licensee identifies the fish and water consumption pathways for the dose calculations assuming the adult as the maximum exposed individual.
The water usage and fish consumption factors list;ed on page 7.2-1 of the Dresden ODCM are one-half and one-tenth the values recommend~d in NUREG-0133, respectively.
The same values are included in the La Salle County Plant's ODCM and the CECo based the Dresden values for the fish consumption due to the low fish population in the Illinois River as stated on page 4.2-1 of the ODCM and the Licensee states the NRC agreed to a lower fish consumption rate for th~ Dresden plant.(10] The La* Salle and Dresden plants are each located on the Illinois River.
Additionally, the dilution water flow rate on page 7.2-1 of the Dresden ODCM is 1.37xlo4 cfs which is 6.85 times the maximum of 2.ox103 cfs allowed in NUREG-0133 for a two unit plant (a comparable situation exists for the La Salle plant). The 1.37xlo4 cfs value appears to be the flow rate of the Illinois River which is the receiving body of water. Consequently, the dose is not to a maximum exposed member of the public because of the low consumption and high dilution values. Additionally, the bioaccumulation factor for phosphorus in Table 7-1-12 of the ODCM should be 3x103 instead of lx105 pCi/kg per pCi/liter.
Doses resulting from the release of noble gases and radioiodines, tritium, and particulates with half lives greater than eight days are calculated monthly to show compliance with 10 CFR 50 Appendix I. The highest calculated annual average relative concentrations for X/Q are used to calculate the maximum air doses.
The Licensee identifies the ingestion and inhalation pathways to calculate doses for the maximum exposed member in the infant and adult age groups and the ground exposure pathway for all age groups.
The dose calculation methodology in the ODCM due to radioactive gaseous effluents satisfies the relationships presented in NUREG-0133.
Methodology, based on dose projections, to determine required use of the liquid and gaseous radwaste treatment systems is described in the ODCM.
The projections are based on the dose calculations for radioactive effluents which satisfies the relationships in NUREG-0133.
01-6
The ODCM contains simplified flow diagrams illustrating the treatment paths and the components of the radi~active liquid, gaseous, and solid waste management systems.
Methodology for demonstrating compliance to 40 CFR 190 is ~escribed in the ODCM.
The Licensee's RETS and the ODCM state the time period is over 12 consecutive months instead of over a calendar year which is permitted by Draft 7" to Revision 3 of NUREG-0473.
The Licensee's RETS and ODCM state that compliance to 40 CFR 190 will be demonstrated if the doses exceed the quarterly or annual dose limits of the Technical Specifications. This is a conservative requirement since Draft 7" to Revision 3 of NUREG-0473 requires compliance to be demonstrated when twice the quarterly or twice the annual dose limits are exceeded.
Specific parameters of distance and the direction sector from the centerline of a reactor and additional information have been provided for each and every sample Jocation identified in RETS Environmental Monitoring Table 4.8-4.
The data are contained in ODCM Table 8.4-1 and ODCM Figures 8.4-1, 8.4-2, and 8.4-3.
In summary, the Licensee's ODCM as revised uses documented and approved methods that are generally consistent with the methodo~ogy and guidance in NUREG-0133, and therefore is an acceptable reference.
01-7
.*:~~-
CONCLUSIONS The Licensee's Revision 11 to site specific Sections 7.2 and 8.0 in conjunction with Revision 11 to the generic ODCM for CECo uses documented and approved methods and are consistent with the criteria of NUREG-0133 with the following exceptions:
~
o As described in Section 2.1.2.2 the dose rate due to:I-131, tritium, and particulates with greater than eight-day half lives is determined for any organ of an infant via the inhalation pathway.
The dose rate calculation should be made f~r the
- thyroid of a child via the inhalation pathway to be in agreement with Draft 7" of Revision 3 to NUREG-0473.
o Section 8.1 references Equations 2.9 and 2.10.
The references should be to Equations 2.6 and 2.7.
0 0
The water usage and fish consumption values are respectively one~half and one-tenth the values recommended in NUREG-0133.
The bioaccumulation factor for P-32 in Table 7.1-12 should be 3xlo3 instead of lxlo5 pCi/kg per pCi/liter.
o The dilution water factors Fw and Ff listed on page 7.2-1 in Table 7.2-1 of the ODCM are larger than the NUREG-0133 recommended values.
01-8
REFERENCES
- 1. Title 10, Code of Federal Regulations, Part 50, Appendix I, "Numerical Guides for Design Objectives and Limiting Conditions forl&peration to Meet the Criterion, 'As Low As Is Reasonably Achievable,' for Radioactive Material in Light-Water-Cooled Nuclear Power Reactor Effluents.
11
- 2.
U.S. Nuclear Regulatory Conunission, "Standard Radiological Effluent Technical Specifications for Pressurized Water Reactors," USNRC NUREG-0472, Revision 3, Draft 7 11, September 1982.
- 3.
"U. S. Nuclear Regulatory Conunission, "Standard Radiological Effluent Technical Specifications for Boiling Water Reactors," USNRC NUREG-0473, Revision 3, Draft 7 11,
Septembe~ 1982.
- 4.
Letter from K. Licari (CECo) to D. Eisenhut (NRC),
Subject:
Offsite Dose Calculation Manual, April 26, 1985.
- 5.
Letter from D. J. Scott (CECo) to Director, Office of Inspection and Enforcement (NRC),
Subject:
Monthly Operating Report for May 1985, DJS LTR:85-646, June 1, 1985.
- 6.
U. S. Nuclear Regulatory Commission, "Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants, A Guidance Manual for Users of Standard Technical Specifications," USNRC NUREG-0133, October 1978.
- 7.
U. S. Nuclear Regulatory Commission, "General Contents of the Offsite Dose Calculation Manual," USNRC Branch Technical Position, Revision 1, Radiological Assessment Branch, February 8, 1979.
01-9
- 8.
U. S. Nuclear Regulatory Commission,* "Calculation of Annual Doses to Man from Routine Releases of Rea~tor Effluents for the Purpose of Evaluating Compliance with 10 CFR 50, Appendix l, 11 USNRC Regulatory Guide 1.109, Rev. 1, October 1977.
- 9.
Title 10, Code of Federal Regulations, Part 20, "Standards for Protection Against Radiation."
- 10. Letter from D. J. Scott {CECo) to Director, Office of Inspection and Enforce~ent {NRC),
Subject:
Dresden Station Operating Data, DJS LTR:
85-646, June 1, 1985.
Dl-10