L-MT-12-078, License Amendment Request: Modification to the MNGP Emergency Plan Concerning a Revision to the Emergency Action Level Setpoint for the Turbine Building Normal Waste Sump Monitor
| ML12356A473 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/21/2012 |
| From: | Schimmel M Northern States Power Co, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-MT-12-078 | |
| Download: ML12356A473 (18) | |
Text
@ . Xcel EnergyB Monticello Nuclear Generating Plant 2807 W County Road 75 Monticello, MN 55362 December 21,2012 L-MT-I2-078 10 CFR 50.90 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Monticello Nuclear Generating Plant Docket 50-263 Renewed Facility Operating License No. DPR-22 License Amendment Request: Modification to the MNGP Emergencv Plan Concerning a Revision to the Emergency Action Level Setpoint for the Turbine Building Normal Waste Sump Monitor Pursuant to 10 CFR 50.90, Northern States Power Company - Minnesota (NSPM),
doing business as Xcel Energy, Inc., proposes to revise the Monticello Nuclear Generating Plant (MNGP) Emergency Plan by revising the Emergency Action Level (RAI .2) setpoint for the Turbine Building Normal Waste Sump (radiation) Monitor. provides a description of the proposed changes and includes the technical evaluation and associated no significant hazards determination and environmental evaluation. Enclosure 2 provides a marked-up copy of the existing Emergency Action Level (EAL) and Basis pages indicating the proposed changes.
The MNGP Plant Operations Review Committee has reviewed this application. In accordance with 10 CFR 50.91, a copy of this application, with enclosures, is being provided to the designated Minnesota Official.
This license amendment request has been evaluated and has no impact on the pending Extended Power Uprate and Maximum Extended Load Line Limit Analysis Plus (MELLLA+) license amendment requests currently under NRC review.
NSPM requests approval of this proposed license amendment request by December 30, 2013, with the amendment being implemented within 120 days of U.S. Nuclear Regulatory Commission (NRC) approval.
Should you have questions regarding this letter, please contact Mr. Richard Loeffler at (763) 295-1247.
Document Control Desk L-MT-I2-078 Page 2 of 2 Summarv of Commitments This letter proposes no new commitments and does not revise any existing commitments.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on December 2 , 2 0 1 2 .
Mark A. Schimmel Site Vice President, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosures (2) cc: Administrator, Region Ill, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC Minnesota Department of Commerce
ENCLOSURE I MONTICELLO NUCLEAR GENERATING PLANT LICENSE AMENDMENT REQUEST MODIFICATION TO THE MNGP EMERGENCY PLAN CONCERNING A REVISION TO THE EMERGENCY ACTION LEVEL SETPOINT FOR THE TURBINE BUILDING NORMAL WASTE SUMP MONITOR DESCRIPTION OF CHANGES (11 pages follow)
TABLE OF CONTENTS SECTION TITLE PAGE 1.0
SUMMARY
DESCRIPTION 2.0 DETAILED DESCRIPTION 2.1 Proposed Change 2.2 Background
3.0 TECHNICAL EVALUATION
4.0 REGULATORY SAFETY ANALYSIS 4.1 Applicable Regulatorv Requirements 1 Criteria 4.2 Precedent 4.3 No Significant Hazards Consideration Determination 5.0 ENVIRONMENTAL EVALUATION
6.0 REFERENCES
L-MT-12-078 Enclosure 1 Page 1 of 10 MODIFICATION TO THE MNGP EMERGENCY PLAN CONCERNING A REVISION TO THE EMERGENCY ACTION LEVEL SETPOINT FOR THE TURBINE BUILDING NORMAL WASTE SUMP MONITOR DESCRIPTION OF CHANGES 1.0
SUMMARY
DESCRIPTION Pursuant to 10 CFR 50.90, Northern States Power Company - Minnesota (NSPM),
doing business as Xcel Energy, Inc., proposes to revise the Monticello Nuclear Generating Plant (MNGP) Emergency Plan by revising the Emergency Action Level (RAI .2) setpoint for the Turbine Building Normal Waste Sump (radiation) Monitor. The proposed change will approve the reduction of the threshold value for the Turbine Building Normal Waste Sump (TBNWS) Monitor to a new value of approximately 90 percent of the range of the monitor (i.e., 900,000 counts-per-minute (cpm)), which is approximately 48 times the Offsite Dose Calculation Manual (ODCM) alarm setpoint value.
2.0 DETAILED DESCRIPTION 2.1 Proposed Change A description of the proposed change to the TBNWS Monitor Emergency Action Level (EAL), i.e., RAI .2, is provided below together with a discussion of the justification for the change. The proposed wording for this monitor EAL (and basis document) which was developed previously, and for which approval is requested, is provided in Enclosure 2.
EAL RAI .2: The action level for escalation to the emergency classification Alert level due to liquid releases is revised from 200 times the ODCM alarm setpoint to 48 times the setpoint as indicated by the TBNWS (radiation) Monitor. A corresponding change to the Basis discussion is proposed to describe the basis for this revised action. This change to the EAL is appropriate because it will restore indication to within the capability of the applicable instrumentation and, based on this proposed action level, classification will be determined on a timely basis assuring the health and safety of the public is maintained.
This proposed change is acceptable because the MNGP Emergency Plan will continue to meet the requirements of 10 CFR 50 Appendix E and the planning standards of 10 CFR 50.47(b).
L-MT-12-078 Page 2 of 10 2.2 Background The current licensing basis for the MNGP EALs was established in early 2006. In October 2004, the Nuclear Management Company (NMC) submitted EAL changes for the MNGP (Reference 1) based on the EALs provided in Nuclear Energy Institute (NEI) 99-01 Revision 4, "Methodology for Development of Emergency Action LevelsJJ (Reference 2). U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.101, "Emergency Planning and Preparedness for Nuclear Power ReactorsJ' (Reference 3), identifies NEI 99-01 Revision 4 as an acceptable EAL scheme for compliance with 10 CFR 50.47(b)(4). The NRC reviewed the proposed EAL changes and approved them for implementation at MNGP by a Safety Evaluation (Reference 4) which became the current licensing basis for the MNGP EAL scheme.
Subsequent to implementing the revised EALs, the NSPM staff for the MNGP determined that the indication range (span) of the installed TBNWS (radiation) Monitor was insufficient to support the NEI 99-01 intended threshold value of 200 times the ODCM alarm setpoint value. This condition was documented in the corrective action program (CAP) for resolution. Similar issues have been identified at other plants,(') and has resulted in NRC findings. An interim compensatory measure was implemented at MNGP under the incorrectly interpreted provisions of 10 CFR 50.54(q) to revise the TBNWS Monitor setpoint to be reset to 90 percent of full scale without prior NRC review and approval.
Industry experience and a detailed EAL review for MNGP determined that changes were required to maintain compliance with the intent of the scheme as provided in NEI 99-01, the licensing basis for the current MNGP EALs. NSPM, applying the evaluation criteria provided in RG 1.219, "Guidance on Making Changes to Emergency Plans for Nuclear Power Reactors" (Reference 5), determined that the changes to resolve this issue should have been considered a "differenceJJ that would require prior NRC approval. A presubmittal conference call was held with the NRC, as recommended by RG 1.219, pertaining to EAL changes for the Prairie Island Nuclear Generating Plant (PINGP). Subsequently NSPM concluded that revision was also required to the TBNWS (radiation) Monitor setpoint, as described within this LAR, and required prior NRC review and approval.
As indicated above the proposed EAL change requested by this LAR, for which approval is requested, had been incorrectly incorporated (as an interim compensatory measure) into the MNGP Emergency Plan. Thus a markup of clarifying changes to the current TBNWS Monitor EAL and the new EAL Basis is provided. Since the current EAL is already in the final proposed form, the previously incorporated EAL and EAL Basis changes are indicated, since they are already in the MNGP Emergency Plan.
- 1. A review of operating experience indicated EALs associated with radiation monitors with setpoints exceeding full scale were ineffective. Based on this, a review was performed for the PINGP and subsequently MNGP EALs.
L-MT-I 2-078 Enclosure 1 Page3of 10 This LAR seeks to bring the change process for EAL into compliance with regulatory requirements and revise the EAL Basis to reflect the proposed change.
3.0 TECHNICAL EVALUATION
The current licensing basis for MNGP is in conformance with NEI 99-01 Revision 4, which was determined to be an acceptable EAL scheme by RG 1.I01 for compliance with 10 CFR 50.47(b)(4). The NRC has reviewed and approved the present EAL scheme for the MNGP (Reference 4).
EAL RAI .2 addresses effluent or accident radiation monitors on non-routine release pathways (i.e., those for which a discharge permit would not normally be prepared).
The MNGP ODCM establishes a methodology for determining effluent radiation monitor setpoints. The EAL scheme requires the values shown for each radiation monitor under the "Alert" column to be 200 hundred times the calculated ODCM release limits, unless an alternative value is authorized(*)and were determined using the ODCM methodology.
The effluent or accident radiation monitor setpoints, in this case the TBNWS Monitor setpoint, are established to ensure ODCM release limits are not exceeded for releases via these non-routine release pathways. The current EAL for the TBNWS Monitor (RAI .2) is based upon the NEI 99-01, Revision 4, classification scheme which requires escalation to an Alert emergency classification when a liquid release monitored by a radiation monitor indicates 200 times the ODCM alarm setpoint value for one of the specified radiation monitoring instruments for 15 minutes or longer.
However, as discussed previously, a review determined that the threshold value for the MNGP TBNWS Monitor was approximately 3.7 times greater than the range of the monitor. This was determined to be unacceptable since the installed TBNWS (radiation) Monitor cannot provide a reading for that radiation level, since it would be reading off-scale, and hence did not provide an acceptable basis for escalating the event classification. In 2010 a setpoint modification was made that established a new threshold value for the TBNWS Monitor of 90 percent of the range of the monitor, i.e., it was reset to the current value of 900,000 cpm. This setpoint correlates to 48 times the ODCM alarm setpoint.
This LAR requests the NRC authorize the revision of the TBNWS Monitor setpoint to require escalating the event classification to an Alert status when the TBNWS Monitor indicates 48 times the ODCM alarm setpoint value for 15 minutes or longer. Revising EAL RAI .2 to classify an Alert at 48 times the ODCM alarm setpoint ensures the classification can be performed within the current range of the installed radiation monitoring equipment.
- 2. The Stack Effluent Monitor setpoint for MNGP was approved by the NRC to be forty times the calculated ODCM release limit.
L-MT-12-078 Page 4 of 10 This proposed EAL change reduces the classification of a liquid effluent release via the Turbine Building normal waste sump pathway to approximately 48 times the ODCM limit from the current approved licensing bases of 200 times the ODCM limit. No other radiation monitor is available to assess the liquid effluent radioactive release condition from the Turbine Building normal waste sump pathway at 200 times the ODCM value.
Use of the TBNWS Monitor with a setting of 48 times the ODCM alarm setpoint maintains a clear delineation and escalation criteria for classification of and notification of an Unusual Event and an Alert. Classification of an Alert at 48 times the ODCM alarm setpoint value remains the most effective means of classifying an abnormal liquid release via the Turbine Building normal waste sump pathway.
Conclusion Changing the TBNWS Monitor setting EAL (RAI .2) will assure that the Emergency Plan is implemented in an effective and consistent manner. The EAL alarm setpoint value for classifying a liquid effluent release via the Turbine Building normal waste sump pathway will be established at a value within the indication capability of the radiation monitor.
Use of the TBNWS Monitor at the proposed alarm setpoint value will provide for escalation of an event at an appropriate level for liquid releases through this pathway.
4.0 REGULATORY SAFETY ANALYSIS 4.1 Applicable Requ1atot-v Requirements 1 Criteria
- a. Discussion of Applicable 10 CFR 50, Appendix A, General Design Criteria and Plant Specific Principal Design Criteria MNGP was designed largely before the publishing of the 70 General Design Criteria (GDC) for Nuclear Power Plant Construction Permits proposed by the Atomic Energy Commission (AEC) for public comment in July 1967, and constructed prior to the 1971 publication of the 10 CFR 50, Appendix A, GDC.
As such, MNGP was not licensed to the Appendix A, GDC.
The MNGP USAR, Section 1.2, lists the Principal Design Criteria (PDC) for the design, construction and operation of the plant. MNGP USAR Appendix E provides a plant comparative evaluation to the 70 proposed AEC design criteria. It was concluded that the plant conforms to the intent of the GDC.
The applicable GDC and PDC associated with radiation monitoring instrumentation is discussed below.
L-MT-12-078 Enclosure I Page 5 of 10 PDC 1.2.1 - General Criteria
- b. The plant is designed in such a way that the release of radioactive materials to the environment is limited, so that the limits and guideline values of published regulations pertaining to the release of radioactive materials are not exceeded.
PDC 1.2.4 - Plant Containment
- e. The integrity of the complete plant containment system and such other associated engineered safeguards as may be necessary are designed and maintained so that offsite and Control Room operator doses resulting from postulated design basis accidents are below the values stated in 10 CFR 50.67.
The applicable 70 Draft AEC General Design Criteria (AEC-GDC) are:
Criterion 17 - Monitoring Radioactivitv Releases (Category B)
Means shall be provided for monitoring the containment atmosphere, the facility effluent discharge paths, and the facility environs, for radioactivity that could be released from normal operations, from anticipated transients, and from accident conditions.
- b. Title 10 Code of Federal Regulations 50.47(b):
(b) The onsite and, except as provided in paragraph (d) of this section, offsite emergency response plans for nuclear power reactors must meet the following standards:
(4) A standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee, and State and local response plans call for reliance on information provided by facility licensees for determinations of minimum initial offsite response measures.
The MNGP Emergency Plan includes a standard emergency classification and emergency action level scheme based on the industry standard NEI 99-01, Revision 4. This LAR proposes to modify the TBNWS Monitor setting EAL (RAI .2) to specifically reflect a scheme based upon the plant radiation monitor system and effluent parameters. EAL RAI .2 will be modified to base liquid effluent event actions on the TBNWS Monitor (radiation monitor) at 48 times the ODCM alarm setpoint value. With this change, the Emergency Plan
L-MT-12-078 Page 6 of 10 will continue to invoke a standard emergency classification and action level scheme consistent with the plant design and ability to measure effluent parameters. Thus with the proposed change to the TBNWS Monitor described within this LAR, the requirements of 10 CFR 50.47(b) continue to be met.
- c. Title 10 Code of Federal Regulations Pad 50 Appendix E IV. Content of Emergency Plans
- 1. The applicant's emergency plans shall contain, but not necessarily be limited to, information needed to demonstrate compliance with the elements set forth below, ire., organization for coping with radiological emergencies, assessment actions ...
B. Assessment Actions
- 1. The means to be used for determining the magnitude of, and for continually assessing the impact of, the release of radioactive materials shall be described, including emergency action levels that are to be used as criteria for determining the need for notification and participation of local and State agencies, the Commission, and other Federal agencies, and the emergency action levels that are to be used for determining when and what type of protective measures should be considered within and outside the site boundary to protect health and safety. The emergency action levels shall be based on in-plant conditions and instrumentation in addition to onsite and offsite monitoring.
The MNGP Emergency Plan includes means for determining the magnitude of, and for continually assessing the impact of the release of radioactive materials, including emergency actions levels that provide the criteria for determining the need for notification and participation of governmental agencies and protective measures. This LAR proposes to modify the TBNWS Monitor EAL (RAI .2) to specifically base the actions on in-plant conditions and instrumentation. EAL RAI .2 will be modified to base liquid effluent event actions on in-plant radiation monitor indications at 48 times the ODCM alarm setpoint value. With this change, the Emergency Plan will continue to provide the means for determining the magnitude of the release of radioactive material and include emergency actions levels that provide criteria for notification of governmental agencies and determining protective measures. This emergency action level continues to be based on in-plant conditions, instrumentation and onsite monitoring. Thus with the change proposed in this LAR, the requirements of 10 CFR 50 Appendix E continue to be met.
L-MT-12-078 Enclosure 1 Page 7 of 10 4.2 Precedent NSPM is aware of two LARs which propose EAL changes. On April 27,2012, Omaha Public Power District submitted an LAR for Fort Calhoun Station, Unit 1 (Reference 6) which proposed to revise emergency action levels for flooding. On April 30, 2012, NextEra Energy Seabrook, LLC, submitted an LAR for Seabrook Station, Unit 1 (Reference 7) which proposed to revise EALs for classifications based on instrumentation failures. Since the requirement to request EAL changes as an LAR was established less than one year ago, NSPM is not aware of any such LARs that have been reviewed and approved by the NRC.
4.3 No Significant Hazards Consideration Determination In accordance with the requirements of 10 CFR 50.90, Northern States Power Company
- Minnesota (NSPM), doing business as Xcel Energy, Inc., requests an amendment to facility Renewed Operating License DPR-22, for the Monticello Nuclear Generating Plant (MNGP). The proposed change to the Emergency Plan is associated with the initiating condition for radioactive effluent monitoring via one pathway. The proposed change revise the emergency action level associated with the TBNWS Monitor to align with the capability of the installed instrumentation.
NSPM has evaluated the proposed amendment in accordance with 10 CFR 50.91 against the standards in 10 CFR 50.92 and has determined that the operation of the MNGP in accordance with the proposed amendment presents no significant hazards.
NSPM's evaluation against each of the criteria in 10 CFR 50.92 follows.
- 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The proposed change to the emergency plan does not impact the physical function of plant structures, systems, or components (SSCs) or the manner in which SSCs perform their design function. The proposed change neither adversely affect accident initiators or precursors, nor alter design assumptions. The proposed change does not alter or prevent the ability of operable SSCs to perform their intended function to mitigate the consequences of an initiating event within assumed acceptance limits. No operating procedures or administrative controls that function to prevent or mitigate accidents are affected by the proposed change.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
L-MT-12-078 Page8of 10
- 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No.
The proposed change does not impact the accident analysis. The change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed), a change in the method of plant operation, or new operator actions.
The proposed change will not introduce failure modes that could result in a new accident, and the change does not alter assumptions made in the safety analysis.
The proposed change revise an emergency action level (EAL), which establish the thresholds for placing the plant in an emergency classification. EALs are not initiators of any accidents.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed change involve a significant reduction in a margin of safety?
Response: No.
Margin of safety is associated with confidence in the ability of the fission product barriers (i.e., fuel cladding, reactor coolant system pressure boundary, and containment structure) to limit the level of radiation dose to the public. The proposed change is associated with the EALs and does not impact operation of the plant or its response to transients or accidents. The change does not affect the TSs or the operating license. The proposed change does not involve a change in the method of plant operation, and no accident analyses will be affected by the proposed change.
Additionally, the proposed change will not relax any criteria used to establish safety limits and will not relax any safety system settings. The safety analysis acceptance criteria are not affected by this change. The proposed changes will not result in plant operation in a configuration outside the design basis. The proposed change does not adversely affect systems that respond to safely shutdown the plant and to maintain the plant in a safe shutdown condition.
The revised EAL provides more appropriate and accurate criteria for determining protective measures that should be considered within and outside the site boundary to protect health and safety. The emergency plan will continue to activate an emergency response commensurate with the extent of degradation of plant safety.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
L-MT-12-078 Enclosure I Page9of 10 Based on the above, the NSPM has determined that operation of the facility in accordance with the proposed change does not involve a significant hazards consideration as defined in 10 CFR 50.92(c), in that it does not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
5.0 ENVIRONMENTAL EVALUATION The NSPM has determined that the proposed change would not revise a requirement with respect to installation or use of a facility or component located within the restricted area, as defined in 10 CFR 20, nor would it change an inspection or surveillance requirement. The proposed amendment does not involve (i) a significant hazards consideration, or (ii) authorize a significant change in the types or a significant increase in the amounts of any effluent that may be released offsite, or (iii) result in a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for a categorical exclusion set forth in 10 CFR 51.22(~)(9).Therefore, NSPM concludes that pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.
L-MT-12-078 Page 10 of 10 REFERENCES Letter from Nuclear Management Company, LLC (NMC) to Nuclear Regulatory Commission (NRC), "Revision to Emergency Action Levels," dated October 22, 2004 (L-MT-04-066)
Nuclear Energy Institute (NEI) 99-01 Revision 4, "Methodology for Development of Emergency Action Levels," dated January 2003 (NUMARCINESP-007).
(ADAMS Accession Number ML041470131)
U.S. NRC Regulatory Guide 1.I 01, Revision 4, "Emergency Planning and Preparedness for Nuclear Power Reactors," dated July 2003.
Letter from NRC to NMC, "Monticello Nuclear Generating Plant, Unit No. I-Revision to Emergency Plan Emergency Action Levels (TAC No. MC5017),"
dated January 5, 2006.
U.S. NRC Regulatory Guide 1.219, "Guidance on Making Changes to Emergency Plans for Nuclear Power Reactors."
(ADAMS Accession Number ML102510560)
Letter from Omaha Public Power District (OPPD) to Nuclear Regulatory Commission (NRC), "License Amendment Request (LAR) 12-03, Proposed Change to Revise Operating Requirements for Technical Specification 2.16, River Level, and Establish Emergency Action Level Classification Criteria for External Flooding Events under the Radiological Emergency Response Plan for Fort Calhoun Station," dated April 27, 2012 (LIC-12-0056).
Letter from NextEra Energy Seabrook, LLC (NextEra) to Nuclear Regulatory Commission (NRC), "Proposed Changes to Seabrook Station Emergency Action Levels Regarding Safety System Indications," dated April 30, 2012 (LAR 12-01).
ENCLOSURE 2 MONTICELLO NUCLEAR GENERATING PLANT LICENSE AMENDMENT REQUEST MODIFICATION TO THE MNGP EMERGENCY PLAN CONCERNING A REVISION TO THE EMERGENCY ACTION LEVEL SETPOINT FOR THE TURBINE BUILDING NORMAL WASTE SUMP MONITOR MARKED-UP EAL PAGES (3 pages follow)
FIGURE 7.2 EAL Technical Basis Document (Rev. 8) (cont'd) - I Abnormal Rad Levels 1 Radiological Effluent RAI Initiating Condition ALERT--
Any UNPLANNED Release of Gaseous or Liquid Radioactivity to the Environment that Exceeds 200 Times the Off-site Dose Calculation Manual Limit for 15 Minutes or Longer.
Operating Mode Applicability: All Emergency Action Levels: (RAI .Ior R A I .2 or RAI .3)
RAI.l , VALID reading on any effluent monitor that exceeds' 200 times the alarm setpoint established by a current radioactivity discharge permit for 15 minutes or longer.
RAI..2. VALID reading on any of the following radiation monitors that exceeds the reading shown for 15 minutes or longer.
Monitor Alert I1 Gaseous Insert below. Stack Effluent Monitor 1.46E7 kiCilsec*
(Ch A or B)
" ** 48 times RB Vent Effluent Monitor 2.16E6 pCi/sec (Ch A or B) The TBNWS setpoint was calculated limit" previously changed from Liuuid 3,775,200 cpm to 900,000 Service Water 31,400 cps cpm as discussed within this LAR.
Discharge Canal Monitor 93,000 cps 900,000 cpm No change is required to TBNWS this value.
s ODCM calculated limit R A I .3. Confirmed sample analysis for gaseous or liquid release indicates concentrations or release rates, with a release duration of I 5 minutes or longer, in excess of 200 times ODCM limit.
Basis:
This IC addresses a potential or actual decrease in the level of safety of the plant as indicated by a radiological release that exceeds regulatory commitments for an extended period of time.
MNGP incorporates features intended to control the release of radioactive effluents to. the environment. Further, there are administrative controls established to prevent unintentional releases, or control and monitor intentional releases. These controls are located in the Off-site Dose Calculation Manual (ODCM). The occurrence of extended, uncontrolled radioactive releases to the environment is indicative of a degradation in these features andlor controls.
I
FIGURE 7.2 EAL Technical Basis Document (Rev. 8) (cont'd) - I Abnormal Rad Levels I Radiological ~ffiuent RA'l The ODCM multiples are specified in ICs RUI and RAI only to distinguish between non-emergency conditions, and from each other. While these multiples obviously correspond to an off-site dose or dose rate, the emphasis in classifying these events is the degradation in the level of safety of the plant, NOT the magnitude of the associated dose or dose rate.
Releases should not be prorated or averaged.
Using the NEI recommended scaling factor of 200X the ODCM limit for the Stack Effluent Monitor setpoint creates an overlap situation where the RAI set point would be greater than the R S I setpoint for this monitor. Because of this overlap, MNGP chose a scaling factor of 40X the ODCM limit for the Stack Effluent Monitor set point to provide proper and logical scaling and yet maintain separation between the RAI and RSI set points. This is necessary because the set points calculated for RAI are based upon a different calculation methodology and limit than the setpoints calculated for RSI. The factor of 40 represents 20 times the RU1 EAL setpoint for the Stack Effluent Monitor and, as described above, serves only to distinguish between non-emergency conditions, and from each other.
UNPLANNED, as used in this co.ntext, includes any release for which a radioactivity discharge permit was not prepared, or a rele'ase that exceeds the conditions (e.g., minimum dilution flow, maximum discharge flow, alarm setpoints, etc.) on the applicable permit. The Emergency Director should not wait until 15 minutes has elapsed, but should declare the event as soon as it is determined that the release duration has or will likely exceed 15 minutes. Also, if an ongoing i-elease is detected and the starting time for that release is unknown, the Emergency Director should, in the absence of data to the contrary, assume that the release has exceeded 15 minutes.
RAI .Iaddresses radioactivity monitor readings that exceed t radioactivity discharge permit.
release, or a continuous release to warn of a release that is not the ODCM setpoints in this m setpoint established by a spe RAI .2 is intended to address effluent cident radiation monitors on non-routine release pathways (i.e., for which a discharge t would not normally be prepared). The ODCM establishes a methodology for deter effluent radiation monitor setpoints. The ODCM specifies default source terms and, ous releases, prescribes the use of pre-determined annual average me in the most limiting downwind sector for showing compliance with the regulatory co . The values shown for each monitor under, column "Alert" are two hundred ti ulated ODCM release limits (with the exception of the Stack Effluent Monitor set forty times the calculated ODCM release limit and the TBNWS Monitor setpoi of the instruments full scale reading of I d were determined using this methodology. The setpoints are established M release limits are not exceeded.
' RAI .3 address releases that are detected by sample analyses, particularly on unmonitored of radioactive liquids into storm drains, heat exchanger Basis description information previously added as,described with in this LAR.
Ilarb
FIGURE 7.2 EAL Technical Basis Document (Rev. 8) (cont'd) 1 Abnormal Rad Levels I Radiological Effluent RAI RAI .Iand.RAl.2 directly correlate with the IC since annual average meteorology is required to be used in showing compliance with the ODCM and is used in calculating the alarm setpoints. The fundamental basis of this IC is NOT a dose or dose rate, but rather the degradation in the level of safety of the plant implied by the uncontrolled release.
Due to the uncertainty associated with meteorology, emergency'implementing procedures call for the timely performance of dose assessments using actual (real-time) meteorology in the event of a gaseous radioactivity release of this magnitude. The results of these assessments should be compared to the ICs RSI and RGI to determine if the event classification should be escalated.
MNGP Basis Reference(s):
- 1. Monticello Calculation CA 04-199, Methodology Used to Derive Radiation Monitor Readings for NEI 99-01 Rev. 4 EALs.
- 2. ODCM-01.01 Off-site Dose Calculation Manual