ML20197C823
| ML20197C823 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 09/03/1998 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20197C802 | List: |
| References | |
| NUDOCS 9809140219 | |
| Download: ML20197C823 (13) | |
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,g NUCLEAR REGULATORY COMMISSION
't WASHINGTuN, D.C. 20555-0001
.... 4 SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF A REQUEST FOR EXEMPTION FROM CERTAIN 10 CFR PART 50 REQUIREMENTS FOR EMERGENCY PLANNING FOR THE MAINE YANKEE PLANT DOCKET NO. 50-309
1.0 INTRODUCTION
A By letter dated November 6,1997, Maine Yankee Atomic Power Company (MYAPCo or the licensee) requested an exemption from the requirements of 10 CFR 50.47(c)(2) and the requirement of 10 CFR 50.54(q) that emergency plans must meet all of the standards of 10 CFR 50.47(b) and all of the requirements of Appendix E to 10 CFR Part 50 and submitted a draft copy of the Defueled Emergency Plan (DEP) for the Maine Yankee Atomic Power Station (Maine Yankee), Docket No. 50-309. In a letter dated August 7,1997, MYAPCo submitted written certifications to the U.S. Nuclear Regulatory Commission (NRC or the Commission) that the Board of Directors of MYAPCo had decided to permanently cease operation at Maine Yankee and that fuel had been permanently removed from the reactor. In consideration of the shutdown and defueled status of the plant, the requested exemption from 10 CFR 50.54(q) would allow the licensee to discontinue offsite emergency planning activities and reduce the scope of onsite emergency planning. On March 25,1998, the licensee submitted the Emergency Action Levels it proposed to use with the DEP. In a letter dated June 29,1998, subsequent to conference calls held on June 16 and June 24,1998, the licensee made changes to its exemption request. By letters dated July 9 and August 3,1998, the licensee provided the results of radiological analyses applicable to Maine Yankee in the permanently shutdown condition.
2.0 BACKGROUND
The NRC may grant exemptions from the requirements of its regulations, which, pursuant to 10 CFR 50.12(a), (1) are authorized by law, will not present an undue risk to public health and safety, and are consistent with the common defense and security and (2) present special circurnstances. Section 50.12(a)(2) of 10 CFR Part 50 identifies some of these special circumstances to be whers application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule, compliance would result in undue hardship or cost that are significantly in excess of those incurred by others similarly situated, and circumstances exist that were not considered when the regulation was adopted for which it would be in the public interest to grant an exemption.
9809140219 980903 PDR ADOCK 05000309 F
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2 In the licensee's submittals, the following special circumstances were presented. Maine Yankee was shut down on December 6,1996, and is now in a permanently shutdown and l
defueled condition. With the plant in a permanently shutdown and defueled condition, the applicable design-basis accidents are limited to a fuel handling incident, spent fuel cask drop, and radioactive liquid waste system leak and failure. The calculated maximum offsite dose from these postulated releases is less than the U.S. Environmental Protection Agency (EPA) Protective Action Guides (PAGs). The licensee also estimated that, by March 1998, a beyond-design-basis event, involving fuel damage (caused by a loss of spent fuel pool water and a subsequent overheating of the stored fuel) and the release of radioactive materials sufficient to exceed EPA PAGs at the site boundary is not credible. Once a radiological release warranting prompt offsite response is no longer possible, offsite response capability, including offsite emergency plans, would no longer be necessary. The licensee stated that requiring Maine Yankee to comply with the requirements for offsite emergency planning when it is no longer warranted would result in undue financial and administrative hardship to Maine Yankee, its owners, and their ratepayers.
Notwithstanding the licensee's position stated above, the staff, as discussed in Sections 3.1.2 and 3.2, identified a very low likelihood bounding accident that could result in an offsite consequence, but that the length of time available provides confidence that offsite protective measures for the public could be taken without the need for preplanning.
Therefore, the requirement that emergency plans meet all of the standards of 10 CFR 50.47(b) and all of the requirements of Appendix E to Part 50 is not now warranted at Maine Yankee.
3.0 DISCUSSION AND STAFF EVALUATION 3.1 Radiolooical Conseauences
. Revision 14 to the Maine Yankee Defueled Safety Analysis Report (DSAR) includes revised analyses of postulated accidents at Maine Yankee in its permanently shutdown status.
Chapter 5 of the DSAR describes the radiological consequences of accidents that could release radioactive materials, as well as the consequences of a spent fuel pool draindown event. The staff reviewed the licensee's analyses, as modified in licensee submittals dated July 9 and August 5,1998, to determine whether the radiological impact of these events would require an offsite emergency plan.
3.1.1 Bgsin Handlina Event Decontamination of systems during decommissioning and dismantlement operations will
- generate significant quantities of radioactive waste in the form of contaminated demineralizer resins. The licensee has postulated a bounding accident for the release of l
radioactivity: the dropping of a highly loaded spent resin liner within the low-level-waste storage building (LLWSB), resulting in the liner failure and a release of a fraction of its radioactive materials in an airborne cloud. The analysis indicates that an individual at the exclusion area boundary (EAB) could receive up to 0.11 rem total effective dose equivalent (TEDE) from this event.
3 The licensee stated that this event was considered to have higher offsite consequences than the mishandling of resin during resin liner filling and dewatering operations since these activities are performed in containment. Holdup and confinement of radioactive materials in a containment that is isolated would significantly decrease the potential for offsite release. In addition, the licensee committed in the DSAR to establish administrative controls to ensure that calculated offsite doses from potential decommissioning accidents do not exceed those calculated for a spent resin cask drop accident.
The licensee did not postulate a fire concurrent with the resin mishandling event due to the low flammability of the resin itself and the absence of flammable materialin the LLWSB.
However, the analysis did assume that 1.0 percent of the radioactivity in the liner became airborne during the event. This assumption is the same fraction of material expected to be released by a fire, and is consistent with the release fractions listed in Schedule C to 10 CFR 30.72 for mixed fission and corrosion products. The calculational methods and assumptions used in this analysis are acceptable to the staff.
3.1.2 Fuel Pool Draindown Although the fuel on site has decayed for a minimum of a year, a significant quantity of radioactive material remains in the spent fuel pool in the form of spent fuel assemblies.
Water and the concrete pool structure provide radiation shielding on the sides of the pool.
However, water alone provides most of the shielding above the spent fuel. A loss of shielding above the fuel could increase the radiation levels at the EAB from the scattering of gamma rays streaming up out of the pool. The licensee postulated a pool draindown event resulting from a break in the pool cooling system piping, concurrent with a failure of the associated anti-syphon device. The licensee assumed that additional pool water was lost through pool boiling for the folluwing 4 days before effective corrective actions could be taken to reestablish adequate pool water level. The licensee calculated that the dose rate would be 0.00076 rem per hour at the EAB. In addition the licensee calculated the postulated offsite dose rates in the event of a complete draindown of the spent fuel pool (a beyond-design-basis event). Assuming only 1 year of radioactive decay and a site boundary distance of 610 meters, the complete draindown resulted in a postulated dose rate of 0.01 rem per hour. The licensee's calculated dose rate indicates it would take 4.1 days for this event to exceed the EPA early-phase PAG of one rem.
By letter dated May 15,1998, the licensee submitted analyses for a complete loss of inventory and several partial loss-of-inventory events within the spent fuel pool. That analysis showed that a partial draindown was more severe than a complete draindown for the licensee's plant. For this case, only 5.5 feet of the active fuel is covered by water.
The licensee calculated that it would take 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> for the cladding to heat up to 827 *C.
However, the staff reviewed the calculations and determined that the bounding scenario would be with the active fuel totally uncovered and water blocking the assembly inlet so.
i that no natural circulation flowpath exists. The staff calculated that, for this case, as of August 1,1998, it would take approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> for the hottest location in the highest power assembly to reach 900 'C. The heatup time was calculated assuming an adiabatic heatup of a fuel rod and using conservative decay heat assumptions. An adiabatic heatup is defined as one in which all heat generated is retained in the system, with no heat loss to the surroundings. This definition corresponds to a physical situation in i
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4 which the spent fuel pool water is lost, no cooling mechanism is available, and the fuel is surrounded by a perfect insulator. The staff considers this scenario bounding for any loss-of-inventory scenario, since any other scenario would have some heat removal from the assembly and a longer heatup time. Consequently, the staff determined that, in view of the low likelihood of the bounding scenario, and the time elapsed since the shutdown of the facility, there would be sufficient time for mitigative actions and, if necessary, offsite protective measures to be initiated after a postulated loss of water and before a postulated release of radioactivity resulting from spent fuel overheating.
3.2 Emergency Plan Exemptions Request in accordance with 550.54(q), a licensee authorized to possess and operate a nuclear power reactor must follow and maintain in effect both onsite and offsite emergency p!ans that meet the standards in 550.47(b) and the requirements in Appendix E to 10 CFR Part
- 50. A licensee may make changes to these plans without Commission approval only if the changes do not decrease the effectiveness of the plan and the plan, as changed, continues to meet the standards of 650.47(b) and the requirements of Appendix E to 10 CFR Part 50.
Proposed changes that decrease the effectiveness of the approved emergency plans may not be implemented without application to and approval by the Commission.
The licensee requested exemption from the following specific requirements:
As required in 650.54(q), the licensee requested NRC approval to eliminate the requirement that the Maine Yankee emergency response plans meet all of the standards of 10 CFR 50.47(b) and all of the requirements of Appendix E to Part 50. The licensee stated that the onsite plans would remain subject to the standards as modified by this requested exemption. In accordance with the provisions of 650.54(q), when a change to an emergency plan is made, the staff evaluates that change against the bases for commitments made in the plan to determine whether there is a decrease in effectiveness.
It is not a decrease in effectiveness if the reduction in the commitment is commensurate with a reduction in the bases for that commitment. In this instance, the staff has determined that there has been a reduction in the bases that require offsite emergency planning. For a bounding accident scenario at#.aine Yankee, as discussed in Section 3.1.2 above, the staff determined that the length of time available provides confidence that mitigative actions and additional offsite measures could be taken without preplanning, if required.
As discussed in Section 3.1.1 above, the licensee committed to establish administrative controls to ensure that calculated offsite doses from potential decommissioning accidents do not exceed those determined for a spent resin cask accident, which are a small fraction of the EPA early-phase PAG (1 rem) to any individuallocated off site.
i Given that the postulated dose to the general public from any reasonably conceivable
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accident would not exceed the EPA PAG and, for the bounding accident, the length of time I
available provides confidence that offsite measures for the public could be taken without preplanning, the emergency plan commitment for offsite emergency planning may be
5 reduced. Therefore, the staff concludes that the requirement that emergency plans meet
- all of the standards of 10 CFR 50.47(b) and all of the requirements of Appendix E to 10 CFR Part 50 is not now warranted at Maine Yankee. The emergency plans would
- remain subject to the standards as modified by requested exemption.
The staff found this change acceptable.
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The licensee requested an exemption in order to eliminate reference to the term
" Emergency Planning Zones" (EPZs) in defining which organizations would be included in the emergency plan. The' emergency plan would continue to address appropriate onsite and offsite response organizations.
l The staff found this change acceptable.
No exemption was requested.
The licensee requested an exemption in order to eliminate from the standard the arrangement to accommodate State and local staff at a near-site emergency operations j
facility. The emergency plan would continue to maintain arrangements for requesting and using assistance resources from other organizations.
i The staff found this change acceptable.
The licensee requested an exemption from the need for State and local plans to rely on information provided by the licensee for offsite response measures.
The staff found this change acceptable.
The licensee requested an exemption from the need for establishing procedures and means for notification of the public within the EPZ.
The staff found this change acceptable.
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-The licensee requested an exemption from the need for the provision of prompt I
communications with the public.
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The staff found this change acceptable.
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~ The licensee requested an exemption from the need for providing information to the public j
"on a periodic basis concerning initial actions in an emergency, and a physical location for the dissemination of information to the news media.
The staff found this change acceptable.
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No exemption was requested..
10 CFR 50.47(b)(9) i The licensee requested an exemption from the requirement to have the capability to assess and monitor specifically "offsite" consequences of radiological emergency conditions.
The licensee's exemption request is based on its conclusion that no design-basis accident or credible beyond-design basis accident can result in radioactive releases that exceed EPA PAGs at the site boundary. The bounding accident assessed by the staff was a low-likelihood event that postulated doses in excess of EPA PAGs. However, the length of time available provides confidence that offsite measures for the public could be taken without preplanning. In Section 7.0, " Assessment of Releases," of the licensee's draft DEP, the licensee commits to the following:
1 "Using the instrumentation available, as described in Section 5.0, the initial response to an event will be to ascertain the cause, mitigate further progression and determine i
the potential impact to station personnel and the general public.
" Initial assessments will consist of verifying the parameters that indicate a release may
' be in progress and initiating a dose assessment based on that information.
j "As soon as practicable, facility staff should initiate general area radiation surveys and airborne sampling to determine the actual extent of a radiological release. Results of the surveys will be analyzed by facility staff to formulate an action plan to mitigate the event and restore the facility to a safe condition. Survey data will also be used, as appropriate, in any dose assessment techniques.
l "Once the TSC is staffed, the Radiological / Hazard Assessment Coordinator assumes responsibility for dose assessment activities. The methodology to be used may consist of computerized dose assessment models, nomographs or hand calculations, j
depending on the severity of the event and the point of release to the atmosphere.
l The primary objective of any of these methods is to determine the maximum dose rate i
l and the distance from the point of release where that dose will be realized. From this i
information, protective actions can be formulated and implemented to minimize the risk to facility staff.
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"Following the termination of the event, environmental surveys (includin0, but not limited to water, soil, vegetation, etc.) may be required to determine the long-term impact of the event."
The information developed from the capability described abeya would be used to determine whether offsite measures for the general public would be appropriate. The staff found this change acceptable, on the basis of the licensee's commitment to maintain capabilities equivalent to those described in Section 7.0 of the draft DEP submitted in Attachment lli to the licensee's letter dated November 6,1997 (Docket No. 50-309, Accession No. 9711130334).
The licensee requested an exemption from the requircment to develop protective actions for the plume exposure and ingestion pathway EPZs.
The staff found this change acceptable.
No exemption was requested.
No exemption was requested.
No exemption was requested.
No exemption was requested.
No exemption was requested.
No exemption was requested.
l 10 CFR 50.47(c)(2) 1 l
The licensee requested an exemption from the requirement to establish plume and ingestion pathway EPZs.
i The staff found this change acceptable.
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The licensee requested an exemption from the requirement to follow and maintain in effect emergency plans that meet all of the standards of 10 CFR 50.47(b) and all of the requirements of Appendix E to 10 CFR Part 50 with regard to offsite emergency planning.
The staff found this change acceptable.
10 CFR 50 Appendix E Ill The licensee requested an exemption in order to eliminate reference to the term
" Emergency Planning Zones" (EPZs).
The staff found this change acceptable.
10 CFR 50 Appendix E IV The licensee requested an exemption from the requirement to provide an analysis of the time required to evacuate and take other protective actions off site.
The staff found this change acceptable.
l 10 CFR 50 Appendix E IV A.1.
The licensee requested an exemption in order to eliminate reference to the term " operating" and refer instead to the " normal plant organization."
The staff found this change acceptable.
10 CFR 50 Appendix E IV A.3.
The licensee requested an exemption from the requirement to describe licensee headquarters personnel who wi!I be sent to the plant site in an emergency.
The staff found this change acceptable.
10 CFR 50 Appendix E IV A.4.
The licensee requested an exemption in order to eliminate the term "offsite" in re!ation to dose projections that will be performed.
l The licensee's exemption request is based on its conclusion that no design-basis accident or credible beyond-design-basis accident can result in radioactive releases that exceed EPA PAGs at the site boundary. The bounding accident assessed by the staff is a low-likelihood event that found postulated doses in excess of EPA PAGs. However, the length of time available provides confidence that offsite measures for the public could be taken without preplanning.
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9 The staff found this change acceptable, on the basis of the licensee's commitment to maintain personnel with responsibilities equivalent to those described in Section 7.0 of the draft DEP submitted in Attachment lli to the licensee's letter dated November 6,1997.
10 CFR 50 Appendix E IV A.5.
The licensee requetted an exemption from the requirement to identify individuals with special qualifications.
The staff found this change acceptable.
10 CFR 50 Appendix E IV A.6.
No exemption was requested.
10 CFR 50 Appendix E IV A.7.
No exemption was requested.
10 CFR 50 Appendix E IV A.8.
The licensee requested an exemption from the requirement to identify State and local officials responsible for protective actions.
The staff found this change acceptable.
10 CFR 50 Appendix E IV B.
The licensee requested an exemption from the requirement to base emergency action levels on offsite monitoring results and consideration of protective measures outside the site boundary.
The staff found this change acceptable.
10 CFR 50 Appendix E IV C.
The licensee requested an exemption from the requirement to base emergency action levels on offsite radiological monitoring information and information from other sensors, such as containment pressure, that are no longer appropriate. The licensee requested to eliminate emergency classification above the Alert level.
The staff found this change acceptable.
f 10 CFR 50 Appendix E IV D.1.
i The licensee requested an exemption from the requirement for administrative and physical means for the prompt notification of the public of protective measures.
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'O The staff found this change acceptable.
l 10 CFR 50 Appendix E IV D.2.
l The licensee requested an exemption from the requirement for yearly dissemination of
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emergency planning information to the public.
The staff found this change acceptable.
.10 CFR 50 Appendix E IV D.3.
The licensee requested an exemption from the requirement to demonstrate that State / local officials have the capability to make public notification promptly, and changed the time for notification of State and local agencies to within 60 minutes after declaring an emergency.
The staff found this change acceptable.
10 CFR 50 Appendix E IV E.8.
The licensee requested an exemption from the requirement to provide for a near site emergency operations facility.
The staff found this change acceptable.
10 CFR 50 Appendix E IV E.9.a.
The licensee requested an exemption in order eliminate the phrase "within the plume exposure pathway EPZ" from the description of communication systems with State and local governments and to change the frequency of test of these communications to quarterly.
The staff found this change acceptable.
10 CFR 50 Appendix E IV E.9.b.
i No exemption was requested.
10 CFR 50 Appendix E IV E.9.c.
The licensee requested an exemption from the requirements to provide communications among the near-site emergency operations facility, the nuclear facility, State and locel emergency operations centers, and field assessment teams.
The staff found this change acceptable.
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l 11 10 CFR 50 Appendix E IV E.9.d.
The licensee requested an exemption from the requirements for provision of
. communications by the licensee from the onsite technical support center and near-site emergency operations facility to the NRC Headquarters and Regional Operations Center.
The licensee will maintain these communications from the control room and will change the frequency of test of such communications to quarterly.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.1. viii.
The licensee requested an exemption in order to delete Headquarters support personnel and local news media persons from the list of categories of emergency personnel who will be provided periodic training.
j The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.
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The licensee requested an exemption in order to eliminate the requirement to test the public notification system as part of emergency preparedness exercises.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.b.
The licensee requested an exemption in order to eliminate the reference to specific emergency response facilities, Technical Support Center, Operations Support Center, an'd the Emergency Operations Facility.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.c.
The licensee requested an exemption from the requirement for a biennial exercise with full participation of offsite authorities.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.d.
The licensee requested an exemption from the requirement for an ingestion pathway exercise.
The staff found this change acceptable.
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_4 12 10 CFR 50 Appendix E IV F.2.e.
The licensee requested an exemption in order to modify the language of this section by replacing the phrase " located within the plume exposure pathway EPZ" with " support services" to modify and clarify the governmental entities who would be permitted to participate in emergency preparedness drills.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.f.
-The licensee requested an exemption in order to eliminate reference to the Federal Emergency Management Agency (FEMA) and State and local participation in remedial exercises.
The staff found this change acceptable.
10 CFR 50 Appendix E IV F.2.g.
No exemption was requested.
10 CFR 50 Appendix E IV F.2.h.
No exemption was requested.
10 CFR 50 Appendix E IV G.
No exemption was requested.
10 CFR 50 Appendix E IV H.
No exemption was requested.
No exemption was requested.
4.0 CONCLUSION
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The staff concludes that the licensee's request for an exemption from certain requirements of 10 CFR 50.54(q),10 CFR 50.47(b) and (c), and Appendix E to 10 CFR Part 50 is acceptable in' view of the greatly reduced offsite radiological consequences associated with the current plant status. The staff finds that the postulated dose to the general public from any reasonably conceivable _ accident would not exceed EPA PAGs and, for the bounding accident, the length of time available provides confidence that offsite protective measures for the public could be taken without preplanning. The staff finds acceptable the licensee's commitment in the DSAR to establish administrative controls to ensure that calculated
'offsite doses from potential decommissioning accidents do not exceed those determined for i
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13 a spent resin cask drop accident. Therefore, the staff conciudes that the requirement that emergency plans meet all of the standards of 10 CFR 50.47(b) and all of th' requirements e
of Appendix E to Part 50 is not now warranted at Maine Yankee and an exemption from the requirements for offsite emergency planning is acceptable.
The licensee's onsite emergency plan would remain subject to the standards as modified by the requested exemption. The staff has determined that, with the approval of the exemptions from the requirements of 10 CFR 50.54(q),10 CFR 50.47(b) and (c), and Appendix E to Part 50 for emergency planning, as detailed above, the licensee may revise its emergency plan consistent with the remaining requirements.
Principal Contributors:
Daniel M. Barss Roger L. Pedersen Diane T. Jackson Joseph L. Staudenmeier Date: September 3, 1998 t
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