ML20205D401

Responds to Sent to Lj Callan Re Emergency Preparedness & Financial Protection Exemption Requests Made by Util & Requests Meeting Scheduled at NRC Headquarters Be Rescheduled & Held in Vicinity of Myaps

ML20205D401
Person / Time
Site:	Maine Yankee
Issue date:	03/26/1999
From:	Weiss S NRC (Affiliation Not Assigned)
To:	Shadis R AFFILIATION NOT ASSIGNED
References
NUDOCS 9904020185
Download: ML20205D401 (7)

Text

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, pocrog ju & UNITED STATES U E NUCLEAR REGULATORY COMMISSION E " WASHINGTON, D.C. 20555-0001 k....[E March 26, 1999

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1 Mr. Raymond Shadas j F,iends of the Coast P.O. Box 98 Edgecomb, ME 04556  ;

Dear Mr. Shadis:

I am responding to your letter of June 5,1998, that you sent to Leonard J. Callan of the U.S. Nuclear Regulatory Commission (NRC) regarding emergency preparedness ana financial protection exemotion requests made by Maine Yankee Atomic Power Company (MYAPC) for the Maine Yankee Atomic Power Station (MYAPS), in your letter, you requested that (1) a meeting scheduled at NRC Headquarters be rescheduled and held in the vicinity of MYAPS, (2) NRC clarify its safety concerns regarding the MYAPS spent fuel pool, and (3) NRC not act on MYAPC's exemption applications until certain design ,

features and accident scenarios were analyzed with respect to current and proposed spent fuel pool operating conditions. The NRC has already discussed these issues at meetings and phone conversations between you and Mike Webb, the MYAPS Project Manager. )

This letter serves to document the results of all the NRC interactions with you on these I issues.

The NRC determined that the meeting between members of NRC and the MYAPC staff should be held on June 9,1998,~at NRC Headquarters as scheduled. Although the NRC is sympathetic to your concern that interested citizens cannot always arrange their work schedules and obtain reasonably priced airfares on short notice to observe such meetings at NRC Headquarters, we believe that appropriate notice had been provided to the public in accordance with the NRC Final Policy Statement on Staff Meetings Open to the Public, in addition, we noted that it would be prohibitively difficult (and expensive) to rearrange the schedules and Wrango for travel for the 'large number of NRC staff (14) who attended the meeting, in the future, the NRC will try to hold meetings, when possible, in the vicinity of the plant. The NRC staff did, in fact, meet on November 9,1998, at the site f with MYAPC and its decommissioning operations contractor, Stone & Webster Engineering O Corporation, in a meeting open to the public and observed by several members of the local community, to discuss future site activities and the schedule for decommissioning. I' WTUj With respect to your questions regarding NRC's safety concerns about the spent fuel pool, the NRC staff has determined that a scenario that should be addressed for a permanently shutdown reactor involves the loss of all or nearly all of the water from the spent fuel pool and subsequent heatup of the fuel. If the decay heat is high enough, oxidation of the zirconium fuel clad could become self-sustaining, resulting in a 'irconium clad fire.

Although the zirconium clad fire may not be included in the design basis of the facility (as MYAPC has noted), the NRC staff considers it among those events that are " reasonably i conceivable" and that should be considered in determining that there is no undue risk to the public from a permanently shutdown reactor facility. While the consequences of this scenario are not considered by the NRC to be worse than previously estimated, the staff 9904020195 990326 -

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Mr. Raymond Shadis evaluates this scenario more closely because it is no longer bounded by events that could

-occur at an operating plant. The evaluation is based on the length of time after shutdown, which is unique for each plant, when the decay heat is insufficient to cause a fire and the scenario is no longer possible. In the interest of the most effective use of the NRC and MYAPC resources, the staff postulated a bounding theoretical case (an adiabatic heatup of the fuel in which all heat generated in the fuel is retained in the system with no

' heat loss to the surroundings). For this bounding scenario, the time available to reach the self-sustaining oxidation temperature (approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> on August 1,1998),'

provided sufficient time for onsite actions, and, if necessary, offsite protective measures to be initiated before a postulated release of radioactivity resulting from spent fuel overheating. Based on plant information and analysis, the NRC determined for MYAPS that in the event of the unlikely case of a loss of all spent fuel pool water, sufficient time had elapsed since final shutdown to warrant granting the emergency preparedness exemption in early September 1998.

You also requested that the NRC not take action on the MYAPS emergency plan and l financial protection exemption requests until certain design features and accident scenarios are analyzed. To evaluate the level of offsite en.vgency preparedness needed at a permanently shutdown facility, the NRC staff evaluates tnose accidents or scenarios that would result in offsite consequences. For permanently shutdown plants, the staff has determined that the worst radiological consequences would result from a loss of all or nearly all of the water from the spent fuel pool. The staff believes that although it is unlikely to occur, for some period after permanently ceasing operations, the loss of water from the spent fuel pool is the worst credible scenario for the decommissioned piant. In l

your letter, you asked several questions regarding the plant design and different scenarios that we have determined are included in or bounded by the identified worst case scenario.

Since your issues fell within the these bounds, and therefore would have lesser consequences than the worst case scenario, we have not addressed each of your

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questions individually. Although we have not addressed each question indlvidually, we '

have tried to address your concerns collectively.

You expressed concern about the construction of the spont fuel pool and the pool cooling ,

1-system. The staff reviewed th'e design information of the MYAPS spent fuel pool, and I specifically your concern that the upper portion of one spent fuel pool wall is next to the  !

i primary auxiliary building. In its review, the staff noted that all the walls (including the wall shared with the primary auxiliary building) of the spent fuel pool are 6 feet thick and constructed of reinforced concrete. The poolis seismically qualified; that is, it will remain functional after the hypothetical earthquake determined for that plant area. The hypothetical earthquake is larger than any earthquake actually experienced in that area. I The MYAPS spent fuel poolis also founded on bedrock. In fact,it is also embedded j 12.5 feet in the ground. The normal spent fuel pool cooling system is not required to be i

seismically qualified; therefore, NRC does not require the backup generators for the spent j fuel pool cooling system to be seismically qualified either. Additionally, the structure over the spent fuel pool is designed to withstand a hypothetical earthquake and tornado winds.

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Mr. Raymond Shadis You also raised concerns about the south wall of the spent fuel pool building. Through l exaaustive review of MYAPS'. Individual Plant Examination, we could not identify where I they were asked to analyze the effects of the collapse of the south wall. However, as j part of an open issue identified by the NRC staff concerning NRC Inspection and {

Enforcement Bulletin 80-11, " Masonry Wall Design," MYAPC provided a consequence I analysis for failure of the spent fuel pool masonry wall. By letter dated December 10, 1987, the NRC staff informed MYAPC that it had determined that, in the event of a masonry wall failure, adequate spent fuel pool cooling capability is available and the structuralintegrity of the racks is adequate. The determination was based on an NRC staff Supplemental Safety Evaluation and a Technical Evaluation Report prepared by the Franklin Research Center under contract to the NRC. The staff does not intend to reanalyze this event.

l You also were concerned about the freezing event that occurred in 1994 at the Dresden l Nuclear Power Station, Unit 1 (Dresden 1), in that incident, several thousand gallons of service water (not spent fuel pool water as you stated) were deposited in the empty containment sphere when a valve in the service water system froze and ruptured.

Althcugh no spent fuel pool water was lost, because the spent fuel pool at Dresden 1 is i l connected to the containment through the fuel transfer tube, the NRC was concerned that the fuel transfer tube was also vulnerable to freezing and possible failure. To isolate the enclosure from the spent fuel pool water, a blind flange was weldec to the fuel transfer tube. At Maine Yankee, draindown of the pool to the containment through the fuel transfer tube is prevented by two independent mechanical devices, an isolation valve l located in the spent fuel pool and a blind flange seal at the refueling canal in the containment. The staff believes that these means of isolation coupled with the licensee's cold weather operations procedures provide adequate assurance that protracted 'ow l temperatures will not result in freeze damage that would have significant radiological I consequence.

1 You also discussed the issue of aircraft accidents involving the SFP and asked what actions the NRC has undertaken to address concerns raised at the November 7,1997, PSDAR meeting and if the NRC will require and verify analysis of potential aircraft accidents involving the Maine Yankee SFP. While the plant was still operating, an evaluation of the aircraft hazard at Maine Yankee was performed to determine if the  ;

facility met criteria specified in the NRC's Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants (NUREG-0800) (SRP). As per the SRP, Maine

. Yankee was considered adequately designed against aircraft hazards. The P-3 Orion aircraft that operate from Brunswick Naval Air Station are variants of the same aircraft ,

that were flown at the time of the plant's initial .icensing and, therefore, do not constitute a different hazard than previously assessed. Therefore, the staff does not intend to require Maine Yankee to submit an additional airuaft accident analysis regarding the SFP.

You expressed concem about a new trailer-mounted generator outside the spent fuel building being a potential tornado missile. Tornado missiles that are of concern in the decommissioned state are missiles that can damage the spent fuel pool structure such that its watertight integrity would be damaged or are missiles that would have a trajectory that will contact the fuel when fuelis in the spent fuel pool MYAPC's analysis included a

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, Mr. Rsymond Shadis March 26, 1999 1,850-pound utility pole, which is 35 feet long and 14 inches in diameter, traveling at f 150 mph, and a 1-ton automobile traveling at 150 mph. This licensing basis is still applicable in the decommissioned state. The wood blocks under the trailer that you

discussed in your letter are'similar to the telephone pole hazard and do not need further

! review. Regarding the generator and the trailer, the NRC staff asked the licensee for further information. On the basis of the information provided, we determined that the j generator and the trailer weigh more than 15 times the missiles that were ' analyzed.

l Although not quantified, this large weight lea'ds us to believe that there is a low likelihood '

l that the trailer would be picked.up by a tornado, moved in the direction of the spent fuel l pool, and deposited therein.' Because it is much larger than the objects that we believe should be postulated as tornado missiles and because of the low likelihood of the j sequence of events that would have to occur in order for the generator and the trailer to j damage the spent fuel, we do not believe that the generator and the trailer would become i a tornado-generated missile that would damage the fuel.-

You asked many questions regarding unanalyzed conditions and draindown rates, flow rates, and volu;nes of water drained from the spent fuel pool. There is a nearly unlimited number of different conditions, including drain down and flow rates, that could be postulated. However, as previously discussed, the NRC staff does not analyze every condition or scenario for a plant; rather, we evaluate scenarios or accidents that are believed to be bounding, that is, would have the most severe offsite consequences, to be analyzed and planned for through emergency planning. Thus, we do not require licensees to analyze how much water would drain out of the pool at different break locations; instead they analyze the pool to a completely or nearly completely drained level without regard as to whether the water actually has sufficient space to drain. Although this scenario may not be credible it certainly is bounding and conservative in evaluating offsite consequences. If it can be shown that the consequences of this scenario do not require sheltering or evacuation, and therefore, no offsite emergency plan, or that time is available j to take mitigative actions to adequately protect public health and safety, the NRC will  ;

allow the licensee to eliminate the offsite portion of its emergency plan. In Maine  !

Yankee's case, the staff performed its analyses and was able to determine that sufficient time had elapsed since final shutdown to warrant granting the emerce y planning exemption in early September 1998. j We appreciate you sharing your concerns on the decommissioning process at MYAPS with us, if you have any further questions, please contact Mike Webb at 301-415-1347. i Sincerely, I ORIGINAL SIGNED BY:

Seymour H. Weiss, Director Non-Power Reactors and Decommissioning Project Directorate Division of Regulatory improvement Programs Office of Nuclesr Reactor Regulation Docket No. 50-309 cc: See next page DISTRIBUTION: See next page

• PREVIOUSLY CONCURRED 1

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Mr. Raymond Shadis l 1,850-pound utility pole, which is 35 feet long and 14 inches in diameter, Paveling at I

150 mph, and a 1-ton automobile traveling at 150 mph. This licensing basis is still applicable in the decommissioned state. The wood blocks under the trailer that you 1 discussed in your letter are similar to the telephone pole hazard and Jo not need further review. Regarding the generator and the trailer, the NRC staff asked the licensee for further information. On the basis of the information provided, we determined that the f generator and the trailer weigh more than 15 times the missiles that were analyzed. )

Although not quantified, this large weight leads us to believe that there is a low likelihood l that the trailer would be picked up by a tornado, moved in the direction of the spent fuel pool, and deposited therein. Because it is much larger than the objects that we believe g should be postulated as tornado missiles and because of the low likelihood of the 1 sequence of events that would have to occur in order for the generator and the trailer to damage the spent fuel, we do not believe that the generator and the trailer would become a tornado-generated missile that would damrage the fuel. j You asked many questions regarding unanalf zed conditions and draindown rates, flow l rates, and volumes of water drained from the spent fuel pool. There is a nearly unlimited  !

number of different conditions, including drain down and flow raros, that could be postulated. However, as previously discussed, the NRC staff does not analyze every condition or scenario for a plant; rather, we evaluate sce:iarios or accidents that are believed to be bounding, that is, would have the most severe off' site consequences, to be analyzed and planned for through emergency planning. Thus, we do not require licensees to analyze how much water would drain out of the pool at different break locations; instead they analyze the pool to a completely or nearly completely drained level without ,

regard as to whether the water actually has sufficient space to drain. Although this I scenario may not be credible it certainly is b%nding and conservative in evaluating offsite consequences. If it can be shown that ine consequences of this scenario do not require sheltering or evacuatio,, and therefore, no offsite emergency plan, or that time is available to take mitigative actions to adequately protect public health and safety, the NRC will allow the licensee to eliminate the offsite portion of its emergency plan. In Maine Yankee's case, the staff performed its analyses and was able to determine that sufficir it time had elapsed since final shutdown to warrant granting the emergency planning exemption in early September 1998.

We appreciate you sharing your concerns on the decommissioning process at MYAPS with I us. If you have any further questions, please contact Mike Webb at 301-415-1347.

Sincerely,

' l QAA4 l Seymour H. Weiss, Director Non-Power Reactors and Decommissioning l Project Directorate Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation Docket No. 50-309 cc: See next page l

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! -l Maine Yankee Atomic Power Company Docket No. 50-309 l cc:

Mr. Charles B. Brinkman Friends of the Coast Manager - Washington Nuclear f

P.O. Box 98 i Operations Edgecomb, ME 04556 ABB Combustion Engineering 1 12300 Twinbrook Parkway, Suite 330 Mr. William O' Dell I Rockville, MD 20852 Operations Director f Maine Yankee Atomic Power Company i Thomas G. Dignan, Jr., Esquire 321 Old Ferry Road i Ropes & Gray Wiscasset, ME 04578-4922 I One International Place  !

Boston, MA 02110-2624 Mr. George Zinke, Director Nuclear Safety and Regulatory Affairs Mr. Uldis Vanags Maine Yankee Atornic Power Company

^ State Nuclear Safety Advisor 321 Old Ferry Road State Planning Office Wiscasset, ME 04578 4922 State House Station #38 Augusta, ME 04333 Mr. Jonathan M. Block Attorney at Law Mr. P. L. Anderson, Project Manager P.O. Box 566 Yankee Atomic Electric Company Putney, VT 05346-0566 580 Main Street Bolton, MA 01740-1398 Mr. Michael J. Meisner, President Main Yankee Atomic Power Company Regional Administrator, Region i 321 Old Fenry Road U.S. Nuclear Regulatory Commission Wiscasset, ME 04578-4922 475 Allendale Road King of Prussia, PA 19406 Mr. Robert Fraser, Director Engineering First Selectman of Wiscasset Maine Yankee Atomic Power Company Municipal Building 321 Old Ferry Road U.S. Route 1 Wiscasset, ME 04578-4922 Wiscasset, ME 04578 Mr. Patrick J. Dostie Mr. Mark Roberts State of Maine Nuclear Safety U.S. Nuclear Regulatory Commission Inspector 475 Allendale Road Maine Yankee Atomic Power Company King of Prussia, PA 19406 321 Old Ferry Road Wiscasset, ME 04578-4922 Mary Ann Lynch, Esquire Maine Yankee Atomic Power Company Mr. Mark Ferri, Vice President 321 Old Ferry Road Decommissioning Director

, Wiscasset, ME 04578-4922 Maine Yankee Atomic po ower Company

! 321 Old Ferry Road Mr. Neil Sheehan Wiscasset, ME 04578-4922 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406

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