ML19323D965
| ML19323D965 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/20/1980 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8005220597 | |
| Download: ML19323D965 (6) | |
Text
BALT!MORE GAS AND ELECTRIC COMP / NY P. O. D O X 1475 B A LTI M O R E. M ARY L AN D 21203
!May 20, 1980 AnTHUR E LUN DVA LL.Jn.
v.c s swr sir.r '
'A Vvst Crrice of !!uclear Beactor Regulation U.
M.
!:uelear Reculatory Conninnion Vanhinrton, D. C.
20555 Attn:
!!r. Robert A. Clark, Chief Operatinc Heantorn Branch //3 Division of Licencing Cubject:
Calvert Cliffs I uclear Power Plant Units IIon.1 & 2, Dockets I!os. 50-31'T & 50-318
_ LNG Contingency Plan
Reference:
!!RC letter dated 3/31/60 fron R. U. Reid to A. E. Lundvall, Jr., same subject.
Gentlenen:
The r( ferenced letter, which van cent to un an a follovup to meetincn held on February 21. 1980 and February 27, 1980, requented un to nrovide specific information concerninr: the content and bSnin for cur I.';G Continrency Plan. The attachnent to this letter containn the IIRC'n nuentionn and our rennonnec. !4ont of the rennonnen refer to our reviced L:!G Contincency Plan, which in ncheduled to be subnitted to !!RC nn a part of the overall Site Energency Plan in mid-June. We vill, as aereed, urovide you with a draf t gony of the LI!G Plan as soon as it's typed.
Very truly yours,
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r** e f~m s u. nag W.C O.r.~'~'~a r
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J. A. Biddison, Esquire G. F. Trowbridge, Esquire l'.r. E. L. Conner, Jr.
8005220549 p
/DDITTONAL INFOP"ATION CALVERT CLIFFS LNG CONTINGENCY PLAN 1.
Discuss your continuing ef forts in the area of LNG vapor cloud
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detection technolory.
We vill, on a continuing basic anproximately every two years, conduct a survey of apn}icable sources to determine if a reliabic early varning detection system is available at a reasonable cost which could be installed at Calvert Cliffs to detect methane clouds or LNG pools on the Bay.
T f.
Describe your experience with the monitoring of broadcast connunication linha with the Coast Guard. Discuss the status of, progress of letters of agreement between the Coast Guard and Cove Point with respect to notifying the plant of any difficulty with LUG spills / handling.
We have determined, nursuant to nany discussions with NRC, that the most acceptable means of nonitoring broadcast conmunications concerning LUG is to be totally passive and not rely on any other agency to specifically notify us of LNG energencies. Uc will monitor LNG control frequencies passively with our scanner located in the Control Room, and Jur LUG cmergency broadcast tone vill be immediately detected, and our Control Room vatchstanders vill take appropriate action in accordance with our revised LUG Contingency Plan,Section II.
3.
a.
Discuss your protective procedures assuming that an LUG spill
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vith an ensuing fire exists.
b.
Discuss your prote'etive procedures assuming that an LNG cpill with ensuing liquid pool spread and LUG vapor generation occurs.
The revised LUG Contingency Plan, which will be submitted as a part of the revised Site Pmergency Plan in mid-June 1980, discusses the protective procedures for' LUG spills.
Spills with ignition at or near the snill site are not expected to impact on Calvert Cliffs since such spill-site fires vill be,by definition,on the Bay surface some distance from Calvert Cliffs.
Fires which occur at the Calvert Cliffs site are not expected to cause any cinnificant heat load damage to plant structures as discussed in our initial LUG hazards investigation report, " Report on Investigations and Literature Survey to Establish the Hazard Implications of LUG Spills at the Columbia LNG Corporation Receiving Terminal at Cove Point, MD, on the Calvert Cliffs Uuelear Power Plant", Wesson and Associates, Inc., March 12, 1976.
Spills which result in an unignited methane cloud are also addressed in the revised Contingency Plan.
0
l
. h.
Assume an LNG vapor cloud on 5ite.
Provide estimates of the duration of the plant's innersion in the a.
cloud, and correlate those estinates with the proposed emergency
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actions.
If an LNG pool forts on the surface of the Bay with a vind blowing from the pool to Calvert Cliffs, the vorst case assumption is that the methane can cloud begins its travel toward Calvert Cliffs inmediately upon evaporation initiation, and the length of the cloud is equal to the vind speed tines the tine it takes to evaporate the entire pool.
Assuming the methane cloud noves at the speed of the wind, then, the residence tine of the methane cloud over the plant cannot be any longer than the time it takes for the entire pool to evaporate.
Please exanine the following relationships.
Distance from pool site to plant = X mi Vind speed = V nnh Time of start of evaporation = t1 Time of completion of evaporation = t2 Time to evaporate pool = t2-t1 = At Time of first methane molecule reaching Calvert Cliffs = t3 (t3 - t ) hours = (x miles) + (V "il"3 )
then:
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and the time of last methane molecule reaching Calvert Cliffs = th th = t2 + (X niles) : (V milen-)
hour so:
residence time = th - t3 nnd: t3 = X/V + ti and: th u tj+X/V so:
th - t3 = t'2 + X/V - X/V - ti or:
th - t3=t2-ti vhere: t2 - tl = tine to evanorate pool Therefore :
Residence Time = Evaporation Time Numerous studies done by Science Applications, Inc. have shown that the evaporation time for a 2h,000 - 35,000 cu. neter spill on unconfined water is about 10-15 minutes.
Using this range as an estimate of residence time, ve can apply a factor of 2 to make the residence time
= 30 minutes.
Hence ve can estimate that the plant could be "imnersed" in flammable methane for up to 30 minutes. This is a very conservative estimate since:
. (1) It assumes the entire sn'ill volume of LNG becomes > 5% nethane which all reaches Cnivert Cliffs undinsivated.
(2)
'de have included a " safety factor" of 2.
The revised Contingency plan providen operator guidance for determining actions to be taken based on entinates of the time it will take for the cloud to reach the plant. Assuming a spill 5 miles away with a 5 mph vind, the cloud vill arrive in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and reside for 30 minuten.
Thus, if the station batteries were fully loaded at the 2-hour rate, there would ntill be 30 ninutes of battery capacity remaining after the
" conservative" cloud han fully dissipated and/or passed over the plant.
Thin in nufficient time to either start the emergency diesel generators or bring the 69 hV line on service.
h.
b.
Dincuns the basin and nrovide quantifiabic decision criterin for inhibiting the dicael generators from starting.
The banes for inhibiting the diesels are discunned "in the revised Contingency Plan. In general, they can be sumnarized an follows:
Any sizj snill which occurs closer than sone designated initial distance from tre plant vill direct the plant operators to standby to inhibit the dicnels.
Likewise, a spill of any potential size greater than a riven noccified sine at any dintance from the plant vill direct the operators to stand by to inhibit the diesels. Thene criteria are in graphic forn in the revised Continnency Plan.
The final decision to inhibit is bnned on an actual onsite methane concentration reading obtained by a portable detector hand-held at the intake structure.
h.
c.
Discuss the 3etection and menna of purging the diesel rooms of vaporized LUG after the cloud disperses.
The diesel generator rbons are located on the landvard side of the Auxilinry Building facing inland.
The Auxiliary Building, both containments, and the Turbine Building all must be passed before a nethane cloud can reach the diesel rooms. Additionally, the diesel room air intake louvers are located at approximately 50 feet or more above sea level. When th'e dienels are prevented from starting, there vill be no forced suction of outside air (or nethane) into the rooms.
Natural convective and gravitational forces are the only neans of possibly getting methane into the roons.
Even then, it must pasn through the louvers.
In the very unlikely event that the Calvert Cliffs Diesel Generator Rooms become full of 55 methane gas, ve vould simply open the doors and test for methane with a portable detector.
If finnmable concentrations exint, a portable air blower vill be used to exhaust the roons.
The blower motor vill be outside the rooms with a hone taking suction in the rooms and exhausting to' atmosphere. All motors, etc. incide the rooms vill be " sniffed" for methane.
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h-k.
d.
Discuss means of nrotection of the battery and charger roons from LNG vapor hazards.
The battery rooms are cerved by a cloced ventilation system.
If a battery charge is in Drogrenn, it vill be secured an specified in the reviced Plan and hydrocen buildun vill be nonitored if the ventilation systen is secured.
The chargers vill not be charging the batterien if methane incursion in possible.
h.
e.
Dineusn the criteria and procedures related to alternate power sources after the batterica are exhaunted (including cynteu/ component sequencing).
As discussed in h.a. ve do not expect the batteries to be exhaunted under the vornt conditions. However, the reviced Contingency Plan has provisions to align the 69 kV (SMECO) line for emergency power uce vell in advance of methane incursion to the site.
The 69 kV line can cerve all normal nafe chutdown equipment for toth units indefinitely.
Seouencing, if necensary, vill be none in accordanc'c with existing plant procedures.
h.
f.
Explain the rennon for the two hour duration availability of the D.C. (battery) power sunnly, and state why this in considered to be adequtte.
Please refer to our response to h.n.
h.
c.
Dincuss the innnet on the svitchyard of detonation /derlagration of the LUG cloud.
Prior to methane arrival onsite, the plant vill be divorced fron offsite power.
Damage resulting to the switchyard from a nethane burn vill not imnact the naintenance of safe shutdown conditions.
Specifically:
a) The batteries can be used fully loaded for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> until:
b) The 69 kV line pic's up the station loads or:
c) The diesel generatorn can be brought on line.
The 69 kV line is virtually all underground on the site and is thus, effectively immune to a methane burn, h.
h.
Discuss the need for and availability of alternative access vays to the site if a cloud detonation / deflagration were to occur.
Normal site access is from Route h, which is inland from the plant.
The treeline setback from the access road in adequate to permit vehicle necess even if the surrounding voods caught fire. Additionally, nuch of the access road passes through unvooded areas which vould serve to break the fires that night develop. There are numerous available helicopter landing sites available, and seavard approaches vill be available after burn / passage of the methane cloud.
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5.
Discuss the various options f'or ntorar.c and assembly locations for breathing apparatus and nethane detection annaratus.
State the number
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of peonle to be processed, the number of airnacks on hand, the time required to implement use of the airpacks, and the modes of use of the sniffing apparatus.
Dmergency equipment storage location and use is discussed in the revised Contingency Plan.
- j. Uhen addressinc specific protective actions, reference the plant procedures necessary to implement such action, and the approuriate review, evaluation, and implenentatien of such plant procedures.
All required procedures are specifically called out in the aupropriate sections of the Emergency Plan and/or Contingency Plan.
Procedure reviev, evaluation and innlementation are conducted in accordance with approved plant procedures.
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