ML19305B758
| ML19305B758 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 11/08/1976 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19305B745 | List: |
| References | |
| NUDOCS 8003200258 | |
| Download: ML19305B758 (5) | |
Text
.
s W
.,p f,g n,.--..-_3 p
- ::::""~'
[T:.;].,)
m'a Ous.y u u
l l6 L ' ; "
s.n.,. on,e..: :nn w.. u4en.e.a 4..aw. s.cuoa. usem.a 4e:xn Ar.. coa. si7 788-o sso s
L Nove=ber 8, 1976 Director of Nuclear Reactor Regulation O
US Nuclear Regulatory Co==ission D [J r!
Washington, DC 20555 1
b l]
o Il ua DOCKET 50-155, LICE'tSE DPR SIG ROCK POINT PLAUT On July 1, 197h Consu=ers Power Cc=pany submitted an analysis of the Postulated Cask Drop Accident and proposed design and procedural =odificaticns appropriate to reduce the probability of occurrence and the consequences of a postulated cask drop at the Big Rock Point Plant.
By letter dated February 6, 1976, Mr Karl R Galler infor=ed Consumers Power Company that the URC had concluded that the proposed =cdificatiens and procedure changes vould adequately =in":e Q
the probability and potential consequences of a cash drop accident.
In addi-(
tion, he agreed that i=ple=entation o'f equipment modifications within one year of the date of NRC approval was acceptable.
Since the ti=e of :ir Goller's ap-proval, engineering and procure =ent efforts have been initiated such that the modifications could be ec=pleted in a ti=ely =anner. As a result of these engineering efforts, we have concluded that completion of the equipment mod-ifications at this time are both undesirable and unnecessary.
The purpose of this letter is to provide the basis for this conclusion and to describe our present course of action.
The reappraisal of the cask drop equipment modifications has resulted frc= cost estimates being significantly higher than were anticipated when the analysis was sub=itted in July 19Th. The original estimate for =odifications was approxi-mately $100,000.
As of Septe=ber 1976 these esti=ates had escalated to approx-i=ately $1,500,000.
With other potentially large backfitting expenditure ite=s on the horizon, such as Brown's Ferry Fire and industrial security, and because l
the =odifications were pri=arily dictated by the use of the spent fuel shipping cask which vill not be used for at least several years, we feel it is desirable to defer any of these expenses that will not have an i= pact on public health and safety, i
The deferral of portions of this project vill allev a more thorough and orderly evaluation of the cost elements.
Further, it =ay result in greater efficiency of engineering and construction effort by allowing it to be co=bined with other
=cdifications that =ay be required in the future.
j 1
tiO O32 00M3
2
(]
The analysis submitted July 1, 197h considered the co-ten spent fuel shipping cask, the 24-ton spent fuel transfer cask, the 15-ten ecbalt shipping cask, and the T-ton Treat cask. The results and proposed equipment =0difications were largely controlled by the 60-ten spent fuel shipping cask.
Since July of 1974, it has bec =e apparent that we vill not be shipping spent fuel off site for at least several years from the present date.
Thus, for the near-term as the spent fuel shipping cask will not be handled in the plant, there is no need to =ake =odifications which are dictated by consideration of the effects of a postulated drop of this cask.
The drop of the 2h-ton spent fuel transfer cask vas evaluated in A=end=ent 10 to the ESR dated May 3,1962.
During initial design and installatien of the cask and its handling facilities, the cask was provided with safety slings to reduce the probability of a cask drop.
These safety slings are still utilized during all handling of the 2h-ten cask.
The use of this cask with its safety slings was also discussed in the July 1, 197h analysis and in supple = ental infor=ation sub=itted January 22, 1976. Analysis of the postulated drop of this cask shows the consequences to be acceptable.
The July 1,197h analysis shoved that the drop of either the 15-ton cobalt
~
transfer cask or the 7-ton Treat cask might cause da-age to core spray syste=
equip =ent if the cask were dropped in the equipment Icek area.
The analysis did not specifically consider the drop of either cask in the spent fuel pool.
At present we are analyzing the drop of these casks in the spent fuel pool and (qJ looking for different routes in the vicinity of the equip =ent icek area which,
(-
if either of these casks were dropped, vould not result in da-age to vital plant equip =ent.'
If the analysis shows that da= age to the spent fuel pool vould be excessive for the postulated drop of either of these casks, we vill appropriately modify the cask setdown area in the spent fuel pool by installa-tionofalead-spreadingdevice.{Ifanacceptableroutingcannetbeachieved in the equip =ent lock area or if simple modifications cannot be =ade to reduce the consequences of the drop of either of these casks these casks will only be handled with the plant in a cold shutdown condition.
Based on the feregoing, we have concluded that the following modifications need not be perforced until prior to the time the 60-ten spent fuel shipping cask vill again be handled in the plant:
1.
Modification of the crane as described in Section 9.1.1 of the July 1,197h analysis.
2.
Installation of the energy-absorbing =aterial as described in Sectica 9.2 of the July 1, 1974 analysis.
In su==a y, these conclusions are based on the considerations that the 60-ten spent fuel shipping cask vill not be utilized in the near future, that the use of the 2h-ton spent fuel transfer cask was evaluated in the ESR, as a= ended, and that other =easures vill be taken as described abcve to preclude damage to safety-related equip =ent in the unlikely event of either the drop of f
either the Treat or cobalt shipping casks.
I h
0, W lffDP rr/P p D
M O O6] h
] T. k
r3 "O
Modifications to the ventilation syste= vill be ec=pleted as required by Mr Go11er's Februa f 6, 1976 letter or refueling vill not take place unless the centair_=ent ventilatica syste= is isolated.
The procedural =odifications described in the July 1, 197h analysis and sub-sequent correspondence have been i=plemented.
The =cdifications related to the Treat and cobalt casks described in this letter vill be i=ple=ented prior to use of any of the casks following February 6, 1977 and in the case of the ventilation syste=, prior to fuel handling during the refueling cutage which is presently scheduled to ec==ence June 1977 Ralph 3 Sevell (S1 :ed) 6 Ralph 3 Sewell Nuclear Licensing Ad=inistrator CC:
JGKeppler, USNRC y.
D m
D 6
A un h
O e
s l
~_.m.
m.
. _ _ _ _ _ __ -. ~ -.
0 -
l
1
=
Furl Damage Whilm. R: fueling - Ele 3.4, Rev 3 12/9/77 EMP 3.4 FUEL HA'!DLING ACCIDENTS This procedure is not intended for extended use during recovery or restoration following extensive damage incidents where special equip-ment and procedures will be required.
A fuel handling accident may consist of the following incidents:
a.
A rapid insertion or drop of fuel into the core, b.
Transfer cask drop into the core (with fuel in core),
c.
Loss of coolant from the transfer cask during fuel transfer, d.
Fuel drop into the pool, e.
Fuel sipping error.
EFT 3.4.1 SYMPTOMS a.
Fuel handling cable breaks.
b.
Rapid increase of neutron monitors.
c.
Rapid increase of area monitor readings.
d.
Area monitor alar =s.
e.
Neutron monitor alarms.
f.
Reactor scram annunciators, g.
Transfer cask red low-level light is on.
l EMP 3.4.2 AUTOMATIC ACTIONS a.
Reactor safety system may trip if incident occurs over the reactor vessel.
b.
The containment ventilation system will be isolated automatically in the event of an area monitor high radiation alarm from either of the reactor deck area monitors.
EMP 3.4.3 IMBEDIATE OPERATOR ACTION EMP 3.4.3.1.
For rapid fuel insertion into reactor core:
a.
All personnel immediately vacate the sphere, b.
Initiate a reactor scram.
EMP 3.4.3.2 For transfer cask drop into core:
All personnel immediately vacate the sphere.
a.
b.
Initiate reactor scram, c.
Inject liquid poison.
Ehe 3.4.3. 3 For loss of coolant during fuel transfer:
a.
Connect hose from demin water line to transfer cask and supply water to maintain coolant level in cask.
(W '\\} [d l A
D,o m'lD, M - gjgL
2 Fuel Dange '# nile Refueling -- Ee 3.4, Rev 3 12/9/77 DIP 3.4.3.4 For fuel bundle drop into fuel pool. All persennel 1:=nediately vacate the sphere. a. b. Close ventilation valves. DIP 3.h. 3 5 For fuel sipping error: , a. Flood sipper can with water. b. All personnel vacate the sphere. c. Close ventilation valves. DIP 3.4.4 SUBSEQUENT OPERATOR ACTIOilS EF 3.4.h.1 For fuel in'sertion into core: a. Initiate Site Energency Plan. b. Check reactor scran:=ed. c. Check ventilation valves closed. d. Maintain reactor water level at top of over-flow pipes, Monitor radiation levels in sphere. e. E6 3.h.h.2 For transfer cask drop into core: a. Initiate Site Energency Plan. b. ' Check reactor scrammed. c. Check ventilation valves closed. d. Maintain reactor water level below top of overflow p:.yes. e. Monitor radiation levels in sphere. f. Remove clean-up systen from service. BIP 3.h.h.3 For loss of coolant during fuel transfer: a. When power is restored, cove cask to pool j and replace bundle in the storage rack. Et@ 3.h.h.h For fuel drop into fuel pool: a.' Check ventilation valves closed. b. Monitor radiation levels in sphere. D2 3.h.h.5 For fuel sipping error: a. Check ventilation valves closed. b. Monitor radiation levels in sphere.
- (
f L JAP -. . Jh a}}