ML20039E281
| ML20039E281 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/27/1976 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Goller K Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 8201070103 | |
| Download: ML20039E281 (10) | |
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's, UNITED STATES
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WA$HINGTON D. C. 20S55 hf e U
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!E.CPXiDU'I FOR:
K. R. Goller, Assistant Director for Operating Reactors, DOR FRC'!:
D. Eisenhut, Assistant Director for. 0perational' Technology, DOR SU3 JECT:
ROUND O!!E QUESTIONS - CASK DROP REPORT - THREE flILE ISIAND UNIT 1 - ORB-4-43
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Plant Name:
Three fule Island Unit 1 3 7 v' 3 3 Docket No:
50-289 Responsible Branch: ORB-4
Contact:
DrtWidges EW rT e.iq Gocna-D 6 MN
- fff7/r Requested Completion Date:
October 1,1976 (SER)
August 1,1976 (Queation Round One) (Verbal)
Necessary For Next Action: Response to staff concerns Review Status: Awaiting Response t
j Enclosed are the first round questions regarding the Three lille i
Island Unit 1 Report submitted February 17, 1976 entitled, Cask Drop Evaluation.
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&.L1, Eisenhut, Assistant Director D. G.
for Operational Technology Division of Operating Reactors
Contact:
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Fred Clemenson' NRR 128077
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Attachment:
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REQUEST F3.2 ;;~. TIO!1AL. I:iFO.:7ATION I
THREE : :*_I ISLA!!D UNIT 1 CASK 80 DROP !_':A I.:.:3 DOCKET 50-289-
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In regard to your le-er, dated February 14, 1976 and the i
attached Cask Drop Evaluation Report, we find that your analysis i
I and evaluation included small truck casks weighing 25 tons up to large rail casks weighing up to the rated capacity of the fuel handling crane of 110 tons. As you are aware, the shipping. cask lifting trunnions and yoke are generally designed to withstand i
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l come design load in excess of the weight of the cask.
However
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the cask handling craneTgenerally io4esigned>vrith two brakes) b y(:L
'TJ 5-cow each-eized with some cargin t.to hold 41oaJd equal-tcrthe Tating L%
o.%the-crane)..Fihich are autocatically set upon _ the loss of power.
You should assume, for the spectrum of the licensed shipping casks that you intend to handle over the life of the facility, including small casks such as the NFS-4 cask, that they are being lowered at the maximum speed allowed by the crane.
If you also assume a loss of power is experienced, thereby causing both of the crane hoist's automatically actuated brakes to be set, the deceleration load experienced by the cask handling yoke and trunnions will exceed that needed to statically hold the load.
Accordingly, for each cask, provide the following information:
4 ne s bd g_j (a) / factors of safety associated with the shipping cask handling yoke and trunnions and the corresponding a_. _ _
weight of the cask, v.
(b) the maximum speed as defined by the crane controls j
4 when raising and lowering the casks; and (c) the results of an analysip which demonstrates that the handling yoke and cask trunnions will have sufffeient design margin to preclude their failure due to the deceleration loads created by the hoist brakes, accuming the cask is being lowered at the I
limiting speed (as defined by the crane controls) when a loss of power to the crane is experienced.
2.
Your evaluation showed that during cask transfer to and from g
the transporter, " cask drops" could possibly result in unacceptable J1 ;.,folin a damage to engineered safeguards circuits. You--indiented that you plan to relocate one of the engineered safeguards circuit tray as a corrective measure.
(a) Since the movement of the cask will generally take place when the reactor is at power, assume:
(1) one of the engineered safeguards trays has been moved as you propose; (2) a cask drop occurs such as to disable one of the two separated engineered safeguards trays when the reactor is at power.
Under the above assumptions, describe, discuss and demon-strate that the single event (cask drop) will not initiate another event that potentially could place the reactor in an unsafe condition.
If such an event could occur it should also be assumed that a single failure may also occur in the f
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(;h systems associated with the remaining intact engineered s
safeguards tray.
4 d (b) Describe, discuss and demonstrate that in the event of
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a cask drop, that the interconnections between redundant
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channels of systems associated with the separated redundant
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i trays will not cause both systems to become non-functional tQ c
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if the cask drops on one of the two series of trays con-N*
4 M ~ hl taining the two redundant channels.
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H (c) In reference to the following" statements found in your.-
p.1_thl cd A t'+. a L report we will require.mdr4,d'of;initi'voFststemehts** -
clarificationrwhd.f 6-$pproprietc. before we can complete
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our review and evaluation.
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(1) "Accordingly we plan to relocate one engingered
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safeguard circuit tray...". $ D *'
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You "nlan to revise the cask transfer Aath..".
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I (3) Met Ed is currently evaluating poscible plant
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modifications and changes to operating procedures I
to correct"... cask drop accidents which could t
possibly result in unacceptable damage to ergineered safeguard circuits, spent fuel pool cooling pipes and cooling water pipes to the opent fuel pool coolers",
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(4) Met Ed'is currently evaluating the possibility C#
of relocating the cask decontamination area.
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In the, FSAR, Section 9.7.1, you state that when loads exceeding-
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'l$ tons n're being handled, an administratively imposed automatic travel interlock system will limit the range of travel of the loads to that shown in the FSAR-Figure 9-18A.
Assuming that:
(a) the 110 ton crane main hook has no load on it when it passes over a recently discharged batch of spent fuel elements; and (b) two-blocking of the main hoist load blocks occurs, provide an analysis which demonstrates either of the following: (1) the resulting radiological release will be within acceptable limits should the lower load block and hook drop onto the stored spent fuel; or I
(2) the lower load block and hook will not drop should two-b1ocking occur (in the latter case the analysis should to take into account
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the peak stall torque of the hoist motor plus the kinetic energy of the hoist power train and motor when the hook is being raised
's at its maximum rated speed as allowed by the control system).
(f In addition, describe and discuss any future modifications you a.r*p f
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may wish to malce regarding increasing the spent fuel pool storage
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l capacity by reducing the 21-1/8' y -
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between fuel assemblics and how this could affect the radiological"4 a #,[..
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release when a load is dropped.
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Describe and discuss the following with the aid of legible drawings:
~(a ) ;the path'[f theYentfuelshipi^gcaskasittravels between/thefollowinlgareas: th '//
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I(1 spent fue'1/ pool k.
f the'delcontamina-l transporte;andf3 storage' area; (2) t
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4a tion pit; (ct} (t) the engineered safeguards equipment and other equipment that may be required for a safe operation or cold shutdown of the reactor and whose operation may potentially be threatened,
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by a cask drop at any point along the travel path.s presented-(d t.-...q.<v.- :(uy ot. %.7.Xa.
in item (a-):above;.and y a-!-[
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(b) (th) assuming the most adverse combination of cask drop conditions, j
demonstrate by analysis that sufficient design margin exists to enable the staff to conclude that the resulting damage will-not endanger safe reactor operation and/or the facility's ability to attain and maintain a controlled, cold, safe reactor shutdown following a cask drop event at any point along its path of travel.
5.
The-infometionnontainM in San H nn 0 71.bof=the:FSAR is--in, suf41clent-to-estab11ohnthe ree of compliance of the fuel handling crane to Part D-2-c of Regu'.atory Guide 1.104',~" Overhead Crane 0
,83 Handling Systems For !!uelear Power Plants" Due toiyour statements regarding the bottom of the "B" spent fuel pool, the bottom of i
the decontamination pit and the floor slabs at elevation 348'-0",
331'-0", 305'-1" and 301'-6" not having been designed to with-stand the impact of a dropped cask, describe and discuss the 110 ton spent fuel shipping cask handling crane, incl"Aing its perfor-aJ <C mance requirements /' Demonstrate that it is or will be upgraded to comply with Part D-2-c of Regulatory Guide 1.104, prior to a
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['Ur; handling spent fuel shipping casks.
Further, provide your, schedule
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for the submittal. of any required modifications to NRC for review-and the schedule for completion of the modifications.
6.
You state that the height of the cask will be administrative 1y maintained at less than 1 foot above the top of the floor over which Ud
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it is traveling.
In regard to the above statement and the assumption f--
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of a cask drop, identify the particular spent fuel shipping casksifor-whiclrthe,above statement applies.
Describe and discuss the locations Ny
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.~. f ru. 2-4 % D -1) in the path of travel of the casksi here the strength of the structures j
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resisting the impact is the least; the margin of safety that precludes O
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its failure at these locations; and the essential equipment, located ls within the sphere of influence of a cask drop at these locations N
y (include the effects of spalled concrete), i.e., where tlief6,tiay~
,b'e damage or degraded performanceg eq U 24t>'#"'b '
7.
When the relocation of the cable trays that may be imperiled following a cask drop accident has been determined, provide:
(a) drawings showing the new location of the cable trays; (b) a list identifying each of the engineered safeguards and rea' tor protection e
system circuits associated with each of the relocated cable trays; and (c) a discussion which demonstrates the acceptability of the modifications assuming the loss of one of the redundant cable trays.
8.
In reference to the criteria that will be followed in making the modifications, the tollowing statement is made " Damage to multicolored circuits along with damage to circuits associated
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with one of those colors is acceptable since the multicolored s
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@Qs circuits are protected interconnections between two redundant channels." Provide further clarification which demonstrates the protected interconnections between two redundant channels will provide adequate protection in the event of: (a ) any open circuit, (b) any short circuit and (c) any short circuit between any two conductors that could develop as a result of a cask drop accident and thereby provide assurance that no more than one channel of redundant engineered safeguards system, or reactor protection system could be degraded or disabled.
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9.
Figure IV-3, showing t$.e modified cask transfer path and j
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new location for engineered safeguards tray, indicates that the rail car is located partially inside and partially outside the building during those times when the cask is being lifted from and lowered onto the rail car.
Describe and discuss what means will be provided to prevent the rail car position from being adversely altered during cask handling, such that it spans both the red and green cable trays, during a cask drop accident and thereby being in a position to cause damage to both redundant portions of engineered safeguards cable trays.
Further, describe, discuas and demonstrate that there are no.
significant adverse safety consequences resulting from having the heavy rolling door, shown in FSAR Figure 1-8 Section E1 -
E, open during these operations should a cask handling accident -
t occur.
Should the open doors pose a potential hazard to public henith and cafety, describe and discuss the possibility of
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Mn extending the structure and relocating the rolling door such as to
?l permit it to be closed during these operations.
10.
On page III-1 your report, you state "The height of the cask i
lower surface is administrative 1y maintained at less than 1 foot-above the top of the spent fuel pool walls (elevation 348'-0")".
On page IV-4, you state " Administrative procedures will be used to limit the height the cask lower surface is raised above the Qltyna.Q. wkr L A Iv r
top of the "B" spent fuel pool to 6 inches maximum." Since-the L wg.
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i Figures in-the-FSA and -your -pro md,f & -4 yat [mt MLg. posal indicates -the-tgof-the $2 *-] #"L p ce..;u u M A ~t**
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- Ch 1-Jc opent fuel pool is at elevation 348'l"p clarify w~ hat will-becA.% AL ' A (cJm r
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awa us-e the maximum carrying 1 eigh}h suukg *LL
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3 and potential dro y. < th b.sp A'u Ql "rM -
across-the-floor between -the spent fuel pool cask-storage area,--
. decontamination-pit-and - the - transporter.- Should - the carrying
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' height of the casks change r esubmit the results of-a-cask-drop r
analysis for-the corrected carrying-height above1he-floor; -
11.
In evaluating the consequences of a cask drop accident, I
l indicate for each spent fuel shipping cask if your analysis has i
taken credit for the action of the impact limiting devices attached to the cask when in its transportation configuration.
12.
The PSAR states the fuel handling crane is shared by Units 1 and 2.
Further, "A Ylhiting automatic paddle-type limit. switch
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is installed for upper hoist limit to prevent two-blocking situations." Assume:
(1) that he switch and/or its associated activating mechanism becomes Inoperative; and (2) the lower load block and hook are being raised at its maxima speed when l
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1 two-blocking occurs.
Under the above situation, provide the following information:
(a) A description of what provisions or ceasures have been provided to alert the operator at all times as to the status and functional capability of the switch and associated actuating mechanism; and (b) A demonstration by analysis that when taking the maximum peak torque of the hoist motor and the kinetic energy of the power I
train and motor rotor into account, a fcilure will not occur v;hich could result in dropping the lower load block and hook.
13.
Since the 110 ton fuel handling crane will be shared by Units 1 and 2, describe, discuss and evaluate all safety related facility design considerations of Unit 1 that will differ from those that will exist in Unit 2 as they relate to spent fuel cask drop accidents.
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