ML19260A102
| ML19260A102 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/18/1977 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Herbein J METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7910290721 | |
| Download: ML19260A102 (13) | |
Text
AUG 11 1977 DISTRIBUTJON:
Docket V NRC PDR L PDR ORB #4 Rdg.
TCarter J o c L e t ':c. 5 0 - 2 r.o VStello SHosford KRGoller FClemenson OELD OIAE(3)
RWReid
?'etrooolitan Edison Comany
.,Zwetzig ATTN:
Mr. J. G. Herhein RIngram Vice President DEisenhut P. O. Box 542 ath Readino, Pennsylvania 19603 nan ACRS(16)
Gentleren:
Gray file Rylletter dated February 14,197F, you submitted an analysis of a postulated Spent Fuel Cask Drop in the vicinity of the "B"
Spent Fuel Pool at Three ' tile Island Nuclear Generatino Station, t' nit No. 1 (T"I-1).
By letter dated Scotember 21, 1976, you submitted a request for aimndmnt of the TMI-1 Technical Specifications in-tended to address considerations raised by your analysis.
In order that we ray continue our review of this natter we find we need additional infomation. The snecific infomation needed is listed in the enclosure. You are requested to submit the infornation listed in the enclosure within 60 days of receipt of this letter.
Sincerely,
'D D
L Robert 11. Reid. Chief Operating ?.eactors 3 ranch f4 Division of Operatino Reactors
Enclosure:
Request for Additional Inforratien cc w/ enclosure:
1479 325 See next pace
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Form AEC 333 (Rev. 9 53) AICM 0240 W u. s. sova nanesar rainvi=a orrican ter.s.sas.tes
,79102907 2 / /8
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' Metropolitan Edison Company cc:
G. F. Trowbridge, Esquire Shaw, Pittman, Potts & Trowbridge 1800 M Street, N. W.
Washington, D. C.
20036 GPU Service Corporation Richard W. Heward, Project Manager Thomas M. Crimmins, Jr., Safety and Licensing Manager 260 Cherry Hill Road
,Parsippany, New Jersey 07054 Pennsylvania Electric Company Mr. R. W. Conrad Vice President, Generation 1001 Broad Street Johnstova, Pennsylvania 15907 Mr. Weldon B. Arehart, Chairman Board of Supervisors of Londonderry Township RFD#1, Geyers Church Road Middletown, Pennsylvania 17057 Miss Mary V. Southard, Chairman Citizens for a Safe Environment P. O. Box 405 Harrisburg, Pennsylvania 17108 Government Publications Section State Library of Pennsylvania Box 1601 (Education Building)
Harrisburg, Pennsylvania 17126 1479 326
RE0 VEST FOR ADDITIONAL INFORMATION THREE MILE ISLAND UNIT 1 CASK DROP ANALYSIS DOCKET NO. 50-289 1.0 The Cask Drop Evaluation for Three Mile Island Unit 1 (TMI-1),
enclosed with your February 14, 1976 letter, states:
(1)
"During transfer of the cask to and from the decontamination pit and raising and lowering of the cask within the pit, results of evaluations indicate that with the present system, cask drop accidents could possibly result in unacceptable damage to engineered safeguard circuits, spent fuel pool coolant pipes, and cooling water pipes to the spent fuel pool coolers. Met Ed is currently evaluating possible plant modifications and changes to operating procedures to correct this situation " and (2)
"When the location for cask decontamination operations is selected, the specific plant modifications and changes to operating procedures and technical specifications that are required will be described to NRC. Until such time, the present cask decontamination pit will not be used."
The discussion supporting the the proposed changes to the Technical Specifications transmitted by your letter of September 21, 1976 states that as a result of your stadies, it is new proposed to relocate the cask decontamination area in the shaded area shown 1479 327
2 in Figure 3.11-3 of your September 21, 1976 submittal.
- Further, FSAR Figure 1-3 shows that the Unit 1 temporary new fuel storage area is located parallel to the transporter railroad tracks and could be in the path of the spent fuel cask as it travels to and from the Unit 1 decontamination area as well as the corresponding work stations in Unit 2.
It is expected that an incoming empty shipoing cask will be moved from the transporter to the decontamination area for cleaning before being moved to the loadinc pit.
For the Unit I loaded cask, it is possible that it will be noved from the cask storage and loading pit across the railroad tracks and again over the temporary new fuel storage area to the decontamination area for decontamination before being loaded on to the transporter.
To enable us to continue our review and evaluation of the safety implications of the Unit 1 proposed changes, once the shipping cask and transporter has entered the Unit 1 building for the offsite shipment of fuel from either Unit 1 or Unit 2, we will require the following additional information.
1.1 Provide one drawing showing the relative location of the following areas of Unit 1:
(i) the new fuel storage areas; (ii) the spent fuel storage pool; (iii) the spent fuel cask storage and loading pit; and (iv) the specific location of the cask decontamination area.
1479 328 1.2 To adequately evaluate the potential for unsafe conditions occurring in Unit 1 following a cask drop accident at any point along its revised path of travel between the transporter, the newly located decontamination area, and the spent fuel cask loading pit, superimpose the travel paths of the shipping cask for Unit 1 end 2 within the Unit 1 building on the drawing requested above.
1.3 Verify that the path of travel of the spent fuel cask from the transporter to the Unit 2 building has not changed due to these proposed changes or describe, discuss and demonstrate that no safety related consequences could result from these changes.
1.4 Assuming the engineered safeguard circuit trays have been relocated as proposed in Figures IV-3 and IV-4 (February 14, 1976 submittal) and a cask drop accident occurs such
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as to disable one of the two seoarated engineered safeguard trays when the reactor is at power.
Provide the following information:
(a) Describe, discuss, and demonstrate tnat the single event (cask drop), at any point along its path of travel, will not initiate another event that potentially could prevent a safe reactor shutdown or prevent adequate spent fuel cooling.
Your analys'., should assume a single failure in the systems associated
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'7' with the remaining intact engineered safeguards tray or other essential systems but may include use of non-safety grade equipment.
Where possible, reference the appropriate Figures in the FSAR which show the location of threatened equipment.
(b)
In reference to the criteria that will be followed in making the modifications, the following statement is made " Damage to multicolored circuits along with damage to circuits associated with one of those colors is acceptable since the multicolored circuits are protected interconnections between two redundant channels." Provide further clarification which demonstrates that 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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2.0 It is stated in your submittal that:
(1) the cask will be handled above and adjacent to engineered safeguard equipment; 1479 330
. (2) the floor slabs are not designed to withstand the impact of a dropped cask; (3) cask sizes considered in the evaluation included small truck casks weighing approximately 25 tons up to the large rail casks weighing up to the rated capacity of the fuel handling crane of 110 tons.
2.1 Based on the most adverse combination of cask drop conditions, at all points along its revised path of travel with',n the Unit i building, demonstrate by an. lysis that sufficient design margin exists to enable the staff to conclude that, for the specific shipping casks considered, the resulting damage will not preclude the facility's essential equipment (such as pumps, piping, vaives, and electrical trays) from attaining and maintaining a controlled, cold safe
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reactor shutdown.
Where structures are found to withstand the impact of the cask drep, present the input parameters assumed in the analysis including:
cask weight, cask impact area, drop heigh:, drop location, and the assumptions regarding credit taken in the analysis for the action of impact limiters.
- 2. 2 Demonstrate that following a cask drop accident the cask
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will not tip, roll, or impact on Unit 1 temporarily stored new fuel in a manr.er which would lead to a 1479 531
. criticality accident.
In particular, state a maximum credible value for the multiplication factor (Xeff) following such a cask dap accident consi-dering the effects of any possible reduction in fuel spacing, with the introduction of neutron moderating material (aqueous foam, water from ruptured pipes or fire-fighting apparatus, etc. ).
This maximum credible value should include reflective effects from structural concrete and any other moderating materials near the fuel mass. Provide the assumptions made in the analyses and the resulting safety margins which support your conclusions.
3.0 For each of the spent fuel shipping casks that will be handled, demonstrate that the crane hoist will not subject the various cask trunnions and handling yokes, considered in your evaluation, to excessive deceleration loads under the following assumptions:
(1) the cask is near its upper limit of travel; (2) the cask is being lowered at its maximum speed as defined by the hoist controls; and (3) the crane experiences a loss of power thereby causing the hoist mechanical: load brake and the solenoid brake to automatically set.
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. Accordingly, in tabular forn for each cask, provide the following information:
(a) the static factors of safety of the cask handling yoke, the cask trunnions and the weight of cask; (b) the maximum lowering speed as defined by the hoist controls; and (c) the results of dynamic analyses which demonstrate that the cask trunnions and handling yoke have sufficient design margin to preclude their failure due to the deceleration loads created by the hoist brakes.
4.0 It has been noted that the bases provided in your September 21, 1976 submittal for Item 3.11.2 of the revised Technical Specifications has emitted reference to FSAR Figure 9-18A entitlted " Fuel Handling Building Crane Key Interlock System Limits".
Provide a revised Figure 9-18A showing the new key interlocked limits of travel of the crane.
Further, the basis for the present Technical Specification states that in the "unlikely event of a load drop accident, there would be no possibility of this resulting in any damage.....".
The proposed corresponding statement in the revised Technical
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Specification basis states there "would be less possibility."
Describa, discuss and clarify the purpose of this revision and the potential equipment and structures involved.
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.- 5.0 Since the keyed interlock limits of crane travel only applies when the load being handled exceeds 15 tons, provide the following information regarding the system acceptability when there is a load of 14 tons on the crane hook, and it is over the stored spent fuel when "two blocking" occurs (i.e., the upper limit switch fails and the lower hoist block contacts the lower block).
Demonstrate that either (a) the resulting radiological release will remain within acceptebie limits should the lower load block and hook drop and impact on the stored spent fuel; or (b) the lower load block and hook will not drop should "two blocking" occur.
(In the latter case, the analysis should take into account the peak stall torque of the hoist motor clus the kinetic energy of the hoist power train and motor when the hook is being raised at its maximum rated speed as allowed by the control system).
6.0 In regard to the shipping cask crane which is shared by Units 1 and 2, it has been noted that the staff's Safety Evaluation Report for tinit 2, dated September 1976, contains the following statement "We 1md the fuel handling system to be acceptable for a cask not exceeding 70 tons in weight, and will :endition the operating license accordingly until and unless th! applicant justifies use of a larger cask." 3ection 3.11.4 ef the Unit 1 Technical Specifications would permit the crane to handle loads up to 110 tons since it states " Loads in excess of hook capacity shall not be lifted, except for load testing."
1479 W
9 Describe and discuss any differences which exist between Units I and 2 as it relates to cask drop accidents.
Further, the depth of detsti provided should enable the reviewer to concur in the acceptability of 110 ton loads for the c.'ane when they are being handled in the Unit 1 facility.
7.0 Figure IV-3, (February 14, 1976 submittal) showing the modified cask transfer path and new location for engineered safeguards tray, indicates that the rail car is located 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 a cask handling accident, such that it spans both the red and green cable trays during a cask drop accident and thereby being in a position to potentially cause damage to both redundant portions of the engineered safeguards cable trays.
8.0 Since the rail car will be partially outside the building during cask handling operations, describe, discuss and demonstrate that there are no significant adverse safety consequences resulting from having the heavy rolling door, shown in FSAR Figure 1-8, Section El - E], open during such operations involvinj the offsite shipment of spent fue' from either Units 1 or 2 should a cask
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. handl1ng accident occur.
Should the open doors result in a potential hazard to public health and safety, describe your proposed corrective measures.
9.0 On Page IV-4, of your February 14, 1976 submittal, you snte
" Administrative procedures will be used to limit the height the cask lower surface is raised above the top of the "B" spent fuel pool to 6 inches maximum" Proposed Technical Specification 3.11.3 also makes a related reference to administrative contrcl of load elevation.
Clarify what will be the carrying height of the cask bottom surface, with respect to fixed structures, at all points along tne path of travel of the spent fuel shipping cask while it is within the building.
What are the measures, in addition to administrative controls, which could be incorporated to preclude cask drop heights exceeding the above carrying heights.
10.0 Provide proposed Technical Specifications for crane rope inspection and replacement and for assuring operability of the limit switches which restrict crane travel. Use the appropriate corresponding parts of chapter 2-2 of the American National Standards Institute ANSI 520.2 for guidance in preparing your response.
11.0 The FSAP states "A Whiting automatic paddle-type limit switch is installed for upper hoist limit to prevent "two-blocking" situatiuns." 5escribe the design features or pror.edures that will be used to provide assurance that a single failure will not defeat this protection against "two-blocking".
1419 W
. 12.0 provide a summary of the cask stability analysis when the cask is dropped on the south wall cf the "B" spent fuel pool for both eccentric and straight drop conditions.
13.0 Show that the liner plate will not tear if the east wall of the loading pit deflects 1" as postulated in Section IV-B-3.
Also discuss the effects on the' fuel racks which are in contact with the east wall due to the 1" deflection.
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