ML11356A085

Written Communication Regarding University of Missouri - Columbia - Request for Additional Information, License Amendment, Center Test Hole

ML11356A085
Person / Time
Site:	University of Missouri-Columbia
Issue date:	12/19/2011
From:	Fruits J L, Butler R A Univ of Missouri
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC ME1876
Download: ML11356A085 (6)

Text

UNIVERSITY of MISSOURIRESEARCH REACTOR CENTERDecember 19, 2011U.S. Nuclear Regulatory CommissionAttention: Document Control DeskMail Station PI-37Washington, DC 20555-0001 1REFERENCE: Docket 50-186University of Missouri-Columbia Research ReactorAmended Facility License R-103SUBJECT: Written communication regarding "University of Missouri -Columbia -Request forAdditional Information, Re: License Amendment, Center Test Hole (TAC No.ME1876)"By letter dated August 6, 2009, the University of Missouri-Columbia Research Reactor (MURR)submitted a request to the U.S. Nuclear Regulatory Commission (NRC) to amend the TechnicalSpecifications, which are appended to Facility License R-103, that would authorize the implementation ofan engineered safety device that would prevent operation of the reactor unless the center test hole canisteror strainer is inserted and latched onto the inner reactor pressure vessel. Approval of this Amendmentwould allow greater flexibility and capacity in the center test hole for the irradiation of high specificactivity radioisotopes that are used for radiopharmaceutical research and cancer treatments.By letter dated June 1, 2010, as part of the facility license renewal process, the NRC requested additionalinformation and clarification regarding the proposed Amendment in the form of seven (7) questions. Byletter dated August 31, 2010, the MURR responded to those questions.By letter dated December 27, 2010, the NRC requested additional information and clarification regardingthe proposed Amendment in the form of five (5) questions. By letter dated January 31, 2011, the MURRresponded to those questions.On July 1, 2011, the NRC requested additional information and clarification regarding the proposedAmendment in the formn of four (4) questions. By letter dated July 11, 2011, the MURR responded tothose questions.On December 15 and 16, 2011, by telephone and electronic mail (e-mail), the NRC (Alexander Adams,Jr., Senior Project Manager) requested clarification on the usage of the "center test hole Strainer" and itsrelationship to the Technical Specifications (TS). Enclosed is a more detailed description of the Strainerand revised TS pages based on this discussion.'W1513 Research Park Drive Columbia, MO 65211 Phone: 573-882-4211 Fax: 573-882-6360 Web: www.murr.missouri.eduFighting Cancer with Tomorrow's Technology If there are any questions regarding this response, please contact me at (573) 882-5319. I declare underpenalty of perjury that the foregoing is true and correct.Sincerely,John L. FruitsReactor ManagerENDORSEMENT:Reviewed and Approved,Ralph A. Butler, P.E.DirectorAttachments: 1. Revised Technical Specification 3.3, Pages 3 of 5 and 5 of 5xc: Reactor Advisory CommitteeReactor Safety SubcommitteeDr. Robert Duncan, Vice Chancellor for ResearchMr. Craig Basset, U.S. NRCMr. Alexander Adams, U.S. NRCMMRGE P. STWUMy0=*um~s~nE~INMudi24,2012-1'2 of 4 The center test hole Strainer is briefly described on Page 2 of the original application, dated August 6,2009, to Amend the Technical Specification appended to Facility License R-103. The Strainer is installedto preclude the possibility of any foreign objects from entering the flux trap region if the reactor isoperated without the Center Test Hole Canister inserted. The Strainer latching mechanism is of the exactsame design as that of the Center Test Hole Canister. When installed, the Strainer is positivelydetermined by a latching mechanism located at the top of the assembly. The latching mechanism consistsof two Inconel or Stainless Steel fingers which secure the Strainer to the upper portion of the inner reactorpressure vessel. The fingers, which are attached to the upper section (head piece) of the Strainer by four(two per finger) countersunk, stainless steel screws, are positioned 180 degrees apart and are totallyindependent of one another. The Strainer latching mechanism has not been modified or altered from itsoriginal design and no failures have occurred in the nearly 45 years of operation.Center Test Hole StrainerOne of Two Latching FingersInner ReactorPressure Vessel"Reactor PressureVessel HeadAs described on Page 5 of the responses, by letter dated July 11, 2011, to the Request for AdditionalInformation (RAI), a special removal tool, with an overall length of approximately 20 feet, is required tounlatch and remove the center test hole canister from the inner pressure vessel. The head of the removaltool must be inserted into the center test hole canister wear ring in order to spread the latching fingers3 of 4 sufficiently to disengage the canister from the inner pressure vessel. This same tool is also used toremove the Strainer from the inner pressure vessel.The overall length of the center test hole Strainer is only 7 inches; therefore it does not enter into the fluxtrap region of the core and hence there is no reactivity contribution to the reactor when it is installed.Essentially, the only time that it is used is to perform reactivity measurements of the center test holecanister (empty and with experiments loaded) at very low powers (at or below 50 kW, or less than 0.5%of the MURR full core power level of 10 MW). Reactivity measurement methodology was previouslydescribed in detail in the response to Question 10.5.e, by letter dated August 31, 2010, from therelicensing RAIs, by letter dated June 1, 2010.Below are two photographs of the center test hole Strainer.4 of 4 TECHNICAL SPECIFICATIONUNIVERSITY OF MISSOURIRESEARCH REACTOR FACILITYNumber 3.3Page 3 of 5DateAmendment No.SUBJECT: Reactor Safety System (continued)Manual Scram 1 1 1 Push Button at Control ConsoleCenter Test Hole 2(6) 2(6) 2(6) Scram as a result of removing the center testhole removable experiment test tubes or strainer(I) Flow orifice or heat exchanger AP (psi) in each operating heat exchanger legcorresponding to the flow value in the table.(2) Not required below 50 KW operation if natural convection flange and pressurevessel cover are removed or in operation with the reactor subcritical by amargin of at least 0.0 15 AK.(3) Trip pressure is that which corresponds to the pressurizer pressure indicatedin the table with normal primary coolant flow.(4) Flow orifice AP (psi) corresponding to the flow value in the table.(5) Core AP (psi) corresponding to the core flow value in the table.(6) Not required if reactivity worth of the center test hole removable experiment test tubes and itscontents or the strainer is less than the reactivity limit of specification 3.1 .h. This safety functionshall only be bypassed with specific authorization from the Reactor Manager.Basesa. The specifications on high power, primary coolant flow, primary coolant pressure,and reactor inlet temperature provide for the safety system settings outlined inspecifications 2.2.a, 2.2.b, and 2.2.c. In Mode I and II operation the coredifferential temperature is approximately 17 F.

TECHNICAL SPECIFICATIONUNIVERSITY OF MISSOURIRESEARCH REACTOR FACILITYNumber 3.3Page 5 of 5DateAmendment No.SUBJECT: Reactor Safety System (continued)The scrams from the primary and pool coolant isolation valves (507A/B and509) leaving their full open position provide a first line of protectionfor a loss of flow accident in that system initiated by an inadvertentclosure of the isolation valve/s.The power level interlock (PLI) scram provides assurance that the reactorcannot be operated with a power level greater than that authorized for themode of operation selected on the Mode Selector Switch. The PLI scram alsoprovides the interlock to assure that the reactor cannot be operated inMode I with a pool or primary coolant flow scram by-passed.The facility evacuation and reactor isolation scrams provide assurance thatthe reactor is shutdown for any condition which initiates or leads to theinitiation of an evacuation or isolation.The manual scram provides assurance that the reactor can be shutdown by theoperator if an automatic function fails to initiate a scram or if the opera-tor detects an impending unsafe condition prior to the automatic scraminitiation.The center test hole scram provides assurance that the reactor can not beoperated unless the removable experiment test tubes or the strainer is insertedand latched in the center test hole. This is required any time the reactivityworth of the center test hole removable experiment test tubesand the contained experiments or the strainer exceeds the limit of specification 3.1 .h.(Ref. Section 3.5 of Add. 3 to HSR). The center test hole scram may bebypassed if the total reactivity worth of the removable experiment test tubesand the contained experiments or the strainer does not exceed the limit of specification 3.1 .hand is authorized by the Reactor Manger.