ML090220221
| ML090220221 | |
| Person / Time | |
|---|---|
| Site: | Washington State University |
| Issue date: | 01/08/2009 |
| From: | Wall D Washington State Univ |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML090220221 (5) | |
Text
WASHINGTON STATE M UNIVERSITY Nuclear Radiation Center January 08, 2009 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Re: Docket Number 50-027 A new transient rod (reactor control element number three) was installed in the Washington State University 1 MW TRIGA nuclear reactor. The installation of the replacement control rod and connecting rod has been reviewed and approved by the Washington State University Reactor Safeguards Committee.
The control rod was supplied by General Atomics, and was installed during the course of converting the reactor from HEU to LEU fuel. The new control rod conforms to specifications in dimension and performance that were applicable to the previous control rod.
A review of the 10 CFR 50.59 criteria for the control rod change is included as an attachment.
The functionality of the reactor control system will not reduce the safety or performance of the reactor and associated systems.
This letter is submitted in accordance with 10 CFR 50.54 and 10 CFR 50.59 (d)(2).
Please contact me at (509) 335-8641 if there are any comments or questions Respectfully Submitted, Donald Wall, Phi.D.
Director Nuclear Radiation Center Washington State University P.- Box641300, Pullman, WA 99164-1 300 509-335-8641
- Fax: 509-335-4433
- www.wsu.edu/nrc
- )
.50.59 Transient Rod 12/3/2008 PROPOSED CHANGE PER 10 CFR 50.59: DIRECT REPLACEMENT OF THE TRANSIENT ROD & PARTIAL REPLACEMENT OF THE CONNECTING ROD A. SHORT DESCRIPTION OF PROPOSED CHANGE The proposed change to the facility involves removing the existing transient rod (pulse rod) and replacing it with a new unit manufactured by General Atomics with the same specifications. The section of the connecting rod directly attached to the transient rod could not be reused and was fabricated in house with the exact specifications obtained from the old transient rod hardware section.
Also, the sections of the older connecting rod were assembled with lock washers and bolts. These were replaced with lock nuts and hex bolts for added strength and reliability.
- B. EVALUATION TO DETERMINE IF THE PROPOSED MODIFICATION INVOLVES A TECHNICAL SPECIFICATION CHANGE OR MEETS 10 CFR 50.59 CRITERIA.
- 1. THE PROPOSEDCHANGE DOES NOT INVOLVE A CHANGE TO THE TECHNICAL SPECIFICATIONS The direct replacement of the transient rod itself, with the reuse of the previously utilized upper section of the connecting rod, guide tube, and associated hardware does not change the action of the transient rod.
Therefore, this replacement does not involve changing the Technical Specifications.
- 2. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE FREQUENCY OR OCCURENCE OFAN ACCIDENT PREVIOUSLY EVALUATED IN THE FSAR (As UPDATED).
There are four major accidents considered in the SAR. These are:
the design base accident (fuel failure in air), a loss of coolant accident, an accidental fuel addition, and the accidental ejection of the pulse rod. Each is evaluated below.
- a. The design base accident given by fuel failure in air.
This replacement will not increase the frequency or occurrence of an accident previously evaluated in the FSAR.
- b. The loss of coolant accident.
Replacement of the transient rod is not linked to the cooling system or pool. The cooling and pool level systems will remain unchanged.
- c. Accidental fuel addition.
Fuel addition is not a function of the transient rod or connecting hardware.
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50.59 Transient Rod 12/3/2008
- d. Accidental Pulse rod ejection.
The replacement of the pulse rod poison section and connecting hardware does not require any change in the console control interlocks.
In addition to these postulated accidents, the SAR gives criteria for meter installation including: readability, ease of use, and connection to the SCRAM chain. The new transient rod and connecting hardware directly replaces the old components and has no direct connection to the Reactor Protection Systems.
- 3. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE LIKELIHOOD OCCURRENCE OFA MALFUNCTION OFA STRUCTURE, SYSTEM, OR COMPONENT (SSC)IMPORTANT TO SAFETY PREVIOUSLY EVALUATED IN THE FSAR (AS UPDATED).
The installation of the new pulse rod with the new connecting hardware replaces the older connecting hardware with stronger, more robust parts. Specifically, the replacement of lock washers with lock bolts in the connecting rod linkage is an upgrade to the previous hardware. This will in turn decrease the possibility of a malfunction of an SSC, resulting in the overall increase in safety and reliability.
- 4. THE PROPOSEDCHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE CONSEQUENCES OFANACCIDENT PREVIOUSLY EVALUATED IN THE FSAR (As UPDATED).
The direct replacement of the transient rod and connecting hardware will have no effect on the consequences of a postulated accident, as described in Appendix A of the WSUNRC SAR.
- 5. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE CONSEQUENCESA MALFUNCTION OF A SSC IMPORTANT TO SAFETY PREVIOUSLY EVALUA TED IN THE FSAR (AS UPDA TED).
An increase in the consequences of an SSC malfunction from the previously evaluated in the FSAR are not anticipated due to the direct replacement of the pulse rod and connecting hardware.
- 6. THE PROPOSED CHANGE SHALL NOT CREA TE A POSSIBILITY FOR AN ACCIDENT OFA DIFFERENTTYPE THAN ANY PREVIOUSLY EVALUATED IN THE FINAL SAFETY ANALYSIS REPORT (AS UPDATED).
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50.59 Transient Rod 12/3/2008 The direct replacement components are no different in function or specifications than in the previous components. Therefore, no new accidents are postulated.
- 7. THE PROPOSED CHANGE SHALL NOT CREA TE A POSSIBILITY FOR A MALFUNCTION OF AN SSC IMPORTANT TO SAFETY WITH A DIFFERENTRESULT THAN ANY PREVIOUSLY EVALUATED IN THE FSAR (AS UPDATED).
The installation of the new pulse rod and connecting hardware will decrease the possibility of a malfunction of an SSC, resulting in the overall increase in safety and reliability. The installation is a direct replacement; therefore the creation of an SSC failure with a different result than previously evaluated is not anticipated.
- 8. THE PROPOSED CHANGE SHALL NOT RESULT IN A DESIGN BASIS LIMIT FOR A FISSION PRODUCTBARRIER AS DESCRIBED IN THE SAR BEING EXCEEDED OR ALTERED.
The design limits for this reactor, as listed in section 6.3 of the SAR are: shutdown margin limit, reactivity addition rate limit, fuel operating temperature limit, operating power limit, reactivity addition during pulsing, and the various fuel inspection limits. None of these limits will by exceeded by this upgrade during normal operation.
- 9. THE PROPOSED CHANGE WILL NOT RESULT IN DEPARTURE FROMA METHOD OF EVALUATION DESCRIBED IN THE FSAR (AS UPDA TED) USED IN ESTABLISHING THE DESIGNBASES OR IN THE SAFETY ANALYSIS.
The installation of the new pulse rod and connecting does not cause a departure from methods of evaluation described in the SAR.
C. RECOMMENDATION This change meets the criteria for an acceptable change under 10 CFR 50.59 criteria. I hereby submit this proposal for review by the Facility Director and the RSC. Should there be any more question or comment, please feel free to contact the facility.
C. Corey, -ines Reactor Supervisor, WSUNRC Donald Wall Director, WSUNRC 3
. . 11-50.59 Transient Rod 12/3/2008 D. DETERMINATION OF RSC REVIEW NECESSITY Under current procedures, changes to the facility, as described in the SAR, must be approved by the Reactor Safeguards Committee (RSC), and in this case can be done after the change is made. This proposal was reviewed and approved by the RSC on December 3, 2008 Gary Thorgaard Chair, Reactor Safeguards Committee 4