ML063330083
| ML063330083 | |
| Person / Time | |
|---|---|
| Site: | Washington State University |
| Issue date: | 11/16/2006 |
| From: | Wall D Washington State Univ |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML063330083 (6) | |
Text
WASHINGTON STATE JU UNIVERSITY Nuclear Radiation Center November 16, 2006 Docket # 50-027 Document Control Desk US Nuclear Regulatory Commission Washington, DC 20555-0001 This notification is submitted per 10CFR50.54 and 10CFR50.59.D.2 During September 2006, the existing temperature indication system installed at the Washington State University (WSU) Nuclear Radiation Center was upgraded to a modem digital system. All components and wiring downstream of the existing thermocouples were replaced. This change was approved by our Reactor Safeguards Committee in December of 2005.
Attached is a review of the 50.59 criteria of this modification. The overall safety and performance of the reactor and associated safety systems is enhanced by the upgrade.
The reactor was returned to power after the new temperature indication system was installed and fully tested. All systems and associated parameters continue to perform as expected and indicate normal operating conditions.
If you have any comments or questions, please contact me at 509-335-0172.
Sincerely, Dr. Donald Wall Director, WSUNRC Cc: Marvin Mendonca, Project Manager PO Box 641300, Pullman, WA 99164-1300 A 509-335-8641 o Fax: 509-335-4433 - www.wsu.edu/-nrc
A. SHORT DESCRIPTION OF PROPOSED CHANGE The proposed change to the facility involves removing the current core temperature monitoring system and replacing it with a new Omega temperature indication and control system.
B. EVALUATION TO DETERMINE IF THE PROPOSED MODIFICATION INVOLVES A TECHNICAL SPECIFICATION CHANGE OR MEETS 10 CFR 50.59 CRITERIA.
- 1. THE PROPOSED CHANGE DOESNOT INVOLVE A CHANGE TO THE TECHNICAL SPECIFICATIONS The requirements for reactor monitoring channels and safety settings are listed in section 3.6.2 of the technical specifications. The requirements and proposed changes are listed below in Table 1. The requirements for reactor safety systems are listed in section 3.6.3 of the technical specifications. These requirements and the proposed changes are listed in Table 2. Since the change does not involve reducing these numbers to below the technical specification limits, the change meets this criteria.
Table 1. Measuring Channels Measuring Tech. Spec. Current Proposed Channel Requirement Number Change Steady State Mode Fuel temperature' 1 2 No Change Linear power level 1 2 No Change Log power level 1 1 No Change Pulse Mode Fuel temperature 1 2 No Change Integrated pulse power 1 2 No Change
- 1. This installation will remove the existing fuel temperature indication system and replace them with modern Omega thermocouple indications and controls. The in-core thermocouples will remain in place and will connect to the new indications. All technical specifications are met.
Table 2. Reactor Safet Channels Safety Channel Function Tech. Spec. Current Proposed Requirements Number Change Steady State Mode Fuel temperature SCRAM at 500'C 1 2 No Change Power level SCRAM at 125% 1 2 No Change Manual SCRAM Manual SCRAM 1 1 No Change Wide Range Low count rate 1 1 No Change inhibit High Voltage SCRAM on loss of 1 All No Change Monitor High Voltage channels Pool level Alarm at 16' 1 1 No Change Transient rod Prevent air 1 1 No Change control application unless fully inserted Pulse Mode Fuel temperature SCRAM at 500'C 1 2 No Change Manual SCRAM Manual SCRAM 1 1 No Change Wide range High Power Pulse 1 1 No Change inhibit High voltage SCRAM on loss of 1 All No Change monitor high voltage channels Pulse mode switch Prevent standard 1 1 No Change rod withdrawal in pulse mode' Preset timer Transient rod 1 1 No Change SCRAM within 15s after pulse Pool level Alarm at 16' 1 1 No Change
- 2. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE FREQUENCY OR OCCURENCE OFANACCIDENT PREVIOUSLY EVALUATED IN THE FSAR (AS UPDA TED).
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. (Fuel failure in air.)
Several factors affect the possibility of fuel failure, including the possibility of instrument failure. The installation of the new instruments will increase the overall reliability of the temperature indication and control system and will be less prone to fail.
This will result in an overall safety increase.
- b. The loss of coolant accident.
Coolant loss is not a result of a failure in power instrumentation. Cooling and pool level systems will remain unchanged.
- c. Accidental fuel addition.
Fuel addition is not a function of console controls or fuel temperature indication.
- d. Accidental Pulse rod ejection.
The modification of the fuel temperature system has no interconnections with the pulse rod 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 indication will directly replace the current indication, and will be hooked up to the SCRAM chain accordingly.
- 3. THE PROPOSED CHANGE SHALL NOT RESULTIN MORE THAN A MINIMAL INCREASE IN THE LIKELIHOOD OCCURRENCEOF A MALFUNCTION OFA STRUCTURE, SYSTEM, OR COMPONENT (SSC)IMPORTANT TO SAFETY PREVIOUSLY EVALUATED IN THE FSAR (As UPDATED).
The installation of the new temperature indication system will decrease the possibility of a malfunction of a SSC, resulting in the overall increase in safety and reliability.
- 4. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE CONSEQUANCES OFAN ACCIDENT PREVIOUSLY EVALUA TED IN THE FSAR(As UPDATED).
Instrumentation changes in the console should have no effect on the consequences of a postulated accident, as described in Appendix A of the WSUNRC SAR.
- 5. THE PROPOSEDCHANGE SHALL NOT CREA TE A POSSIBILITY FOR AN ACCIDENT OFA DIFFERENTTYPE THAN ANY PREVIOUSLY EVALUA TED IN THE FINAL SAFETY ANALYSIS REPORT (AS UPDATED).
The replacement components have the same failure modes as the previous instrumentation. Therefore, no new accidents are postulated.
- 6. THE PROPOSEDCHANGE SHALL NOT CREATE A POSSIBILITY FOR A MALFUNCTION OFAN SSC IMPORTANT TO SAFETY WITH A DIFFERENTRESULT THAN ANY PREVIOUSLY EVALUATED IN THE FSAR (AS UPDATED).
An instrument failure of this type would lead to the same scenario as a failure of the current instrumentation,namely incorrect fuel temperature indication. This mode of failure has already been evaluated and no additional problems or consequences are foreseeable with newer instrumentation.
- 7. THE PROPOSEDCHANGE SHALL NOT RESULT INA DESIGN BASIS LIMIT FOR A FISSION PRODUCTBARRIER AS DESCRIBEDIN 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. In normal operation, none of these limits will by exceeded by this upgrade.
- 8. THE PROPOSED CHANGE WILL NOT RESULTIN DEPARTURE FROMA METHOD OF EVALUATION DESCRIBEDIN THE FSAR (AS UPDA TED) USED IN ESTABLISHING THE DESIGN BASES OR IN THE SAFETY ANALYSIS.
Upgrade of the temperature indication system does not cause a departure from methods of evaluation described in the SAR.
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C. 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). This proposal was reviewed and approved by the RSC in December of 2005.
RSC Approval: o
/1--11'-0 D. 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.
Eric Corwin, Reactor Supervis r Dr. 5* onald Wall, Director