ML070320140
| ML070320140 | |
| Person / Time | |
|---|---|
| Site: | Washington State University |
| Issue date: | 01/24/2006 |
| From: | Wall D Washington State Univ |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML070320140 (6) | |
Text
. i Washington State University Nuclear Radiation Center PO Box 641300 Pullman, WA 99164-1300 509-335-8641 FAX 509-335-4433 January 24, 2006 Docket # 50-027 Document Control Desk US Nuclear Regulatory Commission Washington, DC 20555-0001 In September 2006, the existing temperature indication system installed at the Washington State University Nuclear Radiation Center was replaced with a modem equivalent. As approved by our Reactor Safeguards Committee in December of 2005, the system is a drastic improvement in the operability and performance of the temperature indication system..
Attached is the review of the 50.59 criteria of the system change. As installed, there is no reduction in the safety or performance of the reactor and associated systems.
This notification is submitted per 10CFR50.54 and 10CFR50.59.D.2 After the new temperature system was installed and fully tested, the reactor was returned to power. All systems and associated parameters continue to indicate normal and perform as expected.
If you have any comments or questions, please feel free to contact me at 509-335-0172.
Sincerely, Dr. Donald Wall Director, WSUNRC Cc: Marvin Mendonca, Project Manager
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 PROPOSEDCHANGE DOES NOT INVOL VE 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.
Tablel. 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 modem 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 Safety Channels Safety Channel Function Tech. Spec. Current Proposed Requirements Number Change Steady State Mode Fuel temperature SCRAM at 5000(2 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 5000C 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 PROPOSEDCHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE FREQUENCY OR OCCURENCEOFANACCIDENTPREVIOUSLYEVALUA TED 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. (Fuel failure in air.)
Several factors affect the possibility of fuel failure, including the possibility of instrument failure. However, as the instruments to be replaced are exceedingly old, and often unreliable. 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 has nothing to do with console controls or fuel temperature indication.
- d. Accidental Pulse rod ejection.
The upgrade of the fuel temperature system has no bearing or interconnection to 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 Since the new indication will be directly replace the current indication, and will be hooked up to the SCRAM chain appropriately, there will be no problem meeting these criteria.
- 3. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THANA MINIMAL INCREASE IN THE LIKELIHOOD OCCURRENCE OFA MALFUNCTION OFA STRUCTURE, SYSTEM, OR COMPONENT (SSC)IMPORTANT TO SAFETY PREVIOUSLY E VALUA TED IN THE FSAR (As UPDATED).
Since fuel temperature indication is an SSC important to safety, this question must be addressed. However, as noted above, the original indication has become unreliable, and prone to spurious SCRAMs. The installation of the new indication system will increase safety and reliability considerably.
- 4. THE PROPOSED CHANGE SHALL NOT RESULT IN MORE THAN A MINIMAL INCREASE IN THE CONSEQUANCES OFAN ACCIDENT PREVIOUSLY EVALUATED IN THE FSAR(AS UPDATED).
The results of the accidents in question are outlined in the appendix A to the SAR.
Instrumentation changes in the console should have no effect on the consequences of any of these postulated accidents.
- 5. THE PROPOSEDCHANGE SHALL NOT CREA TE A POSSIBILITY FOR AN ACCIDENT OFA DIFFERENTTYPE THAN ANY PREVIOUSLY EVALUA TED IN THE FINAL SAFETY ANALIYSIS 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 result in the same problem as a failure of current instrumentation,namely incorrect fuel temperature indication. These problems have already been evaluated for consequences, and no additional problem/consequence scenarios should occur with newer instrumentation.
- 7. THE PROPOSED CHANGE SHALL NOT RESULT INA 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 temperatur--imit, 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.
Should the channel fail, the fuel temperature limit could, theoretically, be exceeded. However, this possibility exists with current instrumentation, and there should be no increase in this possibility.
- 8. THE PROPOSED CHANGE WILL NOT RESULT IN DEPARTURE FROMA METHOD OF EVALUATION DESCRIBEDIN THE FSAR (As UPDATED) USED IN ESTABLISHING THE DESIGN BASES OR IN THE SAFETY ANALYSIS.
No such change will occur.
- A C. DETERMINATION OF RSC REVIEW NECESSITY Under our current procedures, any change to the facility as described in the SAR needs to be approved by the Reactor Safeguards Committee. As instrumentation is described in the SAR, this change must be approved by the RSC. New procedures will be developed for the new equipment following installation.
D. RECOMMENDATION This proposed change, in my opinion, 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 comm--please feel free to contact me.
RSC Approval: il Eric Corwin, Reactor Sup rvi/or Dr. Donald Wall, Director