ML20247H875
| ML20247H875 | |
| Person / Time | |
|---|---|
| Site: | Washington State University |
| Issue date: | 06/30/1989 |
| From: | WASHINGTON STATE UNIV., PULLMAN, WA |
| To: | |
| Shared Package | |
| ML20247H872 | List: |
| References | |
| NUDOCS 8909200132 | |
| Download: ML20247H875 (3) | |
Text
_,.
NK, y,
~k AMENDMENT TO THE' ANNUAL' REPORT ON.THE OPERATION OF Q
THE WASHINGTON STATE UNIVERSITY TRIGA REACTOR u
-Fa'cility License R-76 for the Reporting Period of July _1,1988 to June 30,<1989
~
This amendment to W.S.U.'l Annual' Report contains some corrections and missing data that.was not available at the time the Annual Report was prepared.
The' corrections'and completed-data are as follows:
Pace 1. Section A.
Item 2. Narrative'Summarv of the Year's Operations.
2.
There were no changes in the desi n or operating procedures that 5
- r. elated to reactor safety during;the reporting period. However, there,was a change in the performance characteristics and is as follows; l
In April-1989, Bill Wilson _re-evaluated the pulsing limit for the W.S.U. reactor for Core 32-A.
Based on his re-evaluation, it was determined the Pulsing' Limit given in the Technical Specifications, Section 3.3 should be changed from a maximum reactivity limit of
$2.50 to $2.20. Administrative 1y, the pulsing reactivity limit has been set _at $2.00 since 1976. A complete report of the re-evaluation.
of the pulsing limit is forth coming.
-1 Pace 5.
Section G.
Table VI. Averace Ouarterly Reactor and Experimenter Staff Exposure.
June's-film badge results were not available from the vendor'at the time the' Annual Report was prepared. Table VI below'now contains the missing film
- badge.results
TABLE VI AveraSe Quarterly Reactor and Experimenter Staff Exposure l
(in millirem)
Jul-Aug-Sep Oct-Nov-Dec Jan-Feb-Mar Apr-May-Jun 30 57 10 16 8909200132 890912 PDR ADOCK 05000027 R
PDC e
---_------_----______---_-__-__-----_--___-___._._____-___--___-.-__-----__-------------.----------a---,----
I i
-)
2 i
Pace 6.Section I'. Environment 1 Monitorine Program.
~
Due to an administx. -- delay in renewing the contract with the vendor who supplies the TLD dosimeters, new ov 1 eters have not yet been received.
The
. contract renewal delay has been correcteu c4 new dosimeters are presently being shipped. When they arrive, the dosimeters presentif placed about the facility will be changed and processed and the results evaluaten.
A F
g 3.3 Pulse Mede Crernien Acelicabilitv:
This specification applies to the peak fuel p
temperature in the reactor as a result of a pulse insertion of I
l reactivity.
1 I
obdective:
The objective is to ensure that fuel element damage does not occur in any fuel rod during pulsing.
Specification:, The maximum reactivity inserted during pulse l
mcde operation shall be such that the "veak fuel ta=cerature in any fuel red in the c=re dces not exceed 830~C.
The maximum safe allevable reactivity insertien shall be calculated annually for an existing c=re and prior to pulsing a new or mcdified c=re arrangement.
Basis:
TRIGA fuel is fabricated with a nominal hydr gen to circonium radio of 1.6 for FL ? fuel and 1. 65. f=r Standard.
This yields delta phase :ir==nium hydride which has a high creep strength and undergoes no phase changes at ta=peratures over 1000*C, Ecwever, after extensive steady state operation at 1 Mw, the hydrogen will redistribute due
= migration from the central hign temperature regions of the fuel to the eccler outer regienu.
When the fuel is pulsed, the instantaneous te=perature distribution is such that the highest values cccur at the surface of the element and the lcwest values cc=ur at the center.
The higner temperatures in the cuter regions cccur in fuel with a hydr: gen to :ircenium ratio that has new substantially increased abcve the ncminal value.
This pr: duces hydr: gen gas pressures c=nsiderably in excess of that expected for OrH, 6
If the pulse inser-ion is such that the temperature of t.e fuel exceeds 87400, then the pressure will be sufficient to cause expansion of micr:sc pic holes in the fuel that grew larger with each pulse.
The expansion of the fuel stresses and dist=rts the fuel red material which, in
- turn, can cause overall swelling and dist rti n of the cladding and entire fuel red.
The pulsing limit of 830 0 is 0
obtained by examining the equilibrium hydr gen pressure of circenium hydride as a function of tercerature.
The decrease in temperature fr0m 874 C to 830 C reduces hydrogen pressure 0
by a factor of two, which pr=vides an acceptable safety facter.
This phencmenon does not alter the steady state safety limit since the t:tal hydrogen in a fuel element dces not change.
Thus, the pressure exerted on the clad will not be significantly affected by the distribution of hydrogen within the element.
I n
- - _ _.