ML20141A017
| ML20141A017 | |
| Person / Time | |
|---|---|
| Site: | 05000231 |
| Issue date: | 08/06/1971 |
| From: | GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20140G249 | List:
|
| References | |
| FOIA-97-34 NUDOCS 9705140138 | |
| Download: ML20141A017 (5) | |
Text
! , * .-
.s j g-
- f. :
- y. ]
.. l l .
I a
. 1
(. ~g I
Regulatory File dy.-
1 I
ATTACHMENT A w .4* m P- 6-7/ ;
)
l l
1 REVISED PAGES FOR THE e
t
- o. .
[. SEFOR TECHNICAL SPECIFICATIONS I
i l
i i
. i l
PROPOSED CHANGE NO. 6 l
l August 5, 1971 1
l i
i l
i i
l l
l i
+
l
VARADY97-34 e. w we PDR
p
'}% y.
, e B. General
- 1. An, excursion test shall be performed with the FRED only if the analysis of previous operating data indicates that the sodium-p in Doppler coefficient (T f) is negative and has a magnitude; equal to or greater than 0.005.
- 2. - The time required for the poison slug to travel the first 20 ,
inches af ter lif t-off shall be equal to or greater than 0.097 second. -
- 3. The main primary coolant flow rate shall be at least 4000 GPM
. when the poison slug is ejected from the core.
- 4. The scram system may be modified in accordance with the des-cription in Supplement 17 to the FDSAR, page G-1, to provide an additional 400 millisecond delay between a scred signal and the point in time when the reflector segments start to move.
- 5. Whenever a poison slug worth more than 1$ is lowered into
. the core by means of the FRED, containment integrity shall be maintained and the isolation valves on the outer containment ventilation lines shall be closed.
- 6. If fuel rod inspections called for in Section 4.3 indicate that the limits of fuel def ects (as defined in Section 3.3.K.2 and 3) i are being approached, succeeding excursion tests shall be limited to power excursions below that at which such behavior was observed. ;
- 7. The initial reactor power level for excursion tests shall be equal to or greater than 0.1 MW.
- 8. System checkout of the FRED components may be performed at power levels less than 0.1 MW, provided the initial position of the poison slug is more than 20 inches above the core mid-plane.
- 9. The core coolant inlet temperature shall not be below 700*F at the start of each excursion test.
- 10. Excursion tests shall not be conducted if there is evidence that the core contains defective fuel rods. .
Proposed Change No. 6 August 5, 1971 3.12-2
.m
() ,b. .
. . U 4
-Bases
, ' The experimental program with FRED is graded so that small transients t
precedelarder' transients. The information from the small transients ,
l will be used (1)-to evaluate the performance of the reactor, (2) to I
l l
' compare the performance with predicted behavior, and (3) to predict performance of the reactor for the larger prompt critical transients.
The characterization of the tests into the categories of- (1), (2) and -
(3) above is self-explanatory.. The maximum power levels indicated in j l
mach case are to assure that. the safety , limits as given in Section 2.1 )1 will not be violated and are in accordance with Figure 2.1-1 and the explanation in Section 2.1. The limits given in this specification 1 1
also assure that the maximum energy addition to the core during a l l
planned transient does not exceed that calculated for the Maximum !
Planned Transient.(10) This in turn assures that the maximum con- '
l- \
l sequence of inadvertently running 'a transient with a defective (sodium-
, logged) fuel rod in the core would be limited. to deformations corresponding I to about 0.6% strain of the cladding of the defective fuel rod.III)
This amount of strain is only 4% of the minimum ductility of the SEFOR cladding at the end of the three-year experimental program.(1 )
The value of the Doppler coefficient for SEFOR Core I with sodium in the dk core 1,s estimated to be Tg = -0.0085. This value was verified experi-mentally by means of Doppler measurements on the SEFOR mockup in the ZPR-III Critical Facility. From.further measurements on this mockup, it was established that the Doppler coefficient with sodium out is dk 17.5% lower than the value with sodium in, or Tg = -0.0070 for SEFOR Core I with sodium out.
The safety analysis of the MHA for SEFOR was based on a sodium-out dk Doppler coefficient of Tg = -0.004, which corresponds to a sodium-in Doppler coefficient' (T ) of -0.005.( ) The demonstration of a negative 3.12-3 i l- Propose Change No. 6 l
! August 5, 1971
,.,,v . - .- . .
._ , . .. ~ . - .. . _ . . - - - . . .. - .=.. ._
Q.
n v
l 1
, , Doppler coefficient with a magnitude equal to or great:er than 0.005 f
l during the approach to maximum power will verify predictions of this . 1 coefficient' based on the ZPR-III measurements and will provide the
. basis for. safe performance of prompt critical tests in SEFOR. ,
s The total reactivity worth of each poison slug used in 'the FRED will I be known and the value will be checked before each transient test. I The maximum reactivity insertion rate will be limited to less than l 1 20$ per second by limiting the reactivity worth of the slug to 1.3$
l and by limiting the minimum allowable time for the slug to travel the j first 20 inches to 0.097 second.(3) This time will be measured by
, l means of the lif t-off switch and a proximity switch which marks 20
]
l inches of travel by the poison slug. The safety of the plant has been assessed for a maximum r,ste of 50$ per second with a sodium-out l Doppler coefficient (T >'of -0.004.(4) l .
i l
l l
l.
j l
l I
L .
i i
l t
t t
i
! 3.12-3 A Proposed Change No. 6
. August 5, 1971 I
- v. o ct:rting from initici powsr 1Gvalo co low as 0.1 MWe io still wall below the safety limit.
Initial checkout tests of the FRED after it is installed on the reactor I ' head will be performed with the reactor either sub-critical or at low i power level (less ,than 0.1 MWt). The FRED will have a negligible effect on reactivity when it is in a position more than 20 inches above the core midplane.
The minimum limit of 700*F on the core coolant inlet temperature is to assure that the total reactivity of the core is maintained at the equivalent of 50c excess at 20 MW conditions.('} At lower temperatures, the excess core reactivity would be higher. The 504 excess limit assures that the Maximum Planned Transient will not be initiated from a power ,
level in excess of 11 MWt, and also limits the final reactor power if the reactor does not scram and the FRED slug remains out of the core following any excursion test. t References (1) SEFOR FDSAR, Appendix B, Section B.5, p. B-3.
(2) SEFOR FDSAR, Section 16.4.2.6.1.1, p. 16-28. .
(3) Proposed Change No. 6 for the Southwest Experimental Fast Oxide Reactor, August 5, 1971. .
(4) SEFOR FDSAR, Volume II, Section 16.2.7 (5) SEFOR FDSAR, Volume II, Section 16.2.7, p. 16-10.
(6) SEFOR FDSAR, Supplement 17, p. G-1.
(7) SEFOR FDSAR, Supplement 3, Section 5.1.3.
(8) SEFOR FDSAR, Supplement 19, p. 57.
(9) SEFOR FDSAR, Volume II, Section 12.3.6, pp. 12-15, 16.
(10) , SEFOR FDSAR, Supplement 10, page 1-48 (11) Additional Information Regarding Sodium Logging of SEFOR Fuel Rods, February 1, 1971. ,
(12) S EFOR FDSAR, Supplement 21, page 4.
3 .1 '.-3 Proposed Change No. 6 .
August 5, 1971
__ _