ML20035E763
| ML20035E763 | |
| Person / Time | |
|---|---|
| Site: | University of Michigan |
| Issue date: | 04/15/1993 |
| From: | MICHIGAN, UNIV. OF, ANN ARBOR, MI |
| To: | |
| Shared Package | |
| ML20035E761 | List: |
| References | |
| NUDOCS 9304190211 | |
| Download: ML20035E763 (2) | |
Text
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OPERATING LICENSE AND TECHNICAL SPECIFICATIONS Ford Nuclear Reactor Docket 50-2, License R-28 Amendment 38:100792 I
3.0 LIMITING CONDITIONS FOR OPERATION 4
e 3.1 Reactivity Limits f
Applicability:
This specification applies to the reactivity of the reactor core and to the reactivity worths of control rods and experiments.
When the reactor is operated with the heavy water reflector tank in place, the limits will not include the static reactivity worth of the tank.
Objective:
To assure that the reactor can be controlled and shutdown at all times and that the safety limits will l
not be exceeded.
l Specification:
l 1.
The shutdown margin relative to the cold, xenon free, critical condition shall be at least.025 delta K/K with all three shim safety-rods fully inserted and the regulating rod fully withdrawn and 0.0045 delta K/K with the most reactive shim-safety rod and the regulating rod fully withdrawn, except during the 38 process of verifying shutdown margin.
2.
The overall core excess reactivity including moveable experiments shall not exceed 0.0436 j35 delta K/K.
3.
The reactivity worth of experiments shall be limited i
as follows, except during the process of verifying 38 experiment reactivity:
I Maximum Experiment Feactivity Worth I
l Individual Moveable 0.0012 delta K/K a
Individual Secured 0.012 delta K/K i
Total Moveable and Secured 0.012 delta K/K i
4.
The reactor shall be suberitical by at least 0.025 delta K/K during fuel movements to and 38 from the reactor core.
5.
The reactor shall be suberitical by at least 38 l
0.10 delta K/K before shim-safety rods are l
removed from the core.
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OPERATING LICENSE AND TECHNICAL SPECIFICATIONS Ford Nuclear Reactor-Docket 50-2, License R-28 i
2 Amendment 38:100792 j
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6.
The reactor shall be suberitical by at least 38 0.10 delta K/K whenever heavy water movements j
7 e
that can result in positive reactivity insertions are undertaken.
l I
l i
7.
TheLreactivity worth of the regulating' rod shall'not i
exceed 0.006 delta K/K.
J 8.
Experiments that could increase reactivity by flooding, shall not remain'in or adjacent to the l
core unless the shutdown margin required'in j
~
1 Specification 3.1.1 would be' satisfied-after i
flooding.
Bases:
t The shutdown margin required by Specification 3.1.1 l
assures that the reactor can be shutdown from any operating condition and will remain suberitical after-cooldown and. xenon decay even if the rod of the j
highest reactivity worth should be in the. fully withdrawn position.
l 1
A Specification 3.1.2 limits the allowable excess j
reactivity to the value necessary to overcome the j
combined negative reactivity effects of: (1) an increase in primary coolant temperature from 90'F to 116 F; (2) fission product xenon and samarium buildup in a i
clean core; (3) power defect due to increasing from a zero power, ' cold core to a 2 Mw, hot core; (4) fuel burnup during sustained operation for 30 days; and I
(5) moveable experiments.
1 1
Specification 3.1.3 limits ~the individual reactivity I
worth of moveable experiments to values that will not l38 produce a stable period of less than 30 seconds and
.L which can be compensated for by the action of the control
]
and safety systems without exceeding any safety limits.
Specification 3.1.3 limits the reactivity worth of 38 secured and total experiments to values of reactivity which, if introduced as positive step-changes, will not cause fuel melting.
Specifications 3.1.4 and 3.1.5 provide assurance that the core will remain suberitical during fuel movements 38 to and from the core and aring shim-safety rod maintenance or inspection.
The largest positive reactivity increase that can be l33 produced by replacing light water with heavy water in the heavy water reflector tank is 0.04 delta K/K.
Maintaining the core'suberitical by at least 0.10 38 delta K/K.in' Specification 3.1.6 during heavy water 4
transfers provides adequate margin to assure that Page 11
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