ML20127M436
| ML20127M436 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/15/1985 |
| From: | NORTHEAST NUCLEAR ENERGY CO. |
| To: | |
| Shared Package | |
| ML20127M426 | List: |
| References | |
| NUDOCS 8505230270 | |
| Download: ML20127M436 (4) | |
Text
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Docket No. 50-245~
- Attachment 1 Millstone Nuclear Power Station, Unit No.1 Proposed Revisions to Technical Specifications Containment Systems O
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d P
1 1
LIMITIM Co WITION FOR OPERATION SURVEILLANCE REQUIREMENT' i
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j 3.
Differential pressure may be less than 1.0 psid for a period not to exceed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> for purposes of conducting a drywell entry.
b.
Drywell to torus differential pressure instrumentation shall be calibrated once
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l 4.
If the provisions of (1) and (2) above cannot be met, the differential pressure shall be restored within the subsequent six (6) c.
The drywell to torus differential pressure hour period or the provisions of 3.7.A.7 instrumentation shall be calibrated once per shall apply.
six months if both systems are operable.
b.
At least one (1) drywell to torus differential pressure monitoring system shall be operable whenever primary containment is required, except as specified in 3.7.A.2.c.
c.
If the drywell to torus differential pressure monitoring system is disabled and cannot be restored in six (6) hours an orderly shutdown shall be initiated and the reactor shall be in cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> unless the dif.ferential pressure monitoring systen is made operable.
Amendment No. 51 3/4 7-4 m
LIMITING CONDITI'ON FOR OPERATION SURVEILLANCE REQUIREMENT' 6.
Drygen concentration:
6.
Oxygen concentration:
a.
After completion of the startup test Whenever inerting is required, the progree and demonstration of plant primary containment oxygen concentra-electrical output, the primary contain-tion shall be measured and recorded ment atmosphere shall be reduced to on a weekly basis.
less than 4% oxygen with nitrogen gas whenever the reactor coolant pressure is greater than 90 psig and during reactor power operation except as I
specified in 3.7.A.6.b er 3.7.A.6c.
b.
Within the 24-hour period subsequent to placing the reactor in the Run made following a shutdown, the containment atmospbere oxygen concentration shall i
I be reduced to less than 4% by volume and maintained in this condition.
Deinerting may commence 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to a shutdown.
c.
Oxygen concentration may be greater then 4% by volume for a period not to exceed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> for purposes of conducting a l
drywell entry.
7.
If the specifications of 3.7.A cannot be met, initiate an orderly shutdown and have the reactor in a cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Amendmer*No.,)6.j)f.JSi 3/4 7-12
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_ 3 -y 7 b
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6.
OxYaen Concentration
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The relatively small containment volume inherent in the GE-BWR pressure. suppression containment and:the large amount of zirconium in the core are such that the occurrence of a very limited (a percent of so) reaction of the zirconium and steam'during a loss of coolant accident would lead to the liberation of-l sufficient hydrogen to result in'a flammable concentration in the containment. Subsequent ignition of the i
hydrogen if it is present in sufficient quantities to result in excessively rapid recombination, could result in a loss of containment intergrity.-
I The 4% oxygen concentration minimizes the possibility of hydrogen' combustion following a loss of coolant accident. Significant quantities of hydrogen could be generated if the core cooling systems did not i
sufficiently cool.the core.
J The occurrence of primary system leakage following a major refueling outage or other scheduled shutdown is more probable than the occurrence of the loss of coolant accident upon which the specified oxygen concentra-l tion limit is based. Permitting access to the drywell for leak inspections during a startup is judged prudent in terms of the added plant safety _without significantly reducing the margin of safety. Thus to j
preclude the possibility of starting the reactor and operating for extended periods of time with significant
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leaks in the primary system, leak inspections are scheduled during startup periods, when the primary system is at or near rated operating temperature and pressure. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period to provide inerting is judged to be sufficient to perform the leak inspection and establish the required oxygen concentration. The primary containment is normally slightly pressurized during periods of reactor operation assuring no air in-leakage through the primary containment. However, at least once a week, the oxygen concentration will be determined as added assurance.
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B.
Standby Gas Treatment Systems and j
C.
Secondary Containment The secondary containment is designed to minimize any ground level release of radioactive materials which might-result from a serious accident. The reactor building provides secondary containment during reactor operation, l
when the drywell is sealed and in service; the reactor building provides primary containment when the reactor is chutdown and the drywell is open, as during refueling. Because the secondary containment is an integral part of 1
the complete containment system, secondary containment is required at all-times that primary containment is i
required.
l Amendment 1 B 3/4 7-5 i
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