ML20076L579
| ML20076L579 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/25/1994 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML20076L577 | List: |
| References | |
| NUDOCS 9411030345 | |
| Download: ML20076L579 (6) | |
Text
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CONTAINMENT SYSTEMS ELECTRIC HYDROGEN RECOMBINERS LlMITING CONDITION FOR OPERATION 3.6.4.2 Two sepam e and independent containment hydrogen mcombiner systems (shared with Unit 2) shall be OPERABLE.
APPLICABI'LITY:
MODES I and 2.
ACTION:
With one hydrogen recombiner system inoperable, restore the inoperable system to l
a.
OPERABLE status within 30 days or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
b.
The provisions of Specification 3.0.4 are not applicable.
l SURVEILLANCE REQUIREMENTS J
4.6.4.2 Each hydrogen recombiner system shall be demonstrated OPERABLE once per 18 -
l months by:
l Verifying, during a recombiner system functional test, that the minimum heater a.
sheath temperature increases to greater than or equal to 700 F within 90 minutes and is maintained for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and that each hydmgcn recombiner purge blower operates for at least 15 minutes.
b.
Verifying, during a recombiner system functional test using containment atmospheric air at a flow rate of gmater than or equal to 50 scfm, that the heater temperature increases to greater than or equal to 1100 F within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and is l
maintained for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Verifying the integrity of all heater electrical circuits by performing a resistance to l
c.
ground test following the above required functional test. The resistance to ground for any heater phase shall be greater than or equal to 10,000 ohms.
d.
Verifying, through a visual examination, that there is no evidence of abnormal conditions within the recombiner enclosure (i.e., loose wiring or structural connections, deposits of foreign materials, etc.).
e.
Performing a CHANNEL CALIBRATION cf all recombiner instmmentation and l
control circuits.
l NORTH ANNA - UNIT 1 3/4 6-34 Amendment No.
9411030345 941025 PDR ADOCK 05000338 P
CONTAINMENT SYSTEMS ELECTRIC HYDROGEN RECOMBINERS LIMITING CONDITION FOR OPERATION 3.6.4.2 Two separate and independent containment hydrogen recombiner systems (shared with Unit 1) shall be OPERABLE.
APPLICABILITY:
MODES I ar.d 2.
ACTION:
a.
With one hydrogen recombiner system inoperable, restore the inoperable system to OPERABLE status within 30 days or be in at least HOT STANDBY within the next
)
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
b.
The provisions of Specification 3.0.4 are not applicable.
SURVEILLANCE REQUIREMENTS 4.6.4.2 Each hydrogen recombiner system shall be demonstrated OPERABLE once per 18 months by:
a.
Verifying, during a recombiner system functional test, that the minimum heater sheath temperature increases to greater than or equal to 700 F within 90 minutes and is maintained for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and that each hydrogen recombiner purge l
blower operates for at least 15 minutes.
b.
Verifying, during a recombiner system functional test using containment l
atmospheric air at a flow rate of greater than or equal to 50 scfm, that the heater temperature increases to greater than or equal to 1100 F within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and is maintained for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Verifying the integrity of all heater electrical circuits by performing a resistance to l
c.
ground test following the above required functional test. The resistance to ground for any heater phase shall be greater than or equal to 10,000 ohms.
d.
Verifying, through a visual examination, that there is no evidence of abnormal l
conditions within the recombiner enclosure (i.e., loose wiring or structural connections, deposits of foreign materials, etc.).
l l
e.
Performing a CHANNEL CALIBRATION of all recombiner instrumentation and l
control circuits.
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l NORTH ANNA - UNIT 2 3/4 6-33 Amendment No.
l
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Significant Hazards Consideration
SIGNIFICANT HAZARDS CONSIDERATION The NRC has completed a comprehensive examination of surveillance requirements in Technical Specifications that require testing at power.
The evaluation is documented in NUREG-1366, " Improvements to Technical Specification Surveillance Requirements," dated December 1992. The NRC staff found, that while the majority of testing at power is important, safety can be improved, equipment degradation decreased, and an unnecessary burden on personnel resources eliminated by reducing the amcunt of testing at power that is required by Technical Specifications.
Based on the results of the evaluations documented in NUREG-1366, the NRC issued Generic Letter 93-05, "Line-Item Technical Specifications Improvements to Reduce Surveillance Requirements for Testing During Power Operation," dated September 27, 1993.
The Hydrogen Recombiner System removes the hydrogen gasses that accumulate in the containment atmosphere following a design-basis loss-of-coolant accident. Using the guidelines provided by Generic Letter 93-05, item 8.5 and NUREG-1366, we are requesting a change to the functional surveillance testing frequency for the hydrogen recombiners from once per 6 months to once per 18 months. These changes in the surveillance requirements do not affect plant or Hydrogen Recombiner System operations. In addition, several other changes are being requested for clarity and consistency between Unit 1 and Unit 2 Technical Specifications.
Technical Specification Surveillance Requirement 4.6.4.2.a states in part that "... each purge blower operates for 15 minutes." The North Anna units are equipped with two different types of " purge blowers." One type of purge blowers are an integral part of the Hydrogen Recombiner System. These hydrogen recombiner purge blowers are capable of exhausting containment gasses directly to atmosphere even with the recombiner incapable of removing hydrogen gas. The second type of purge blowers are the containment purge blowers which exhaust directly from the containment to atmosphere and are not associated with the hydrogen recombiners. Surveillance Requirement 4.6.4.2.a will be modified to state that the purge blowers are being referred to in this surveillance requirement are the hydrogen recombiner purge blowers.
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l Virginia Electric and Power Company has reviewed the proposed changes against the l
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criteria of 10 CFR 50.92 and has concluded that the changes as proposed do not pose a significant hazards consideration. Specifically, operation of North Anna Power Station in accordance with the proposed Technical Specifications changes will not:
- 1. Involve a significant increase in the probability or consequences of an accident previously evaluated.
Testing of the Hydrogen Recombiner System once per 18 months will continue l
to assure that the Hydrogen Recombiner System will be capable of performing its intended functions. The containment purge blowers are not part of the Hydrogen Recombiner System and are not assumed to function during accident conditions. Therefore, these changes to the Hydrogen Recombiner System j
Technical Specifications do not affect the probability or consequences of any previously analyzed accident.
l
- 2. Create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed Technical Specification changes do not involve any physical modification of the plant or result in a change in a method of operation. Testing the Hydrogen Recombiner System once per 18 months will continue to assure that the Hydrogen Recombiner System will be capable of performing its intended function. Therefore, a new or different type of accident is not made possible.
- 3. Involve a significant reduction in a margin of safety.
The proposed Technical Specification changes do not affect any safety limits or limiting safety system settings. System operating parameters are unaffected.
The availability of equipment required to mitigate or assess the consequence of an accident is not reduced. The containment purge blowers are not part of the Hydogen Recombiner System and are not assumed to function during accident conditions. Testing of the Hydrogen Recombiner System once per 18 months will continue to assure that the Hydrogen Recombiner System will be capable of performing its intended functions. Safety margins are, therefore, not decreased.
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Virginia Electric and Power Company concludes that the activities associated with these proposed Technical Specification changes satisfy the no significant hraards consideration of the criteria of 10 CFR 50.92 and, accordingly, a no significant hazards consideration finding is justified.
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