ML20033F302
| ML20033F302 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/02/1990 |
| From: | Black S Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20033F303 | List: |
| References | |
| NUDOCS 9003190342 | |
| Download: ML20033F302 (17) | |
Text
_.
t I'
. [se -e n,*'c, e
UNITED ST ATEs i
I-NUCLEAR REGULATORY COMMISSION 6
j wAsmNcTow. o c. 20sss s,,,
,,,i x
....+
i TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-327 L
SEQUOYAH NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE I
l Amendment No.131 License No. DPR-77' l
L 1.
The Nuclear Regulatory Commission (the Comission) has found that:
A.
The application for amendment by Tennessee Valley Authority (the licensee) dated January 12, 1990, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act),
I and the Comission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (1) that the activities authorized by this amendment can be conducted without endangering the health and I
safety of the public, and (ii) that such activities will be
[
conducted in compliance with the Comission's regulations; D.
The issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public; and-E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
L i
p 31 g y [@@@
7 P
{
2.
Accordingly, the license'is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and paragraph 2.C.(2) of facility Operating License No. DPR-79 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised-through Amendment No.131, are hereby incorporated in the license.
The licensee shall operate the facility in accordance with the Technical Specifications, 3.
This license amendment is effective as of its date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
.k F1nt-Su anne lack Assistant Director or Projects TVA Projects Division Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance: March 2, 1990
.s ATTACHMENT TO LICENSE AMENDMENT NO. 131 FACILITY OPERATING LICENSE NO. DPR-77 DOCKET NO. 50-327 Revise the Appendix A Technical Specifications by removing the pages identified below and inserting the enclosed pages. The revised pages are identified by the captioned amensient number and contain marginal lines indicating the area of change.
REMOVE INSERT 3/4 6-26 3/4 6-26 3/4 6-27 3/4 6-27 3/4 6-29 3/4 6-29 3/4 6-30 3/4 6-30 B 3/4 6-4 B 3/4 6-4
r' CON 1AINMENT SYSTEMS 3/4.6.5 ICE CONDENSER ICE BED LIMITING CONDITION FOR OPERATION 3.6.5.1.
The ice bed shall be OPERABLE with:
a.
The stored ice having a boron concentration of at least 1800 ppm boron as sodium tetraborate and a pH of 9.0 to 9.5, b.
Flow channels through the ice condenser, c.
A maximum ice bed temperature of less than or equal 27'F, d.
A total ice weight of at least 2,245,320 pounds at a 95% level of confidence, and e.
1944 ice baskets.
APPLICABILITY:
MODES 1, 2, 3 and 4.
ACTION:
With the ice bed inoperable, restore the ice bed to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.5.1 The ice condenser shall be determined OPERABLE:
a.
At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by using the ice bed temperature monitoring system to verify that the maximum ice bed temperature is less than or equal to 27 F.
b.
At least once per 12 months by:
1.
Chemical analyses which verify that at least 9 representative samples of stored ice have a boron concentration of at least 1800 ppm as sodium tetraborate and a pH of 9.0 to 9.5 ct 20 C.
SEQUOYAH - UNIT 1 3/4 6-26 Amendment No. 4, 126, 131
CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 2.
Verifying, by' visual inspection of a representative random l
sample of at least 54 flow passages (33 percent) per ice condenser bay, that the accumulation of frost or ice on flow passages between ice baskets, past lattice frames, through the intermediate and top deck floor grating, or past the lower inlet plenum support structures and turning vanes is less than or equal to 15 percent blockage of the total flow area in each bay, with a 95 percent level of confidence.
If the summation of blockage from the sample fails to meet the acceptance criteria, then 100 percent of the passages of that bay shall be inspected.
If the 100 percent inspection fails to meet the acceptance criteria, then the flow passages shall be cleaned to meet the acceptance criteria.
Each flow passage that is cleaned will be reinspected.
Any inaccessible flow passage that is not inspected will be considered blocked, c.
At least once per 40 months by lifting and visually inspecting the accessible portions of at least two ice baskets from each 1/3 of the ice condenser and verifying that the ice baskets are free of detrimental-structural wear,-cracks, corrosion or other damage.
The ice baskets shall be raised at least 10 feet for this inspection, d.
At least once per 18 months by:
Weighing a representative sample of at least 144 ice baskets and verifying that each basket contains at least 1155 lbs of l
ice.
The representative sample shall include 6 baskets from each of the 24 ice condenser bays and shall be constituted of one basket each from Radial Rows 1, 2, 4, 6, 8 and 9 (or from the same row of an adjacent bay if a basket from a designated row cannot be obtained for weigh.ing) within each bay.
If any basket is found to contain less than 1155 pounds of ice, a l
representative sample of 20 additional baskets from the same bay shall be weighed.
The minimum average weight of ice from the 20 additional baskets and the discrepant basket shall not be less than 1155 pounds / basket at a 95% level of confidence.
l The ice condenser shall also be subdivided into 3 groups of baskets, as follows:
Group 1 - bays 1 through 8, Group 2 -
bays 9 through 16, and Group 3 - bays 17 through 24.
The minimum average ice weight of the sample baskets from Radial Rows 1, 2, 4, 6, 8 and 9 in each group shall not be less than 1155 pounds / basket at a 95% level of confidence.
l The minimum total ice condenser ice weight at a 95% level of confidence shall be calculated using all ice basket weights determined during this weighing program and shall not be less than 2,245,320 pounds.
SEQUOYAH - UNIT 1 3/4 6-27 Amendment No. 4, 98, 131
t
.c L
CONTAINMENT SYSTEMS ICE CONDENSER DOORS LIMITING CONDITION FOR OPERATION 3.6.5.3 The ice condenser inlet doors, intermediate deck doors, and top deck doors shall be closed and OPERABLE.
APPLICABILITY:
MODES 1, 2, 3 and 4.
ACTION:
With one or more ice condenser doors open or otherwise inoperable, POWER OPERATION may continue for up to 14 days provided the ice bed temperature is monitored at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the maximum ice bed temperature is maintained less than or equal to 27'F; otherwise, restore the doors to their closed positions or OPERABLE status (as applicable) within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 /> and in COLD SHUT 00WN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.5.3.1 Inlet Doors - Ice condenser inlet doors shall be:
a.
Continuously monitored and determined closed by the inlet door position monitoring system, and b.
Demonstrated OPERABLE at least once per 18 months by:
1.
Verifying that the torque required to initially open each door is less than or equal to 675 inch pounds.
2.
Verifying that opening of each door is not impaired by ice,
-frost or debris.
3.
. Verifying that the torque required to open each door is less l
than 195 inch pounds when the door is 40 degrees open.
This torque is defined as the " door opening torque" and is equal-to the nominal door torque plus a frictional torque component.
l SEQUOYAH - UNIT 1 3/4 6-29 Amendment No. 25, 131
.R CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4 Verifying that the torque required to keep each door from closing
{
is greater than 78 inch pounds when the door is 40 degrees open.
This torque is defined as the " door closing torque" and is equal to the nominal door torque minus a frictional torque component.
5.
Calculation of the frictional torque of each door tested in-accordance with 3 and 4, above.
The calculated frictional torque-shall be less than or equal to 40 inch pounds.
4.6.5.3.2 Intermediate Deck Doors - Each ice condenser intermediate deck door shall be:
Verified closed and free of frost accumulation by a visual inspection a.
at least once per 7 days, and b.
Demonstrated OPERABLE at least once per 18 months by visually verifying no structural deterioration, by verifying free movement of the vent assemblies, and by ascertaining free movement when lifted with the applicable force shown below:
Door Lifting Force 0-1, 0-5 Less than or equal to 33 lbs.
0-2, 0-6 Less than or equal to 30 lbs.
0-3, 0-7 Less than or equal to 28 lbs.
0-4, 0-8 Less than or equal to 28 lbs.
4.6.5.3.3 Top Deck Doors - Each ice condenser top deck door shall be determined closed and OPERABLE at least once per 92 days by visually verifying; a.
That the doors are in place, and-b.
That no condensation, frost, or ice has formed on the doors or blankets which would restrict their lifting and opening if required.
l l
SEQUOYAH - UNIT l' 3/4 6-30 Amendment No. 25, 131
..a t
C'ONTAINMENT SYSTEMS BASES 3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions.
Either recombiner unit or the hydrogen mitigation system, consisting of 68 hydrogen ignitions per unit, is capable of controlling the expected hydrogen generation associated with 1) zirconium-t water reactions, 2) radiolytic decomposition of water and 3) corrosion of metals within containment. These hydrogen control systems are designed to mitigate the effects of an accident as described in Regulatory Guide 1.7,
" Control of Combustible Gas Concentrations in Containment Following a LOCA",
revision 2 dated November 1978.
The hydrogen mixing systems are provided to ensure adequate mixing of the containment atmosphere following a LOCA.
This mixing action will prevent localized accumulations of hydrogen from exceeding the flammable limit.
The operability of at least 66 of 68 ignitors in the hydrogen mitigation system will maintain an effective coverage throughout the containment.
This system of ignitors will initiate combustion of any significant amount of hydrogen released after a degraded core accident.
This system is to ensure burning in a controlled manner as the hydrogen is released instead of allowing it to be ignited at high concentrations by a random ignition source.
l l
3/4.6.5 ICE CONDENSER 1
The requirements associated with each of the components of the ice con-denser ensure that the overall system will be available to provide sufficient pressure suppression capability to limit the containment peak pressure tran-I sient to less than 12 psig during LOCA conditions.
l 3/4.6.5.1 ICE BE0 The OPERABILITY of the ice bed ensures that the required ice inventory lz will 1) be distributed evenly through the containment bays, 2) contain suffi-I cient boron to preclude dilution of the containment sump following the LOCA and 3) contain sufficient heat removal capability to condense the reactor l
system volume released during a LOCA.
These conditions are consistent with the assumptions used in the accident analyses.
i The minimum weight figure of 1155 pounds of ice per basket contains a 15%
l conservative allowance for ice loss through sublimation which is a factor of 15 higher than assumed for the ice condenser design.
The minimum weight figure of 2,245,320 pounds of ice also contains an additional 1% conservative allowance to account for systematic error in weighing instruments.
In the Amendment No. 4, 5, 131 SEQUOYAH - UNIT 1 B 3/4 6-4 Revised 08/18/87
?
I
?
ai s eu,s
[s It UNITED STATES j'
h _
NUCLE AR REGULATORY COMMISSION p,
WASHINGTON,0 C 20555 t
' ~x Y
J
....+
, TENNESSEE VALLEY AUTHORITY 00CKET NO. 50-328 SEQUOYAH NUCLEAR PLANT, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No.118 License No, DPR-79 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A, The application for amendment by Tennessee Valley Authority (the licensee) dated January 12, 1990, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act),
and the Commission's rules and regulations set forth in 10 CFR Chapter I; 1
l B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C,
There is reasonable assurance (1) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be L
-conducted in compliance with the Commission's regulations; p
H D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
L
--<c i.**
r 2
i 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and paragraph 2.C.(2) of facility Operating License No. OPR-77 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendices A and 3, as revised through Amendment No.118, are hereby incorporated in the license.
The licensee shall operate the facility in accordance with the Technical Specifications.
l.
3.
This license amenament is effective as of its date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION 1
u
- g4n, z A n,e Tack, Assistant Director for Projects TVA Projects Division Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance:
March 2, 1990
ATTACHMENT TO LICENSE AMENDMENT NO.118 FACILITY OPERATING LICENSE NO. DPR-79 DOCKET NO. $0-328 Revise the Appendix A Technical Specifications by removing the pages identified The revised pages are identified by below and inserting the enclosed pages.
the captioned amendment number and contain marginal lines indicating the area of change.
REMOVE INSERT 3/4 6-27 3/4 6-27 3/4 6-28 3/4 6-28 3/4 6-30 3/4 6-30 3/4 6-31 3/4 6-31 3/4 6-32 3/4 6-32*
B 3/4 6-4 3/4 6-4 I
l
a t
CONTAINMENT SYST[MS 3/4.6.5 ICE CONDENSER i
ICE BED LIMITING CONDITION FOR OPERATION 3.6.5.1 The ice bed shall be OPERABLE with:
a.
The stored ice having a boron concentration of at least 1800 ppm boron as sodium tetraborate and a pH of 9.0 to 9.5, I
b.
Flow channels through the ice condenser, c.
A maximum ice bed temperature of less than or equal to 27'F, d.
A total ice weight of at least 2,245,320 pound at a 95% level of confidence, and e.
1944 ice baskets.
APPLICABILITY: MODES 1, 2, 3 and 4.
ACTION:
With the ice bed inoperable, restore the ice bed to OPERABLE status within 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> 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 /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.5.1 The ice condenser shall be determined OPERABLE:
a.
At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by using the ice bed temperature monitoring system to verify that the maximum ice bed temperature is less than or equal to 27'F.
b.
At least once per 12 months by:
1s Chemical analyses which verify that at least 9 representative samples of stored ice have a boron concentration of at least 1800 ppm as sodium tetraborate and a pH of 9.0 to 9.5 at 20'C.
l l
l SEQUOYAH - UNIT 2 3/4 6-27 Amendment No. 80 118 Correction-Letter of-1-22-89,
r CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 2.
Verifying, by visual inspection of a representative random l
sample of at least 54 flow passages (33 percent) per ice condenser bay, that the accumulation of frost or ice on flow passages between ice baskets, past lattice frames, througn the intermediate and top deck floor grating, or past the lower inlet plenum support structures and turning vanes is less than or equal to 15-percent blockage of the tot (1 flow area in each bay, with a 95 percent level of confidence.
If the summation of blockage from the sample fails to meet the acceptance criteria, then 100 percent of the passages of that-bay shall be inspected.
If the 100 percent inspection fails to meet the acceptance criteria, then the flow passages shall be cleaned to meet the acceptance criteria.
Each flow passage that is cleaned will be reinspected.
Any inaccessible flow passage that is not inspected will be considered blocked, c.
At least once per 40 months by lifting and visually inspecting the accessible portions of at least two ice baskets from each 1/3 of the ice condenser and verifying that the ice baskets are free of detri-mental structural wear, cracks, corrosion or other damage.
The ice baskets shall be raised at least 10 feet for this inspection, d.
At least once per 18 months by:
Weighing a representative sample of at least 144 ice baskets and verifying that each basket contains at least 1155 lbs of l
ice.
The representative sample shall include 6 baskets from each of the 24 ice condenser bays and shall be constituted of one basket each from Radial Rows 1, 2, 4, 6, 8 and 9 (or from the same row of an adjacent bay if a basket from a designated row cannot be obtained for weighing) within each bay.
If any basket is found to contain less than 1155 pounds of ice, a l
representative sample of 20 additional baskets from the same bay shall be weighed.
The minimum average weight of ice from the 20 additional baskets and the discrepant basket shall not be less than 1155 pounds / basket at a 95% level of confidence.
l The ice condenser shall also be subdivided into 3 groups of baskets, as follows:
Group 1 - bays 1 through 8, Group 2 -
bays 9 through 16, and Group 3 - bays 17 through 24.
The minimum average ice weight of the sample baskets from Radial Rows 1, 2, 4, 6, 8 and 9 in each group shall not be less than 1155 pounds / basket at a 95% level of confidence.
The minimum total ice condenser ice weight at a 95% level of confidence shall be calculated using all ice basket weights determined during this weighing program and shall not be less than 2,245,320 pounds.
SEQUOYAH - UNIT 2 3/4 6-28 Amendment No. 80, 87, 118
f r
C'ON1AINMe< SYSTEMS ICE CONDENSER DOORS LIMITING CONDITION FOR OPERATION 3.6.5.3 The ice condenser inlet doors, intermediate deck doors, and top deck doors shall be closed and OPERABLE.
APPLICABILITY:
MODES 1, 2, 3 and 4.
ACTION:
With one or more ice condenser doors open or otherwise inoperable, POWER OPERATION may continue for up to 14 days provided the ice bed temperature is monitored at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the maximum ice bed temperature is maintained less than or equal to 27'F; otherwise, restore the doors to their closed positions or OPERABLE status (as applicable) within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.5.3.1 Inlet Doors - Ice condenser inlet doors shall be:
a.
Continuously monitored and determined closed by the inlet door position monitoring system, and b.
Demonstrated OPERABLE at least once per 18 months by:
1.
Verifying that the torque required to initially open each door is less than or equal to 675 inch pounds.
2.
Verifying that opening of each door is not impaired by i e, frost or debris.
3.
Verifying that the torque required to open each door is less than l
195 inch pounds when the door is 40 degrees open.
This torque is defined as the " door opening torque" and is equal to the nominal door torque plus a frictional torque component.
l SEQUOYAH - UNIT 2 3/4 6-30 Amendment No.13, 118
[
s s
TONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4.
Verifying that the torque required to keep each door from closing l
is greater than 78 inch-pounds when the door is 40 degrees open.
This torque is definec as the " door closing torque" and is equal to the nominal door torque minus a frictional torque component.
5.
Calculation of the frictional torque of each door tested in accordance with 3 and 4, above.
The calculated frictional torque shall be less than or equal to 40 inch pounds.
4.6.5.3.2 Intermediate Deck Doors - Each ice condenser intermediate deck door shall be:
a.
Verified closed and free of frost accumulation by a visual inspection at least once per 7 days, and b.
Demonstrated OPERABLE at least once per 18 months by visually verifying l
no structural deterioration, by verifying free movement of the vent assemblies, and by ascertaining free movement when lifted with the applicable force shown below:
Door Liftina Force 1.
0-1, 0-5 1 33 lbs.
l l
2.
0-2. 0-6 5 30 lbs.
3.
0-3, 0-7 1 28 lbs.
4.
0-4, 0-8 1 28 lbs.
4.6.5.3.3 Top Deck Doors - Each ice condenser top deck door shall be determined closed and OPERABLE at least once per 92 days by visually verifying:
a.
That the doors are in place, and b.
That no condensation, frost, or ice has formed on the doors or blankets which would restrict their lif ting and opening if required.
l l
1 l
l l
l SEQUOYAH - UNIT 2 3/4 6-31 Amendment No.13, 118 i
e
f f
j a
s CONTAINMENT SYSTEMS INLET 000R POSITION MONITORING SYSTEM LIMITING CONDITION FOR OPERATION 3.6.5.4 The inlet door position monitoring system shall be OPERABLE.
APPL!CABILITY:
MODES 1, 2, 3 and 4.
ACTION:
With the inlet door position monitoring system inoperable, POWER OPERATION may continue for up to 14 days, provided the ice bed temperature monitoring system is OPERABLE and the maximum ice bed temperature is less than or equal to 27'F when monitored at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, otherwise, restore the inlet door position monitoring system to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at l6ast HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> SURVEILLANCE REQUIREMENTS 4.6.5.4 The inlet door position monitoring system shall be determined OPERABLE by:
a.
Performing a CHANNEL CHECK at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, b
Performing a CHANNEL FUNCTIONAL TEST at least once per 18 months, and c.
Verifying that the monitoring system correctly indicates the status l
of each inlet door as the door is opened and reclosed during its testing per Specification 4.6.5.3.1.
1 l
l l
SEQUOYAH - UNIT 2 3/4 6-32
1
(
t
.0 s
I CONTAINMENT SYSTEMS BASES i
3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be avai14919 tn maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions.
Either recombiner unit or the hydrogen mitigation system, consisting of 68 hydrogen igniters per unit, is capable of controlling the expected hydrogen generation associated with 1) Zirconium-water reactions, 2) radiolytic decomposition of water and 3) corrosion of metals within containment. These hydrogen control systems are designed to mitigate the effects of an accident as described in Regulatory Guide 1.7, " Control of Combustible Gas Concentrations in Containment following a LOCA," Revision 2, dated November 1978.
Tne hydrogen mixing systems are provided to ensure adequate mixing of the containment atmosphere following a LOCA.
This mixing action will prevent localized accumulations of hydrogen from exceeding the flammable limit.
The operability of at least 66 of 68 igniters in the hydrogen control distributed ignition system will maintain an effective coverage throughout the containment.
This system of ignitors will initiate combustion of any signifi-cant amount of hydrogen released after a degraded core accident.
This system is to ensure burning in a controlled manner as the hydrogen is released instead of allowing it to be ignited at high concentrations by a random ignition source.
3/4.6.5 ICE CONDENSER The requirements associated with each of the components of the ice condenser ensure that the overall system will be available to provide sufficient pressure suppression capability to limit the containment peak pressure transient to less than 12 psig during LOCA conditions.
3/4.6.5.1 ICE BE0 The OPERABILITY of the ice bed ensures that the required ice inventory will 1) be distributed evenly through the containment bays, 2) contain suffi-cient boron to preclude dilution of the containment sump following the LOCA and 3) contain sufficient heat removal capability to condense the reactor system volume released during a LOCA.
These conditions are consistent with the assumptions used in the accident analyses.
The minimum weight figure of 1155 pounds of ice per basket contains a 15%
l conservative allowance for ice loss through sublimation which is a factor of 15 higher than assumed for the ice condenser design.
The minimum weight i
figure of 2,245,320 pounds of ice also contains an additional 1% conservative I
allowance to account for systematic error in weighing instruments.
In the event that observed sublimation rates are equal to or lower than design predictions after three years of operation, the minimum ice baskets weight may be adjusted downward.
In addition, the number of ice baskets required to be weighed each 9 months may be reduced after 3 years of operation if such a reduction is supported by observed sublimation data.
SEQUOYAH - UNIT 2 B 3/4 6-4 Amendment No. 21 118
.-