ML20217K873
| ML20217K873 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| Issue date: | 10/18/1999 |
| From: | VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | |
| Shared Package | |
| ML20217K869 | List: |
| References | |
| GL-99-02, NUDOCS 9910270011 | |
| Download: ML20217K873 (8) | |
Text
I.
VERMONT YANKEE NUCLEAR POWER CORI' ORATION I: _
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Docket No.50-27i BVY 99-132 Attachment 3 -
l Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 227 Revised Testing of Activated Charcoal Marked-up Version of the Current Technical Specific tien Pages l
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VYNPS i 3.7 LIMITING CONDITIONS FOR 4.7 OPERATION SURVEILLANCE REQUIREMENTS Treatment System 2. a. The tests and and an alternate sample analysis of electrical power Specification source, consisting of the associated 3.7.B.2 shall be performed initially Emergency Diesel and at least once Generator or Vernon per operating cycle tie, for each not to excend standby gas 16 months, and treatment circuit following painting, shall be operable fire or chemical
.at all times when release in any secondary ventilation zone containment communicating with integrity is the system, while required. the system is operating, that
- 2. a. The results of the in-place cold DOP could contaminate and halogenated the HEPA filters or hydrocarbon tests charcoal adsorbers.
at design flows on b. Cold DOP testing HEPA and charcoal shall be performed filter banks shall after each complete show 2,99% DOP or partial removal and >994 replacement of the halogenated ~ HEPA filter bank.
hydrocarbon removal. c. Halogenated hydrocarbon testing
- b. The results of shall be performed laboratory carbon / ~ > 97, f '/, after each complete (30 *C I 70 */o gg ) sample ana shall show radioactiv g(
1 or partial replacement of the charcoal filter iodide removal. bank.
((1600G( 954/ RHO.
Laboratory analysis In addition, the results shall be sample analysis of verified acceptable Specification within 31 days 3.7.B.2.b and the following sample halogenated removal or the hydrocarbon test applicable train of shall be performed the Standby Gas after every Treatment System shall be considered 720 hours of normal l system operation.
in-operable and the requirements of d. Each circuit shall Specification- be operated with 3.7.B.3 shall the heaters on at apply. least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> every month,
- c. System fans shall be shown to operate e. An ultrasenic leak within t10% of test shall be design flow. performed on the gaskets sealing the housing panels downstream of the HEPA filters and adsorbers at least Amendment No. +G, 44, 143 153
VYNPS BASES: 3.7 (Cont'd)
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The Standby Gas Treatment System (SGTS) is designed to filter and exhaust the Reactor Building atmosphere to the stack during secondary co'ntainment isolation conditions, with a minimum release of radioactive j materials from the Reactor Building to the environs. To insure that the standby gas treatment system will be effective in removing l radioactive contaminates from the Reactor Building air, the system is tested periodically to meet the intent of ANSI N510-1975. Both standby gas treatment fans are designed to automatically start upon containment isolation and to maintain the Reactor Building pressure to approximately a negative 0.15 inch water gauge pressure; all leakage should be in-leakage. Should the fan fail to start, the redundant alternate fan and filter system is designed to start automatically.
Each of the two fans has 100% capacity. This substantiates the availability of the operable circuit and results in no added risk; thus, reactor operation or refueling operation can continue. If neither circuit is operable, the plant is brought to a condition where the system is not required.
When the reactor is in cold shutdown or refueling the drywell may be open and the Reactor Building becomes the only containment system.
During cold shutdown the probability and consequences of a DBA LOCA are !
substantially reduced due to the pressure and temperature limitations l in this mode. However, for other situations under which significant l radioactive release can be postulated, such as during operations with a l potential for draining the reactor vessel, during core alterations, or during movement of irradiated fuel in the secondary containment, operability of standby gas treatment is required. An alternate electrical power source for the purposes of Specification 3.7.B.l.b shall consist of either an Emergency Diesel Generator (EDG) or the Vernon Hydro tie line. Maintaining availability of the Vernon Hydro tie line as an alternative to one of the EDGs in this condition provides assurance that standby gas treatment can, if required, be i operated without placing undue constraints on EDG maintenance availability. Inoperability of both circuits of the SGTS or both EDGs during refueling operations requires suspension of activities that represent a potential for releasing radioactive material to the secondary containment, thus placing the plant in a condition that minimizes risk.
Use of the SGTS, without the fan and the 9 kW heater in operation, as a vent path-during torus venting does not impact subsequent adsorber capability because of the very low flows and because humidity control is maintained by the standby 1 kW heaters, therefore operation in this manner does not accrue as operating time.
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D. Primary Containment Isolation Valves Double isolation valves are provided on lines that penetrate the primary containment and communicate directly with the reactor vessel and on lines that penetrate the primary containment and communicate l
with the primary containment free space. Closure of one cf the valves l in each line would be sufficient to maintain the integrity of the l pressure suppression system. Automatic initiation is required to '
minimize the potential leakage paths from the containment in the event of a loss-of-coolant accident.
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Amendment No. 46, 44, 143 166
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VYNPS l
__ BASES: 4.7 (Cont'd)
The test frequencies are adequate to detect equipment deterioration prior to significant defects, but the tests are not frequent enough to load the filters, thus reducing their reserve capacity too l quickly. That the testing frequency is adequate to detect deterioration was demonstrated by the tests which showed no loss of filter efficiency after 2 years of operation in the rugged shipboard i i
environment on the NS Savannah (ORNL 3726). Pressure drop tests l across filter sections are performed to detect gross plugging of the i filter media. Considering the relatively short time that the fans may be run for test purposes, plugging is unlikely, and the test interval is reasonable. Such heater tests will be conducted once during each operating cycle. Considering the simplicity of the heating circuit, the test frequency is sufficient. Air distribution j tests will be conducted once during each operating cycle.
The in-place testing of charcoal filters is performed using a i l halogenated hydrocarbon, which is injected into the system upstream of the charcoal filters. Measurements of the challenge gas concentration upstream and downstream of the charcoal filters is made. The ratio of the inlet and outlet concentrations gives an overall indication of the leak tightness of the system. Although this is basically a leak test, since the filters have charcoal of known efficiency and holding capacity for elemental iodine and/or methyl iodine, the test also gives an indication of the relative efficiency of the installed system.
High-efficiency particulate air filters are installed before and I I
after the charcoal filter to minimize potential release of particulates to the environment and to prevent clogging of the iodine filters. An efficiency of 99% is adequate to retain particulates that may be released to the Reactor Building following an accident.
This will be demonstrated by testing with Dop as testing medium.
The efficiencies of the particulate and charcoal filters are sufficient to prevent exceeding 10CFR100 limits for the accidents analyzed. The analysis of post-accident hydrogen purge assumed a charcoal filter efficiency of 95%. Hence requiring in-place test ef ficiencies of 99% for these filtersrprovides adequate margin._f e labo atory . ethyl / iodide femoval/ test is/pertowd at 95V relati e hum'dity 0%. assupeadeWtemarginover[thedes/gnrelapvehum ity F
The test interval for filter efficiency was selected to minimize plugging of the filters. In addition, testing for methyl iodid-removal efficiency will be demonstrated. This will be done either by removal of a charcoal sample cartridge which contains charcoal equivalent to the bed thickness or removing one adsorber tray from the system and using the charcoal therein, after mixing, to obtain at least two samples equivalent to the bed thickness. Any HEPA filters found defective should be replaced with filters qualified according to Regulatory Position C.3.d of Regulatory Guide 1.52. If laboratory test results are unacceptable, all charcoal adsorbent in the system should be replaced with charcoal adsorbent qualified according to Regulatory Guide 1.52.
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Amendment No. 15 170
VERMONT YANKEE NUCLEAR POWER CORPORATION l
. . Docket No. 50-271 BVY 99-132
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l Attachment 4 I
Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 227 l
i I
Revised Testing of Activated Charcoal Revised Technical Specification Pages i
1 VYNPS !
3.7 LIMITING CONDITIONS FOR 4.7 SURVEILLANCE REQUIREMENTS OPERATION Treatment System 2. a. The tests and and an alternate sample analysis of electrical power Specification source, consisting 3.7.B.2 shall be of the associated performed initially Emergency Diesel and at least once Generator or Vernon per operating cycle tie, for each not to exceed standby gas 18 months, and treatment circuit following painting, shall be operable fire or chemical at all times when release in any secondary ventilation zone containment communicating with l integrity is the system, while l required. the system is operating, that
- 2. a. The results of the could contaminate in-place cold DOP the HEPA filters or and halogenated charcoal adsorbers.
hydrocarbon tests at design flows on b. Cold DOP testing HEPA and charcoal shall be performed i filter banks shall after each complete I show 299% DOP or partial removal and 299% replacement of the halogenated HEPA filter bank.
hydrocarbon removal. c. Halogenated hydrocarbon testing !
- b. The results of shall be performed laboratory carbon after each complete sample analysis or partial shall show 297.5% replacement of the i radioactive methyl charcoal filter iodide removal bank.
(30*C, 70% RH).
Laboratory analysis In addition, the results shall be sample analysis of verified acceptable Specification within 31 days 3.7.B.2.b and the following sample halogenated removal or the hydrocarbon test applicable train of shall be performed the Standby Gas after every Treatment System 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of normal shall be considered system operation.
in-operable and the requirements of
- d. Each circuit shall be operated with Specification the heaters on at 3.7.B.3 shall least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> apply.
every month.
sh w within 110% of p ate f[g[ ((** "f **
performed on the design flow.
gaskets sealing the housing panels downstream of the HEPA filters and adsorbers at least Amendment No. 44, 49, 443 153
I VYNPS l
BASES: 3.7 (Cont'd) !
The Standby Gas Treatment System (SGTS) is designed to filter and exhaust the Reactor Building atmosphere to the stack during secondaay l containment isolation conditions, with a minimum release of radioactive materials from the Reactor Building to the environs. To insure that the standby gas treatment system will be effective in removing radioactive contaminates from the Reactor Building air, the system is tested periodically to meet the intent of ANSI N510-1975. Laboratory charcoal testing will be performed in accordance with ASTM D3803-1989, except, as allowed by GL 99-02, testing can be performed at 70%
relative' humidity for systems with humidity control. Both standby gas treatment fans are designed to automatically start upon containment isolation and to maintain the Reactor Building pressure to approximately a negative 0.15 inch water gauge pressure; all leakage should be in-leakage. Should the fan fail to start, the redundant alternate fan and filter system is designed to start automatically.
Each of the two fans has 100% capacity. This substantiates the availability of the operable circuit and results in no added risk; thus, reactor operation or refueling operation can continue. If neither circuit is operable, the plant is brought to a condition where the system is not required.
When the reactor is in cold shutdown or refueling the drywell may be open and the Reactor Building becomes the only containment system. l During cold shutdown the probability and consequences of a DBA LOCA are l substantially reduced due to the pressure and temperature limitations in this mode. However, for other situations under which significant radioactive release can be postulated, such as during operations with a potential for draining the reactor vessel, during core alterations, or during movement of irradiated fuel in the secondary containment, operability of standby gas treatment is required. An alternate electrical power source for the purposes of Specification 3.7.B.l.b. ;
shall consist of either an Emergency Diesel Generator (EDG) or the l Vernon Hydro tie line. Maintaining availability of the Vernon Hydro tie line as an alternative to one of the EDGs in this condition provides assurance that standby gas treatment can, if required, be operated without placing undue constraints on EDG maintenance availability. Inoperability of both circuits of the SGTS or both EDGs during refueling operations requires suspension of activities that represent a potential for releasing radioactive material to the secondary containment, thus placing the plant in a condition that minimizes risk.
Use of the SGTS, without the fan and the 9 kW heater in operation, as a vent path during torus venting does not impact subsequent adsorber capability because of the very low flows and because humidity control is maintained by the standby 1 kW heaters, therefore operation in this manner does not accrue as operating time.
D. Primary Containment Isolation Valves Double isolation valves are provided on lines that penetrate the primary containment and communicate directly with the reactor vessel and on lines that penetrate the primary containment and communicate with the primary containment free space. Closure of one of the valves in each line would be sufficient to maintain the integrity of the pressure suppression system. Automatic initiation is required to minimize the potential leakage paths from the containment in the event of a loss-of-coolant accident.
Amendment No. 44, 44, 444 166
1, VYNPS BASES: 4.7-(Cont'd)
The test frequencies are adequate to detect equipment deterioration prior to significant defects, but the tests are not frequent enough to load the filters, thus reducing their reserve capacity too quickly.
That the testing frequency is adequate to detect deterioration was demonstrated by the tests which showed no loss of filter efficiency efter 2 years of operation in the rugged shipboard environment on the NS Savannah - (ORNL 3726) . Pressure drop tests across filter sections are performed to detect gross plugging of the filter media.
Considering the relatively short time that the fans may be run for test purposes, plugging is unlikely, and the test interval is reasonable.
Such heater tests will be conducted once during each operating cycle.
'Considering the simplicity of the heating circuit, the test frequency is sufficient. Air distribution tests will be conducted once during each. operating cycle.
The in place testing of charcoal filters is performed using a halogenated hydrocarbon, which is injected into the system upstream of the charcoal filters. Measurements of the challenge gas concentration upstream and downstream of the charcoal filters is made. The ratio of the inlet and outlet concentrations gives an overall indication of the leak tightness of the system. Although this is basically a leak test, since the filters have charcoal of known efficiency and holding capacity for elemental iodine and/or methyl iodine, the test also gives an indication of the relative efficiency of the installed system.
High-efficiency particulate air filters are installed before and after the charcoal filter to minimize potential release of particulates to the environment and to prevent clogging of the iodine filters. An efficiency of 99% is adequate to retain particulates that may be released to the Reactor Building following an accident. This will be demonstrated by testing with DOP as testing medium.
The efficiencies of the particulate and charcoal filters are sufficient to prevent exceeding 10CFR100 limits for the accidents analyzed. The analysis of post-accident hydrogen purge assumed a charcoal filter efficiency of 95%. Hence requiring in-place test efficiencies of 99%
for these filters and a laboratory methyl iodide test of 97.5% for the charcoal provides adequate margin.
The test interval for filter efficiency was selected to minimize plugging of the filters. In addition, testing for methyl iodide removal efficiency will be demonstrated. This will be done either by removal of a charcoal sample cartridge which contains charcoal equivalent to the bed' thickness or removing one adsorber tray from the system and using the charcoal therein, after mixing, to obtain at least
'two samples equivalent to'the bed thickness. Any HEPA filters found defective should be replaced with filters qualified according to Regulatory Position.C.3.d of Regulatory Guide 1.52. If laboratory test results are unacceptable,'all charcoal adsorbent in the system should be replaced with charcoal adsorbent qualified according to Regulatory Guide 1.52.
' Amendment No. 44 170
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