ML20196L830
| ML20196L830 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/14/2020 |
| From: | Vistra Operating Co. (VistraOpCo) |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20196L876 | List: |
| References | |
| Download: ML20196L830 (6) | |
Text
Table 1 Inservice Tests Requested for Deferral to 1RF22 Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief 1
1CT-0145 Low Risk U1 CS TRN B HDR IRC CHK VLV Disassembly Examination ISTC-5221(c)(3),
one valve each outage This check valve has both open and close safety function positions. Open tests of valves in this group with flow are not practical as they would require or risk spraying down containment or fill of containment recirculation sumps. Local Leak Rate Testing is not required since this valve has a water filled loop seal.
Therefore, the disassembly examination monitors both the open and close safety functions of this valve. This valve and entire 4-valve group are not subject to wear inducing service or degradation. During the last two disassembly examinations of each valve in the group, the manual full stroke exercise, verification that valve internals were structurally sound (no loose or corroded parts), and visual inspection of the valve body (for disc contact), disc, and seat for indications of damage or degradation were completed satisfactory (SAT).
These check valves are not subject to wear inducing service or degradation and past acceptable performance supports reasonable assurance that the check valve would continue to be capable of performing its safety function during the extended interval. Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR.
Therefore, the requirement to disassemble and examine one valve this outage could be contrary to the health and safety of plant personnel during the current COVID-19 pandemic. Relief pursuant to 10 CFR 50.55a(z)(2) will allow CPNPP to defer the disassembly examination of any members of this group from 1RF21 to 1RF22.
2 1FW-0076 Low Risk SG 1-02 FW HDR CHK VLV Disassembly Examination ISTC-5221(c)(3),
one valve each outage The safety function position of this check valve is closed. Due to water hammer interlocks and the difficulty of alternate test methods, it is not practical to monitor the close function of the check valve in any other manner. The close function is redundant with the Feedwater Isolation and Isolation Bypass valves, which are exercised tested once each cycle. The non-safety open function is monitored in 002 Attachment CPNPP IST Relief Request Table 1 Page 1 of 6
Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief regular use by verification that Main Feedwater flow to the 1-02 Steam Generator is not impaired. This valve is in a group of 4 valves whose disassembly examinations are staggered over a 6-year interval. All valves and their internals have been installed and in service over the life of the plant (except for outage periods). During the last two disassembly examinations of each valve in the group, the manual full stroke exercise, verification that valve internals were structurally sound (no loose or corroded parts), and visual inspection of the valve body (for disc contact), disc, and seat for indications of damage or degradation were completed satisfactory. Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR. Based on this history, the requirement to disassemble and examine this valve during 1RF21 could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer the disassembly examination of any members of this group from 1RF21 to 1RF22.
3 1CS-8442 Low Risk U1 EMER BORATE LN CHK VLV Disassembly Examination ISTC-5221(c)(3),
one valve each outage The safety function position of this valve is open, and its functional capability is confirmed each cycle during the Boration Flow Verification test. The disassembly examination monitors the non-safety close capability of the valve to meet bi-directional testing requirements. This valve is in a disassembly group of one valve. At the 2013 inspection, the plug was replaced due to an UNSAT Blue check. As left plug and bore measurements of this piston check valve were recorded indicating that diametrical clearance was like new and that there were no indications of bore ovality after over 20 years of service. During the last two disassembly examinations of the valve, the manual full stroke exercise, verification that valve internals were structurally sound (no loose or corroded parts), and visual inspection of the valve bore, disc, and seat for indications of damage or degradation were completed satisfactory. Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified 002 Attachment CPNPP IST Relief Request Table 1 Page 2 of 6
Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief that would impact or degrade each valves performance capability and exclude it from this interval extension RR. The requirement to disassemble and examine this valve during 1RF21 could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer the disassembly examination of this valve from 1RF21 to 1RF22.
4 1DO-0050 Low Risk DG 1-02 FO DAY TK 1-02 XFER HDR CHK VLV Disassembly Examination ISTC-5221(c)(3),
one valve each outage The safety function position of 1DO-0050 is open, and its open function capability is confirmed during each operation of the Train B Emergency Diesel Generator and test of the Train B Fuel Oil Transfer Pumps. The disassembly examination monitors the non-safety close function of the valve to meet bi-directional testing requirements. This valve is in a disassembly group of two valves. At the 2014 examination of 1DO-0050, plug and bore measurements of this piston check valve were recorded indicating that diametrical clearance and bore ovality remained in tolerance (with greater than 50% margin for wear) after 24 years of service.
At the 2016 examination of sister valve 1DO-0049, plug and bore measurements indicated that diametrical clearance and bore ovality remained in tolerance (with greater than 50% margin for wear) after 26 years of service. During the last two disassembly examinations of both valves, the manual full stroke exercise, verification that valve internals were structurally sound (no loose or corroded parts), and visual inspection of the valve bore, disc, and seat for indications of damage or degradation were completed satisfactory.
Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR. The requirement to disassemble and examine this valve during 1RF21 could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer the disassembly examination of any members of this group from 1RF21 to 1RF22.
002 Attachment CPNPP IST Relief Request Table 1 Page 3 of 6
Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief 5
6 7
8 9
10 11 1MS-0022 1MS-0025 1MS-0058 1MS-0096 1MS-0129 1MS-0130 1MS-0133 All Low Risk Main Steam Safety Valves Relief Valve Test I-1320(a), 5-Year Interval
& 20% every 24-months Over the last two 5-year testing cycles for this 20-member valve group, no additional valves have required testing per I-1320(c)(1). Of the 40 tests reviewed, a set pressure adjustment was required to achieve an as left setting of
+/- 1% of the required set pressure during 12 of the 40 tests.
For each valve, set pressure adjustment was required only one time over the last two testing cycles. Of the 12 valves which required adjustment, extrapolation of their set point drift to a 6-year test interval shows that their anticipated as-found values fall within acceptance criteria with 4 PSIG margin to the +/- 3% as-left acceptance criteria. Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR.
Therefore, a 6-year interval is acceptable, and one-time relief is requested from the requirement to test each MSSVs at least once every 5 years on the basis that the requirement could be detrimental to the occupational health and safety of plant personnel. Additionally, between 1RF21 and 1RF22, one-time relief from the requirement to test a minimum of 20% of the valves from each valve group within any 24-month interval is requested since compliance with this requirement could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer testing of any members of this group of relief valves from 1RF21 to 1RF22.
12 1DO-0111 Low Risk DG 1-01 FO XFER PMP 1-01 DISCH RLF VLV Relief Valve Test I-1350(a), 10-year Test Interval and 20% every 48-months 1DO-0111 is in a group of 8 valves. For this 8-valve group, there have only been two test failures during the last two successive tests of each valve in the group. One failure was due to exceeding seat tightness acceptance criteria (1SI-0176) and the other was due to exceeding set pressure acceptance criteria (1-8121). In both cases, past operability evaluations concluded that the valves were OPERABLE with the identified conditions. 1DO-0111 performed consistently during the last two successive tests without the need for adjustment and set pressure drift of only 1 psi over a 9-year interval.
1-8121 experienced 002 Attachment CPNPP IST Relief Request Table 1 Page 4 of 6
Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief high set point drift over the last interval and is excluded from this extension request for this reason. With the exception of 1-8121, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR. Therefore, extension of the group test interval is acceptable.
Between 1RF21 and 1RF22, one-time relief from the requirement to test a minimum of 20% of the valves from each valve group within any 48-month interval is requested since compliance with this requirement could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer testing of all members of this group of relief valves, except 1-8121, from 1RF21 to 1RF22.
13 1-8855A Low Risk SI ACCUM 2-01 RLF VLV Relief Valve Test I-1350, 20%
every 48-months 1-8855A is in a group of 4 valves which provide overpressure protection for their respective Safety Injection Accumulator. During the last two successive tests of each valve in the group, only one valve failed as-found set pressure testing. All other as-found tests (visual inspection, seat tightness, and set pressure) for the other valves were satisfactory, and set pressure adjustment has been required on only one occasion. The one set pressure test failure of 1-8855D was attributed to compression set of the new O-ring. Despite the test failure, the valve was capable of performing as designed since it would have provided adequate overpressure protection for the respective accumulator and passed seat tightness testing. Since the latest test of any of these valves in the group was in 2014, the requested group extension will not result in any valve exceeding its 10-year maximum interval. 1-8855A performed consistently over the previous test interval with virtually no set point drift.
Furthermore, no deficiencies, adverse trends or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this interval extension RR. Therefore, extension of the group test interval is acceptable. Between 1RF21 and 1RF22, one-time relief from the requirement to 002 Attachment CPNPP IST Relief Request Table 1 Page 5 of 6
Valve ID
& Risk Rank Component Description Inservice Test Type Applicable ASME OM Code Requirement Basis for Relief test a minimum of 20% of the valves from each valve group within any 48-month interval is requested since compliance with this requirement could be detrimental to the occupational health and safety of plant personnel. Relief will allow CPNPP to defer testing of any members of this group of relief valves from 1RF21 to 1RF22.