ML20149L795
| ML20149L795 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 11/12/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20149L794 | List: |
| References | |
| NUDOCS 9611180113 | |
| Download: ML20149L795 (7) | |
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p ato g UNITED STATES 4
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NUCLEAR REGULATORY COMMISSION
't WASHINGTON, D.C. 20N1
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM ILLIN0IS POWER COMPANY CLINTON POWER STATION DOCKET NUMBER 50-461 By letter dated July 29, 1996, Illinois Power Company submitted two requests for relief from the requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, 1980 Edition l
through Winter 1981 Addenda. These requests were with regard to the performance of leakage and pressure testing for primary containment isolation 4
valves and selected ASME Code Class 2 pressure retaining components penetrating the drywell and primary containment.
i RELIEF REQUEST 1004 Backaround Relief Request 1004 would allow a change in the required frequency of pressure testing of certain ASME Code Class 2 components penetrating the drywell and primary containment. The propcsed change in test frequency will correspond to recent changes in test frequencies authorized by 10 CFR Part 50, Appendix J -
Option B (Amendment No. 105) and the drywell bypass leak rate test (Amendment No. 106).
Piping systems included in Relief Request 1004 penetrating the drywell include:
Fire Protection, Instrument Air, Service Air, Leak Detection, Cycled Condensate, Plant Chilled Water, Containment / Auxiliary / Fuel Buildings Equipment Drains, and Containment / Auxiliary / Fuel Buildings Floor Drains.
Additionally, piplng systems included in Relief Request 1004 penetrating primary containment include: Containment Monitoring, Suppression Pool Clean-Up and Transfer, Suppression Pool Make-Up, Reactor Core Isolation Cooling, and Containment Building HVAC.
Code Reautrements The 19P4 Edition, Winter 1981 Addenda of ASME Section XI, Table IWC-2500-1, Examination Category C-H, Item C7.30 through C7.80 requires a system pressure test each inspection period and a system hydrostatic test each inspection interval.
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9611100113 961112 PDR ADOCK 05000461 P
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- l. f Alternative Testina Pronosed j
As an alternative to ASME Section XI pressure testing requirements for the
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components identified above, the licensee proposed to perform pressure testing at the frequencies required by Appendix J - Option B, and the drywell bypass i
leak rate test (as required by the technical specifications), in lieu of the j
frequencies specified in ASME Section XI, Table IWC-2500-1, Category C-H.
f Staff Evaluation The applicable edition of Section XI of the ASME Code for the Clini.cn Power L
Station (CPS) first ten-year ISI program is the 1980 Edition through winter j
i 1981 addenda.
IWC-1220 of the 1980 Edition of ASME Section XI for CPS exempts l
the following components from the inservice examination requirements of IWC-l 2500:
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" Components of systems or portions of systems that during normal plant operating conditions are not required to operate or perform a system function but remain flooded under static conditions at a pressure of at 4
i least 80% of the pressure that the component or system will be subject J
l to when required to operate," er l
" Components ot :,ystems or portions of systems, other than Residual Heat j
Removal Systems (RHR) and Emergency Core Cooling systems (ECCS), that j
are not required to operate above a pressure of 275 psig or above a j
temperature of 200 degrees Fahrenheit," or i
" Component connections, piping and associated valves, and vessels and l
their attachments that are 4 in, nominal pipe size and smaller."
The components identified in Relief Request 1004 are neither a part of the RHR nor a part of the ECCS.
In addition, they are not required to operate above a pressure of 275 psig or above a temperature of 200 degrees Fahrenheit. Per IWC-1220 stated above, these components are exempt from Section XI inservice examination requirements and, hence, are not required to be pressure tested.
Since the affected components are not required to be tested, a relief request is not required.
As stated above, the applicable edition of the ASME Code for the first ten-year ISI program at the CPS is the 1980 Edition, Winter 1981 Addenda.
i However, pursuant to 10 CFR 50.55a(g)(4), the second ten-year ISI program for the CPS must comply with the requirements of the 1989 ASME Code Section XI.
The 1989 ASME Code Section XI is the latest ASME code edition referenced in 10 CFR 50.55a, and contains revised requirements which do not apply to the licensee's first ten-year ISI program. The staff notes that when updating the ISI program for the second ten-year interval, the licensee should review the revised code requirements for those components identified in Relief Request i
1004, determine to what extent the requirement changes should be implemented, and if necessary, submit requests for relief from the 1989 ASME Code Section XI.
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j f RELIEF REQUEST 2037 i
j' Backaround j
The Code of Federal Regulatfons, 10 CFR 50.55a, requires that inservice i
testing (IST) of certain American Society of Mechanical Engineers (ASME) Code j
Class 1, 2, and 3 pumps and valves be performed in accordance with Section XI of the ASME Sof fer and Pressure Vessel Code (the Code) and applicable addenda, except where alternatives have been authorized or relief has been requested by the licensee and granted by the Commission pursuant to Sections (a)(3)(1),
j (a)(3)(11), or (f)(6)(1) of 10 CFR 50.55a.
In proposing alternatives or i
requesting relief, the licensee must demonstrate that:
(1) the proposed alternatives provide an acceptable level of quality and safety; (2) compliance 1
would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety; or (3) conformance is impractical for its i
j facility. Section 50.55a authorizes the Commission to approve alternatives l
l and to grant relief from ASME Code requirements upon making the necessary j
findings. Additionally, paragraph (f)(4)(iv) of Section 50.55a provides that i
IST of pumps and valves may meet the requirements set forth in subsequent i
editions and addenda of the Code that are incorporated by reference in paragraph (b) of Section 50.55a, subject to the limitations and modifications listed therein, and subject to Commission approval.
Portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met. Guidance related to the development and implementation of IST programs is given in Generic Letter (GL) 89-04, i
" Guidance on Developing Acceptable Inservice Testing Programs," issued April 3,1989, and its Supplement 1 issued April 4,1995. Also see NUREG-j 1482, " Guidelines for Inservice Testing at Nuclear Power Plants."
l The 1989 Edition of the ASME Code is the latest edition incorporated by reference in paragraph (b) of Section 50.55a.
Subsection IW, which gives the j
requirements for IST of valves, references Part 10 of the American National l
Standards Institute /ASME Operatfons and #afntenance Standards (OM-10) as the rules for IST. OH-10 replaces specific requirements in previous editions of j
Section XI, Subsection IW, of the ASME Code, i
j The NRC published a final rule change to 10 CFR Part 50, Appendix J, " Primary i
Reactor Containment Leakage Testing for Water-Cooled Power Reactors," in the federal Register on September 26, 1995 (60 TR 186, p. 49495). The final rule became effective October 26, 1995. The revised regulations provide a performance-based option for leakage-rate testing of containments (" Option B").
Licensees may voluntarily adopt the option in lieu of compliance with the prescriptive requirements in the regulation (" Option A").
The NRC issued the change as part of an effort to improve the focus of regulations by eliminating prescriptive requirements that are marginal to safety. The final rule allows leakage test intervals to be based on system and component performance. Thus, licensees have greater flexibility for cost-effective implementation methods in satisfying regulatory safety objectives.
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j-Operating License Amendment 105 allows Illinois Power Company to implement Option B of Appendix J and to establish a performance-based leakage-rate test interval for the containment isolation valves subject to leakage testing.
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By letter dated July 29, 1996, Illinois Power Company submitted a request for j
the Clinton Power Station IST Program.
Illinois Power Company requested NRC i
approval of an alternative to the valve leakage testing requirements of the l
1980 Edition, with adden.fa through the 1981 Addenda, of the ASME Code. The alternative applies to the IST program for the Clinton Power Station and will i
allow the licensee, Illinois Power Company, to implement Option B of 10 CFR l
Part 50, Appendix J, as discussed above.
l Code Reauirements The 1980 Edition, with addenda through the 1981 Winter Addenda, of Section XI of the ASME Code, includes requirements for valve leak rate testing in paragraphs IWV-3421 through IWV-3427. These rules are applicable to all Category A valves (i.e., valves for which seat leakage is limited to a specific maximum amount in the closed position for fulfillment of their i
function). Position 10 of GL 89-04 indicated that all containment isolation valves included in the Appendix J program should be included in the IST j
program as Category A valves (or Category A/C for check valves that have a leaktight function for containment isolation).
In Position 10, the NRC said that the valve leakage-rate testing requirements of Appendix J were considered equivalent to the requirements of IWV-3421 through IWV-3425, but that l
licensees must comply with the analysis of leakage rates and corrective action i
requirements of IWV-3426 and IWV-3427(a).
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The requirements of IWV-3421 through IWV-3425 apply to the scope, frequency, i
differential test pressure, seat leakage measurement, and test medium.
l Paragraph IWV-3422 requires a test frequency of at least once every 2 years.
The leakage-rate testing of valves in Appendix J at the time GL 89-04 was issued (and the current Option A of Appendix J) requires that tests shall be performed during each reactor shutdown for refueling, but in no case at intervals greater than 2 years. The performance-based interval in the new l
Option B of Appendix J cannot be considered equivalent to the frequency required by IWV-3422.
i Paragraph 4.2.2.1 of OM-10 specifies the scope of valve seat leakage-rate j
tests as follows:
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Category A valves shall be leakage tested, except that valves which function in the course of plant operation in a manner that demonstrates functionally adequate seat leak-tightness need not be additionally leakage tested.
In such cases, the valve record shall provide the bases for the conclusion that operational observations constitute satisfactory demonstration.
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1 Paragraph 4.2.2.2 of OM-10 specifies the requirements for containment l
1 solation valves as follows:
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Category A valves, which are containment isolation valves, l
shall be tested in accordance with Federal Regulation i
10 CFR 50, Appendix J. ' Containment isolation valves which j
also provide a reactor coolant-system pressure isolation function shall additionally be tested in accordance with l
para. 4.2.2.3.
1 Paragraph 4.2.2.3 of OM-10 gives the requirements for leakage-rate testing for l
valves other than containment isolation valves, including frequency, differential test pressure, test medium, analysis of leakage rates, and corrective action. The frequency requirements for containment isolation i
valves would be specified by Appendix J.
Paragraph (b)(2)(vii) of j
Section_50.55a modified the requirements of OM-10 for IST of containment isolation valves.
Specifically, paragraph (b)(2)(vii) requires that, when i
using OM-10 for IST, leakage rates for Category A containment isolation valves j
that do not provide a reactor coolant system pressure isolation function must i
be analyzed in accordance with paragraph 4.2.2.3(e) of OM-10 and corrective j
actions for these valves must be made in accordance with paragraph 4.2.2.3(f) of OM-10. The regulations take no other exceptions to the provisions of OM-10. Therefore, conducting IST in accord with OM-10 does not preclude the j
use of Option B of Appendix J for establishing a performance-based leakage monitoring schedule for leak testing containment isolation valves.
Illinois Power Company currently uses the testing requirements of Appendix J in accordance with the guidance of Position 10 of GL 89-04 for containment isolation valve leakage-rate monitoring. The requirements of IW-3426 and IW-3427(a) for the analysis of leakage rates and corrective action are also i
imposed for the IST of these valves.
In accord with IW-3422, a test i
frequency of at least once every 2 years (typically during refueling outages) is currently required for the valves that are " Type C" tested per Appendix J l
(i.e., tests intended to measure containment isolation. valve leakage rates).
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Based on the revisions to Appendix J, allowing extension of the leakage-rate test interval according to the performance of the subject valve, Illinois Power Company requests an alternative to the requirements of IW-3422 for determining the test interval for IST purposes. The request applies to all
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Section XI, Category A valves (as listed in the IST program plan) which l
function as containment isolation valves and are subject to the " Type C" i
testing in accord with 10 CFR Part 50, Appendix J.
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Licensee's Basis for Relief
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The licensee states:
i Illinois Power requests approval for the use of Part 10, i
Paragraph 4.2.2.2, " Containment Isolation Valves," of ASME/ ANSI i
OMa 1988 Addenda to ASME/ ANSI OM 1987 (OM-10) for leak rate testing of containment isolation valves as permitted by 10 CFR j
50.55a paragraph (f)(4)(iv).... Although the leakage test j
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procedures and requirements for primary containment isolation valves specified in 10 CFR 50, Appendix J, are equivalent to the requirements of IW, the frequency of testing cannot be considered equivalent.
Illinois Power received Amendment No. 105 to the Clinton Power Station Operating License on June 27, 1996, which revised the Technical Specifications to be consistent with Option B of 10 CFR 50, Appendix J.
However, the benefits of using i
i the performance based option cannot be realized without approval j
of this ralief request. Since primary containment isolation j
valves are, by definition, ASME Section XI, Category A valves, they are subject to the requirements of IW-3422, " Frequency,"
under the 1980 Edition, Winter 1981 Addenda which is in use by Illinois Power for the remainder of the first ten year interval l
(until 4/17/97). Therefore, Illinois Powe: requests use of Part 4
a 10, Paragraph 4.2.2.2, " Containment Isolation Valves," of i
ASME/ ANSI OMa 1988 Addenda to ASME/ ANSI OM 1987 (OM-10) for leakage rate testing of primary containment isolation valves, j
including the related requirements of Paragraphs 4.2.2.3(e),
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" Analysis of Leakage Rates," and 4.2.2.3(f), " Corrective Action."
e l-Alternative Testina Prooosed The licensee proposes:
I Illinois Power will test Category A valves, which are primary containment isolation valves, in accordance with OH-10 Paragraph 4.2.2.2, including the related requirements of i
Paragraphs 4.2.2.3(e), " Analysis of Leakage Rates," and -
l 4.2.2.3(f), " Corrective Action," at the frequencies required by 10 CFR 50, Appendix J, Option B.
Staff Evaluation The 1989 Edition of the ASME Code was incorporated by reference in rulemaking.
effective September 8, 1992 (57 FR 152, p. 34666). The NRC recommended that licensees update their IST program to the OM Standards referenced in the 1989 Edition of the Code (see NUREG-1482) as alternative requirements to those in earlier editions of the Code. Several plants are conducting valve IST l
programs according to the provisions of OM-10, including plants that revised i
tl' air program to meet the updating provisions of Section 50.55a (i.e., at each 120-month interval) and plants that voluntarily implemented the requirements pursuant to paragraph (f)(4)(iv) of Section 50.55a as recommended in i
i For plants using OM-10 for IST of valves, no conflict exists between j
Appendix J and OM 10 for leakage testing of containment isolation valves.
For i
plants that have not yet updated to the requirements of OM-10, such as Clinton i
Power Station, there is a conflict in the test frequency that would preclude the use of Option B of' Appendix J if no alternative is available.
In issuing the Appendix J rule change, the NRC did not intend to create a conflict for the plants continuing to use earlier editions of the Code.
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l Option 8 specifies that the periodic schedule for valve leakage testing be based on the safety significance and historical performance of each isolation valve to ensure the integrity of the overall containment system as a barrier to fission product release to reduce the risk from reactor accidents.
Performance criteria are given in the regulations. A similar scheduling scheme based on risk-assessment and performance-based criteria is under i
development for IST, but rules have not yet been promulgated in the IST regulations, Section 50.55a.
Because the requirements of Appendix J are acceptable for leakage-rate testing of containment isolation valves, and because Illinois Power Company has already received an Operating Licensee amendment for implementing Option B, it would be inconsistent to preclude the licensee from applying the performance-based criteria to the valves by continuing to impose requirements in an earlier edition of the Code which, in fact, do not conflict with a later NRC approved edition of the Code (see the OM-10 discussion above). The Appendix J j
rule change assessed safety concerns with the extended test intervals and determined that the extended intervals are acceptable. Therefore, the requirements for establishing the test interval for local leakage-rate testing j
pursuant to Appendix J provide an acceptable level of quality and safety compared with continuance of the 2-year test interval required by IW-3422.
This is further evidenced in the NRC approval of OM-10 to defer testing requirements for containment isolation valves to Appendix J.(as modified by the NRC in 10 CFR 50.55a(b)(2)(vii) for analysis of leakage data and corrective actions). The licensee's proposal to use OM-10 for the test frequency includes related requirements for analysis of leakage data and corrective actions.
The licensee's proposal to use the leakage test interval allowed by Option B of 10 CFR Part 50, Appendix J, meets the requirements of the later edition of the Code approved by the NRC in paragraph (b) of 10 CFR 50.55a. Accordingly, the alternative IST test interval is authorized pursuant to 10 CFR 50.55a(f)(4)(iv) provided all the related requirements are met. The related requirements are found in OM-10, paragraphs 4.2.2.3(e) and (f) and are included in the licensee's proposal for the use of OM-10 (1989 Edition of the ASMECode).
Principal Contributors:
J. Huang P. Campbell Date:
November 12, 1996