ML20057A112
| ML20057A112 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 09/08/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057A110 | List: |
| References | |
| NUDOCS 9309130066 | |
| Download: ML20057A112 (7) | |
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'o UNITED STATES
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NUCLEAR REGULATORY COMMISSION g
C WASHINGTON,0. C. 20555 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 83 TO FACILITY OPERATING LICENSE NO. NPF-62 f
j ILLIN0IS POWER COMPANY
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S0YLAND POWER COOPERATIVE. INC.
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CLINTON POWER STATION. UNIT NO. I i
DOCKET NO. 50-461 i
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1.0 INTRODUCTION
j By letters dated February 17 and April 16, 1993, the Illinois Power Company i
(IP, the licensee), requested an amendment to Facility Operating License No.
NPF-62 for the Clinton Power Station (CPS). The proposed amendment would,make l
changes to the CPS Operating License and Technical Specification _(TS) i 3/4.6.1.2, " Primary Containment Leakage," and its associated Bases to reflect the partial exemptions to the requirements of 10 CFR Part 50, Appendix J, Sections III.D.I.(a), III.B.I.(b), III.B.3, and III.D.2 that were granted by i
the NPC on September 7,1993. Additionally, CPS TS 3/4.6.1.2 would be revised to delete references to a previously approved and unrelated one-time exemption j
that is no longer applicable.
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The licensee's requests for partial exemptions from the requirements of 10 CFR l
Part 50, Appendix J, Sections III.A.1.(a) and III.A.5.(b) have been deferred by the staff. These exemptions would have: (1) removed the requirement to stop a Type A test if potentially excessive leakage is identified; and (2) allowed an "as found" Type A test acceptance criterion of L and an "as left" l
acceptance criterion of 0.75 L,.
Thestaffhasdeferredaclionsonthese items pending resolution of current rule-making activities associated with i
Appendix J.
Therefore, these exemption requests will not be addressed in this safety evaluation.
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2.0 EVALUATION Paragraph 2.D of Operating License NPF-62 for the CPS lists the exemptions from the requirements of 10 CFR Part 50 and 10 CFR Part 70 that the NRC has authorized the facility to operate with.
In their letter dated February 17, 1993, the licensee proposed the following two changes to paragraph 2.0 of their Operating License:
1.
Add a new item
"(e) an exemption from the requirement of paragraph III.D.I.(a) to conduct the third Type A test of each 10-year service period when the plant is shut down for the 10-year plant inservice inspections," to reflect NRC approval of this exemption.
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Section III.D.I.(a) of Appendix J to 10 CFR Part 50 requires, in part, that
.. a set of three Type A tests shall be performed at approximately equal l
intervals during each 10-year service period.
The third test of each set l
shall be conducted when the plant is shutdown for the 10-year plant inservice l
inspection."
In their exemption request, the licensee proposed to perform the three Type A tests at approximately equal intervals within each 10-year period, with the third test of each set conducted as close as practical to the end.of the 10-year period. However, there would be no required connection between the Appendix J 10-year interval and the inservice inspection 10-year interval.
The 10-year plant inservice inspection (ISI) is the series of inspections perforced every 10-years in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and Addenda as required by 10 CFR 50.55a. The licentee performs the ISI volumetric, surface, and visual examinations of components j
and system pressure tests in accordance with 10 CFR 50.55a(g)(4) throughout' the 10-year inspection interval. The major-portion of this effort is-j presently being performed every 18 months during the refueling outages, As a result, there is no extended outage in which the 10-year ISI examinations are i
performed.
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There is no benefit to be gained by the coupling requirement cited above in that elements of the CPS ISI program are conducted throughout each 10-year cycle rather than during a refueling outage at the end of the 10-year cycle.
Consequently, the subject coupling requirement offers no benefit either to safety or to the economical operation of the facility.
l Moreover, each of these two surveillance tests (i.e., the Type A tests and the 10-year ISI program) is independent of the other and provides assurances of i
different plant characteristics. The Type A test assures the required leak-J tightness to demonstrate compliance with the guidelines of 10 CFR Part 100.
l The 10-year ISI program provides assurance of the integrity of the structures, systems, and components as well as verifying operational readiness of pumps and valves in compliance with 10 CFR 50.55a. There is no safety-related concern necessitating their coupling in the same refueling outage.
Accordingly, the staff finds that the subject exemption request meets the underlying purpose of the rule.
On this basis, the staff found that the uncoupling of the Type A tests from the 10-year ISI program would not present an undue risk to the public health and safety. Accordingly, the NRC approved the issuance of the subject exemption on September /, 1993.
Based on the above, and because the licensee's proposed change to the Operating License is consistent with the exemption approved by the NRC, the staff finds this change acceptable.
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J 2.
Add a new sentence "The special circumstances regarding the exemption identified in Item (e) above are identified in the safety evaluation accompanying Amendment No. 83 to this license" to identify the safety evaluation describing the referenced exemption.
This change merely identifies where the special circumstances regarding the exemption described in item (e) of paragraph 2.0 of the Operating License are referenced. Since this change does not result in any technical changes to-plant operation requirements, the staff finds this change acceptable.
The licensee is proposing the following changes to the CPS TS:
TS 3.6.1.2 The licensee's proposal makes editorial changes to TS 3.6.1.2 Limiting s
Condition for Operation (LCO) item "a."
The LC0 is currently formatted to allow subitems. However, only one subitem is included and as a result the current format can create confusion. TheproposedchangemerelydeletestiIe colon and the "1."
Since this change is editorial in nature, clarifies the LCO, and does not change the technical requirements of the LCO, the staff finds this change acceptable.
The licensee's proposal also makes editorial changes to TS 3.6.1.2 LC0 items "b"
and "d" by deleting the "#" and "##" footnotes which are no longer applicable. The footnotes document a one-time exemption to Appendix J which permitted excluding the leakage rates for valves IB21-F032A and B from the Type B and C combined leakage rate total. This exemption was approved for the period ending with the startup from the third refueling outage.
Startup from the third refueling outage occurred in May 1992. Since the exemption is no longer applicable, this change is being made to prevent any confusion, and this change does not result in any change to the technical requirements of the LCO, the staff finds this change acceptable.
TS 4.6.1.2.a Surveillance Requirement (SR) 4.6.1.2.a currently requires that "Three Type A Overall Integrated Containment Leakage Rate tests shall be conducted at 40 10 month intervals during shutdown at Pa, 9.0 psig during each 10-year service period. The third test of each set shall be conducted during the shutdown for the 10-year plant inservice inspection."
In order to be consistent with the partial exemption to the requirements of 10 CFR Part 50, Appendix J, Section III.D.1.(a) discussed previously, the licensee's proposal removes the requirement that the third Type A test of each 10-year interval be performed when the plant is shut down for the 10-year plant inservice inspection by deleting the last sentence of SR 4.6.1.2.a.
As noted previously, there is no benefit in coupling the requirements of the 10-year 151 program with those for performing Type A leakage rate tests.
Each of these two surveillance tests (i.e., the Type A tests and the 10-year ISI
. program) is independent of the other and provides assurances of different plant characteristics.
The Type A tests assure the required leak-tightness for the reactor primary containment to demonstrate compliance with the guide'ines of 10 CFR Part 100. The 10-year ISI program provides assurance of the integtity of the plant's structures, systems, and components as well as verifying operational readiness of pumps and valves in compliance with 10 CFR 50.55a. There is no safety-related concern necessitating their coupling in the same refueling outage.
Based on the above, and because the proposed TS change is consistent with an NRC approved exemption, the staff finds this change acceptable.
TS 4.6.1.2.d The proposed change to SR 4.6.1.2.d adds a footnote "#" to document the NRS approval of a one-time partial exemption from Appendix J leak testing of the inclinedfueltransfersystem(IFTS)containmentpenetrationIMC-4untilthe fifth refueling outage.
As part of their letter dated April 16, 1993, the licensee requested a one-time partial exemption from the requirements of 10 CFR Part 50, Appendix J,.
Sections III.B.I.(b), III.B.3 and III.D.2.(a) for the Type B testing of the inclined fuel transfer system (IFTS) penetration IMC-4. The leakage rate for this penetration is required to be measured according to the method prescribed in 10 CFR Part 50, Appendix J, Section III.B.I.(b). The Type B test (s) shall be performed at least once every 24 months in accordance with Section III.D.2.(a), and the results shall be added to the combined leakage rate for all penetrations and valves subject to Type B and C tests to verify that the total combined leakage rate is less than the acceptance criteria identified in Section III.B.3. The licensee's proposal was for a one-time partial exemption, for CPS operating cycle 5, from the Type B testing requirements for the IFTS containment penetration as a result of the potential inability to perform a valid Type B local leak rate test (LLRT) on the penetration two-ply bellows assembly.
After completing a review of the facts provided in Information Notice 92-20,
" Inadequate Local Leak Rate Testing", issued on March 3, 1992, the licensee determined that there was only one bellows assembly at CPS used in a similar application, IFTS containment penetration IMC-4.
Due to the design and configuration of this containment penetration bellows assembly, the current method for performing Type B testing on the bellows assembly may have been inadequate. The possibility existed that separation of the two plies of the bellows may not have been sufficient to allow air flow to any crack locations such that the current method of performing the Type B test (pressurization between the two plies of the bellows) may not have challenged 100% of the area of the two-ply bellows constituting the containment barrier (s). The licensee i
stated that they were evaluating a number of options to provide a valid, reliable Type B test on the subject penetration.
These options included replacing the bellows assembly with one that could be tested in accordance i
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with 10 CFR Part 50, Appendix J, and developing an alternative means of I
testing the penetration which meets the requirements of Appendix J.
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j The licensee has investigated the option of replacing the bellows assembly.
l with one that can be tested in accordance with Appendix J.
The best design is one which can be installed without disassembling the IFTS tube and removing the upper pool shutoff valve (located just upstream of the blind flange to which the bellows assembly is attached). A bellows assembly design has besn identified which does not require any piping disassembly; however, the bellows j
would require an ASME "N" stamp and the lead time for procurement and fabrication is expected to be about one year.
Based on this lead time, it would not be possible to replace the bellows assembly during the next refueling outage; currently scheduled to begin in September 1993.
I Tho licensee is also evaluating the use of a special. test box which can bs<
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installed over the IFTS containment penetration bellows assembly to permit 1
performance of an acceptable local leak rate test (minimum pathway) of the s
i assembly. A vendor has been identified who can design and fabricate a test j
fixture for the testing of IMC-4. The box would be made in two or more pieces 4
of stainless steel and would be temporarily attached for the test and then removed upon completion. However, the box is very large-(46 inches inside diameter and 27.5 inches in height) and the probability of safely securing and making the box leak tight at the test pressure could prove to be difficult.
The licensee further stated that the work scope for the upcoming refueling i
outage had already been established and fixed. The impact to the outage schedule and the cost resulting from attempting to utilize a test box in i
testing the bellows assembly would be significant. Additional time would have
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to be scheduled for installation and removal of the test box. The potential i
radiation exposure associated with the test box installation and removal was also a consideration.
In addition, based on the uncertainties associated with the capabilities of the proposed test box, it was not clear that use of the test box would provide the most accurate or useful results.
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The licensee has decided that it would not be prudent to quickly implement j
either of the options described until an in-depth design review of the options 6
can be completed. This review would consider all aspects of the problem, i
including an evaluatton of the cost of replacement vice the risks of a j
temporary fix.
The proposed exemption would, therefore, provide the licensee l
with the time needed to complete a thorough review. Although the requested exemption would permit the licensee to not complete a valid Type B test of the IFTS penetration until the fifth refueling outage (RF-5), the licensee is confident that significant leakage from the bellows assembly can still be identified as discussed below.
l Until review of Information Notice 92-20, the licensee believed the design of the bellows assembly permitted Type B testing to be performed on the penetra-tion in compliance with the requirements of Appendix J.
Notwithstanding, the s
licensee believes the bellows assembly has shown to be acceptably leak tight i
and that significant degradation can continue to be detected by testing and inspection. A recent visual examination of the bellows assembly outer surface
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- was performed and no signs of degradation were found. - The last LLRT performed l
1 on containment penetration IMC-4 indicated a leakage of 21.36 secm. While the licensee recognizes that these test results may be questionable, they believe they reflect the relative leakage rate of the penetration.
ILRT test results to date have all been well within the acceptance criteria (axcept for a technical problem experienced during RF-3). During the next refueling outage, i
the licensee will continue to test the bellows assembly as previously tested, will maintain an acceptance criteria of less than 100 sccm per assembly and will perform a thorough examination of the outer bellows surface.
In addition, as a fins 1 assurance, the integrity of the bellows will be confirmed as part of the ILRT to be performed during the outage.
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The staff determined that the currently scheduled testing (both LLRT and ILRT), as well as the planned visual examination of the bellows assembly during the next refueling outage and the historically low associated teste leakage, provided sufficient justification to support a one-time partial exemption from the Type B testing requirements for containment penetration.
IMC-4 until the fifth refueling outage. Accordingly, the subject exemption was issued on Septeraber 7,1993.
1 Based on the above, and because the proposed TS change is consistent with an' NRC approved exemption, the staff finds this change acceptable.
Bases for TS 3/4.6.1.2 The licensee proposed changes to the Bases for TS 3/4.6.1.2 to reflect that CPS has been granted the partial exemptions from the requirements of 10 CFR Part 50, Appendix J, discussed above. Since these proposed Bases changes are consistent with the NRC approved exemptions and the propcsed changes to TS 3/4.6.1.2 described above, the staff finds them acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (58 FR 16864 and 58 FR 30197). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public' will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
R. Laufer D. Pickett e
Date: September 8, 1993 l
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