ML17335A451
| ML17335A451 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/29/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17335A450 | List: |
| References | |
| NUDOCS 9901060094 | |
| Download: ML17335A451 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.c. 205554001 SAFETY EVALUATIONBYTHE OFFICE OF NUCLEAR REACTOR REGULATION RELATEDTO EVALUATIONOF RE UESTS FOR RELIEF ASSOCIATED WITHTHE INSERVICE TESTING PROGRAM INDIANAMICHIGANPOWER COMPANY DONALDC. COOK NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-315 AND 50-316
1.0 INTRODUCTION
The Code of Federal Regulations, 10 CFR 50.55a, requires that inservice testing (IST) of certain ASME Code Class 1, 2, and 3 pumps and valves be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda, except where relief has been requested and granted or proposed alternatives have been authorized by the Commission pursuant to 10 CFR 50.55a (f)(6)(i), (a)(3)(i), or (a)(3)(ii). In order to obtain authorization or relief, the licensee must demonstrate that: (1) conformance is impractical for its facility; (2) the proposed alternative provides an acceptable level of quality and safety; or (3) compliance would result in a hardship or unusual difficultywithout a compensating increase in the level of quality and safety.
Section 50.55a (f)(4)(iv) provides that inservice tests of pumps and valves may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and modifications listed, and subject to Commission approval.
NRC guidance contained in Generic Letter (GL) 89-04, "Guidance on Developing Acceptable lnservice Testing Programs," provided alternatives to the Code requirements determined to be acceptable to the staff and authorized the use of the alternatives in Positions 1, 2, 6, 7, 9, and 10 provided the licensee follows the guidance delineated in the applicable position. When an alternative is proposed which is in accordance with GL 89-04 guidance and is documented in the IST program, no further evaluation is required; however, implementation of the alternative is subject to NRC inspection.
Section 50.55a authorizes the Commission to grant relief from ASME Code requirements or to approve proposed alternatives upon making the necessary findings. The NRC staffs findings with respect to granting or not granting the relief requested or authorizing the proposed alternative as part of the licensee's IST program are contained in this Safety Evaluation (SE).
The third 10-year IST interval for the Donald C. Cook Nuclear Plant, Units 1 and 2, began on July 1, 1996, and ends on June 30, 2006. The IST program was developed in accordance with the 1989 edition of the ASME Section XI Code which incorporates Operations and Maintenance (OM) Standards Part 1 (CM-1), Part 6 (OM-6), and Part 10 (OM-10), for IST of safety and relief devices, pumps, and valves, respectively.
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2.0 BACKGROUND
Relief requests submitted in accordance with the regulations were evaluated by the NRC for the licensee's third 10-year interval IST program and the results were transmitted to the licensee in a letter dated May 27, 1997. Relief Request P-2 for measuring the vibration of the boric acid transfer pumps was granted on an interim basis in the May 27, 1997, SE for a period of 90 days to allow the licensee time to further review the impact of not taking axial vibration measurements.
The licensee provided additional information in a letter dated August 19, 1997.
The staff had a phone conversation with the licensee on January 13, 1998, to discuss the revised relief request.
The licensee issued a second revision to this relief request in a letter dated March 26, 1998.
Relief Request Number 2 is evaluated in Section 3.0 of this SE.
The May 27, 1997, SE also included two valve relief requests, REL-12 and REL-13. The first was partially denied.
In response to the second, the staff requested the licensee to supply additional information as to the impracticality of performing the required Code testing.
Both valve relief requests are addressed in Section 4.0 of this SE.
3.0 PUMP RELIEF RE VEST 3.1 Relief Re uest Number 2 The licensee has requested relief from the vibration measurement requirements of OM-6, Paragraph 4.6.4(a), for the boric acid transfer pumps in Unit 1 (1-PP-46-1 and 1-PP-46-2) and Unit 2 (2-PP-46-3 and 2-PPA64). The licensee has proposed to take axial vibration measurements on the outboard motor bearing for all four pumps.
3.1.1 Licensee's Basis for Re uestin Relief The licensee states:
By design, the only accessible point for taking axial vibration measurements is the outboard motor bearing.
It is unsafe to monitor the axial direction vibration on the inboard pump bearing due to the proximity of the rotating shaft, and there is no position for monitoring the outboard pump bearing housing because of the presence of heat tracing. Modifications to the coupling shield to allow access were attempted.
- However, the modified shield did not provide sufficient clearance to allow individuals performing the measurement to safely place their hands near the rotating shaft.
3.1.2 A~i The licensee proposes:
Axial vibration willbe measured at the outboard motor bearing. The vibration limits contained in ASME OMa-1988, Part 6, Table 3[a], willbe applied to the vibration levels monitored at the outboard motor bearing.
The measurements taken in the axial direction at the outboard motor bearing willbe representative of the pump's axial vibration because the axial motion willoriginate at the pump.
3.1.3 Evaluation The boric acid transfer pumps have a safety requirement to pump a boric acid solution from the boric acid storage tank to the suction of the charging pumps.
The Code requires that vibration measurements for centrifugal pumps be taken in two orthogonal directions on each accessible pump bearing housing and in the axial direction on each accessible pump thrust bearing housing. The licensee states that access to the thrust bearing housing is impeded by a coupling guard and thermal insulation. Attempts to modify the pump to allow axial vibration measurement of the thrust bearing housing have not been successful.
The licensee proposes to take the axial vibration measurement on the outboard motor bearing and apply the vibration ranges given in Table 3a of OM-6. Although the axial vibration measurement would now include noise from the motor, that contribution should be minimal considering that the pump is directly coupled to'the motor and all significant axial contributors to vibration should originate from'the pump. Therefore, the proposed location to take axial vibration measurements, coupled with continued use of the vibration ranges given in Table 3a of OM-6, provide an acceptable level of quality and safety.
3.1.4 Conclusion The proposed alternative to the vibration measurement requirements of OM-6, Paragraph 4.6.4(a), for the boric acid transfer pumps in Unit 1 (1-PP-46-1 and 1-PP46-2) and Unit 2 (2PP-46-3 and 2-PP464) is authorized pursuant to 10 CFR 50.55a(a)(3)(i) based on the alternative providing an acceptable level of quality and safety.
4.0 VALVERELIEF RE UESTS 4.1 Relief Re uest REL-12 The licensee's proposed alternative to perform check valve disassembly and inspection for, SI-189, the check valve in the safety valve discharge header to the pressurizer relief tank, every third refueling outage was denied in the staffs SE dated May 27, 1997.
It is impractical to test this valve in accordance with the Code requirements because isolation of this valve would isolate the safety relief valve discharge headers in a number of safety-related systems and the affected system would have to be redesigned or replaced to allow the testing in an acceptable manner.
In the licensee's submittal dated August 19, 1998, the licensee stated that this valve is partial-stroke exercised during cold shutdowns and disassembled and inspected every refueling outage.
The licensee's proposed testing is in accordance with the guidance in GL 89-04, Position 2, and provides a reasonable assurance of operational readiness.
Therefore, relief is granted pursuant to 10 CFR 50.55a(f)(6)(i).
-4 4.2 Relief Re uest REL-13 This relief request was granted for the chemical volume and control system check valves CS-328L1, CS-328L4, CS-329L1, and CS-329L4, in the staff's SE dated May 27, 1997. The licensee was requested to provide additional information to support the impracticality of testing these valves in accordance with the Code requirements.
The licensee stated in their submittal dated August 19, 1998, that these check valves have no external position indication or means of exercising and are located inside the crane wall in the reactor containment.
The licensee also stated that no instrumentation exists upstream of the valve that can be used to show the valve disk returns to the fullyclosed position after exercising.
This additional justification confirms the impracticality of testing these valves in accordance with the Code requirements.
The licensee has committed to disassemble and inspect these valves in accordance with GL 89-04, Position
- 2. Therefore, no further evaluation is necessary.
5.0 CONCLUSION
The staff has concluded that the relief requests willprovide reasonable assurance of operational readiness of the referenced pumps and valves in the IST program.
For Relief Request P-2, the staff has authorized alternatives pursuant to 10 CFR 50.55a(a)(3)(i) in that it provides an acceptable level of quality and safety. The staff has determined that granting relief requests alternatives pursuant to Sections (f)(6)(i) of 10 CFR 50.55a is authorized by law and willnot endanger life or property, or the common defense and security, and is otherwise in the public interest.
In making a determination of impracticality, the staff has considered the burden on the licensee ifthe requirements were imposed.
Principal Contributor: J. Colaccino pate December 29, 1998
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