ML18100B025
| ML18100B025 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 04/15/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18100B024 | List: |
| References | |
| NUDOCS 9404220157 | |
| Download: ML18100B025 (8) | |
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I UNITED STATES NUCLEAR REGULATORY COMMISSION ENCLOSURE WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY-THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM REQUESTS FOR RELIEF PUBLIC SERVICE ELECTRIC AND GAS COMPANY SALEM GENERATING STATION. UNITS 1 AND 2 DOCKET NUMBERS 50-272 AND 50-311
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 alternatives have been authorized or relief has been requested by the licensee and granted by the Commission*
pursuant to Sections (a)(3)(i), (a)(3)(ii), or (f)(6)(i) of 10 CFR 50.55a.
In proposing alternatives or requesting relief, th~ licensee must demonstrate that:
(1) the proposed alternatives provide an acceptable level of quality and safety; (2) compliance 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 facility.
NRC guidance contained in Generic Letter (GL) 89-04, "Guidance on Developing Acceptable Inservice Testing Programs," provides alternatives to the Code requirements determined acceptable to the staff.
Section 10 CFR 50.55a authorizes the Commission to approve alternatives and to grant relief from ASME Code requirements upon making the necessary findings.
The NRC staff's findings with respect to authorizing alternatives and granting or not granting the rel*i~f requested as part of the litenSee's IST program are contained in this Safety Evaluation (SE).
In their.letter dated October 12, 1993, Public Service Electric and Gas Company (PSE&G) submitted a response to the anomalies identified in NRC's SE dated October 9, 1992.
2.0 CONCURRENT INTERVALS FOR UNITS 1 AND 2 In the October 1992 SE, the NRC noted that the interval dates for both units appeared to be the same (though each unit has a different date of commercial operation).
No explanation was included in the program submittal dated October 3, 1989.
The staff recommended that the interval dates be clarified.
In their letter, PSE&G indicated that in the original submittal of the second IO-year interval program (dated March 30, 1987), a request to place the two units on the same interval was included.
The request was not resubmitted in their October 3, 1989, response to NRC's Generic Letter 89-04 which transmitted the revised IST program document.
Because the request was included in the licensee's submittal prior to April 3, 1989, and did not 9404220157 940415
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' conflict with positions contained in Attachment 1 of GL 89-04, it was "approved" per GL 89-04.
However, the IST program document should clearly indicate the basis for approval and the fact that the units have been placed on concurrent intervals coincident with the commercial operation date of Unit 1.
No further NRC action is required at this time.
When the updated program for the third ten-year interval is developed, a paragraph stating and explaining the concurrent interval dates should be included for the variance from the requirements of 10 CFR 50.55a.
3.0 ACTIONS TO ADDRESS ANOMALIES In the Technical Evaluation Report attached to the NRC's SE issued October 9, 1992, 19 anomalies were identified that indicated certain action~ that the licensee should take to address concerns. The following table indicates the actions taken by the licensee.
Table 1 Actions Taken to Address Anomalies 1 - Relief requests for auxiliary feedwater pumps and boric acid transfer pumps may be withdrawn if new instrumentation has been installed.
2 - For the chilled water pumps, develop and provide information to show the requested relief adequately addresses pump operational readiness or provide a reasonable alternative to the Code~
3 - For the Unit 2 service water pumps, pursue the installation of adequate flow instrumentation or other means of testing or provide additional information to support current relief re uest.
4 - Test supervisors for safety and relief valve testing must meet the ualifications of ASME PTC 25.3.
New flow instrumentation has been installed and relief is no longer required.
The relief request has been withdrawn.
See Section 4.0 below for evaluation of the revised relief.
A new test loop was installed which includes instrumentation that meets the accuracy requirements of the Code.
The relief request has been withdrawn.
See Section 5.0 below for evaluation of the revised relief.
5 - For SJ44, containment sump suction valves, relief was granted to observe remote position indication every other refueling provided the test is performed whenever manways for the containment sum are removed.
6 - For SJ55, accumulator discharge check valves, a full-stroke exercise during refueling outages was approved provided the licensee investigate the practicality of performing a part-stroke exercise during cold shutdown and either implement the part-stroke exercise or include the results of the investigation in the IST program.
7 - For PR25, emergency core cooling system discharge relief check valves, relief was granted per GL 89-04, Position 2, to part-stroke -
exercise quarterly and to use disassembly and inspection for full-stroke exercising, with a provision that post-maintenance be performed on the valves foll owi n reas*sembly.
8 - For the reactor head vent valves, the relief request did not contain adequate justification for not performing testing on a cold-shutdown frequency.
Relief was denied.
The remote position verification has been added as a *requirement whenever the manways are opened. Therefore, the provisions of the relief granted
_in the October 1992 SE have been addressed.
The licensee indicates that these valves cannot be part-stroke exercised d~ring cold shutdown.
The motor-operated isolation valves {one per accumulator} cannot be partially stroked, but must complete a full stroke before changing direction.
This could cause a complete discharge of the water volume in the accumulator and possibly inject nitrogen into the reactor coolant system, causing gas binding of the residual heat removal pumps and a subsequent loss of shutdown cooling.
Such an event occurred previously at Salem Unit I LER 50-272/89-019.
A part-stroke exercise has been specifie~ as a required post-maintenance test after the periodic disassembly and inspection.
The reactor head vent valves are tested on a cold-shutdown frequency.
Acoustic monitoring is used to satisfy the requirements for stroke time and remote position indication of the valves. Relief is not required to perform testing on a
~old-shutdown frequency because deferral is allowed by the ASME Code.
- 9 - For SJ3, charging pump suction valves from the refueling water storage tank, interim relief was granted to defer testing to refueling outages.
However, the impracticality or hardship of exercising the valves during cold shutdown was not discussed in the relief re uest.
10 - For the service water supply to turbine generator check valves, relief was granted per GL 89-04, Position 2, to use disassembly and inspection to full-stroke exercise the valves, provided a post-maintenance test is performed followin reassembly.
11 - For the service water supply to the nuclear header check valves, relief was granted per GL 89-04, Position 2, to use disassembly and inspection to full-stroke exercise the valves, provided a post-maintenance test is performed followin reassembly.
12 - The relief requests in the licensee's submittal did not have unique identifiers, such as numbers, other than by valve numbers.
It was recommended that future revisions include unique identification of the relief requests.
13 - For the emergency core cooling system injection check valves, the relief request addressed only the opening safety function.
It was not clear that the "close" safety function and required leak testing were addressed.
14 - Relief requests that are actually cold shutdown justifications should be identified as such.
Cold shutdown testing is allowed by the Code and relief is not re uired.
These valves will be tested on a cold shutdown frequency.
The relief request has bee~ withdrawn.
Post-maintenance testing requirements have been identified in the appropriate maintenance department procedure.
Post-maintenance testing requirements have been identified in1 the appropriate maintenance department procedure.
Future IST submittals will contain unique identifiers for relief requests. Current relief requests are identified by component numbers.
The changes are not practical for the current interval, but will be made for the next ten-year updated ro ram..
Each of the valves are tested in the closed direction on a cold-shutdown frequency and leakrate tested every two years, as required, except for valves 1SJ70 and 2SJ70.
See Section
. 6.0 for evaluation of the revised relief re uest.
PSE&G will not seek relief in future submittals for cold shutdown testing. The justifications for cold shutdown testing will be included in the IST program.
15 - For valves that cannot be tested during power operations, evaluate all requests to ensure adequate bases has been provided to justify testing of valves at a frequency other than cold shutdown or test valves on a cold shutdown fre uency.
16 :... For the diesel generator fuel oil engine driven booster pumps, the Unit 2 relief request appears to be missing information. It was assumed to be the same as Unit l's request.
The Unit 2 relief request should be revised during future updates to the ro ram.
17 - The program should include a discussion of the development process for the IST program such as a listing of documents used, method of component selection, basis for testing required, basis for categorizing valves, and method used to maintain the ro ram current.
18 - The proposed frequency for testing VC2 and VC3, containment purge isolation valves, was unclear*
and inconsistent between the units.
19 - The proposed frequency for testing VC I *and VC4, containment ur e isolation valves, was unclear.
5 -
The licensee indicates that all valves that cannot be tested at power are either being tested on a cold shutdown frequency or justification has been_provided to test at an alternate frequency.
The Unit 2 relief request was missing information as assumed and it was intended to be the same as the Unit I relief request. The text will be corrected in the next submittal.
The process~was described in an attachment to the October 12, 1993, letter. The process appears to be adequate to maintain the program scope and. testing requirements.
These valves will be tested on a cold shutdown frequency.
The relief request is withdrawn.
These valves will be tested on a cold shutdown frequency.
The relief re uest is withdrawn.
4.0 CHILLED WATER PUMPS RELIEF REQUEST*
The licensee has -requested relief from the ASME Code requirements that flow instruments be accurate to 2% over the full-scale range of the instrument and that the range be three times the reference value or less. Interim relief was granted in the NRC's SE issued October 9, 1992, to use existing instrumenta-tion, but indicated that the licensee needed to include additional information in the relief request to support long-term relief.
4.1 Licensee's Basis for Relief The licensee states:
The installed flow measurement instrumentation is calibrated to an inaccuracy of 3% which is the design limit of these Fischer-Porter Rotometers.
The ASME Code requirement is 2% inaccuracy and a range of no greater than three times expected flow.
PSE&G's instrumentation inaccuracy exceeds the Code by 50%.
However, the range of these instruments is 0-400 GPM, while the code allowed range would be 0-1110 GPM.
Since our expected full-scale range used for testing is approximately 36% of that allowed by the Code, the combination of the full-scale range and accuracy of the installed instrumentation is equal to or more conservative than the Code requires.
In addition, the test flow rate specified in the test procedure is the QY.!!1Q. design flow.
This flow is 18%
greater than the system design flow requirements.
Assuming the inaccuracy from the flow meter would result in the excess flow margin being approximately 17%.
The reduction in flow margin will not impact the ability of the pumps to perform the required safety function.
The station calibration program is utilized to maintain instrument accuracy in accordance with the requirements of paragraph IWP-4140.
4.2 Proposed Alternative The licensee proposes to use the installed flow instrumentation which provides a reading within the reading which would be achieved if the range and accuracy requirements of the Code were met.
4.3 Evaluation The staff has determined that for analog instruments that yield a reading that is at least equivalent to the reading that would be achieved from instruments that meet the Code requirements, it is an undue hardship to require licensees to replace permanently installed instruments as no compensating increase in quality and safety would ensue.
The reading of the instrument that is used to monitor the chilled water pumps is more conservative than would be achieved with instruments which*were accurate to within 2%, with a full-scale range of three times the reference value.
If new instruments are purchased, the accuracy requirements of the Code must be met.
While the fact that the test flow rate is greater than the system flow requirements, inservice testing is based on the component and not the system.
Even if margin exists for the pump, the Code requirements are intended to monitor for degrading conditions. Margin in the system flow requirements allows the licensee to evaluate degradation of the pump to determine if it is capable of performing its safety function of providing a certain minimum flow, and, if necessary, to adjust reference values.
In Section XI Interpretation XI-1-79-19, the Code committee clarified the intent of the inservice testing
\\. ranges, stating that the limits within each of these ranges refer to the pump and not to the system. That is, the ranges are for the pump test data. If the ranges cannot*
1be :met, the Owner may specify new ref e.rence values *or new ranges (per IWP-3210) if it can show that the overall pump performance has not degraded from its intended function.
4.4 Conclusion The alternative of using installed flow instruments for measuring flow of the chilled water pumps is authorized pursuant to 10 CFR 50.55a(a)(3)(ii). The approval is based on the hardship that would result if the licensee were required to replace the instruments which* provide readings within the accuracy that would be achieved with instruments meeting the Code accuracy and range requirements. Thus, the hardship of compliance with the Code would not be accompanied by a compensating increase in quality and safety.
5.0 RELIEF FOR TEST SUPERVISOR QUALIFICATIONS The 1983 Edition, with Summer 1983 Addenda, specifies that safety valve and relief valve set point shall be tested in accordance with ASME Performance Test Code (PTC) 25~J-1976. Paragraph 3.02 of PTC 25.3-1976 specifies the qualifications for the person supervising the testing as having obtained a degree in a branch of engineering and having at least two years practical experience in fluid-flow measurement.
The licensee proposes to use the 1977 Addenda to PTC 25.3-1976.
5.1 Licensee's Basis for Relief The licensee stated that the "Salem Maintenance Department has incorporated the requirements of Section 3.02 of PTC 25.3-1976 September 1977 Addendum into the qualification requirements for test supervisors of relief valve testing."
5.2 Proposed Alternative The 1977 Addendum to PTC 25.3-1976 includes revised wording for Paragraph 3.02 to specify that a person who supervises the test* shall have a formal education in thermodynamics and fluid mechanics, at least two years practical experience in fluid flow measurement~ and experience in test supervision.
5.3 Evaluation The ASME Code committee issued Code Case N-442 on February 23, 1987, which states that "[i]t is the opinion of the Committee that the 1977 Addendum may be included in all references to ANSI/ASME PTC 25.3-1976 in Section III, Division 1, Subsections NB, NC, ND, and NE."
The code case did not address the acceptability of using the addendum for Section XI.
However, responding to inquiry number IN-92-027, the ASME Code Committee,Section XI, stated that, although the test supervisor's qualifications of ASME PTC 25.3-1976, paragraph 3.02, apply when performing set point testing in accordance with Section XI, IWV-3512, the provisions stated in PTC 25.3-1976, paragraph 3.02, are
.. permissive (allow discretion). Therefore, the guidance for test supervisor qual i fi cation jn Cpde, Cas~)N-::H~!* is, an. ~qceptap~~ iiJ ~EffQat i y~: to.Section XI inservice testing requirements as well asSection III des*ign capacity verification.. The alternative provides an acceptable,Jev.el of quality and safety for assuring the operational readiness of the safety and relief valves.
5.4 Conclusion The alternative to use the 1977 Add~~dum to-PTC 25~3-i976 is authorized pursuant to 10 CFR 50.55a(a)(3)(i) based on the alternative providing an acceptable level of quality and safety.
6.0 CONCLUSION
The staff concludes that the licensee has taken appropriate actions to address the anomalies identified in the NRC Safety Evaluation issued October 9~ 1992, and that the revised relief requests pro.vide reasonable assurance of the operational readiness of the pumps and valves to perform their ~afetY-related fonctions.
Pursuant to 10 CFR 50.55a(a)(3)(i) and (a)(3)(ii), the staff has~
determined that the proposed alternatives are authorized because (1) the alternative provides an acceptable level of qu,ali,ty and safety or (2),.
compliance with the Code will result in a hardsh.ipor unusual difficulty without a compensating increase in the level of quality and safety.
Principal Contributor:
P. Campbell Date: April 15, 1994