ML19340B717
| ML19340B717 | |
| Person / Time | |
|---|---|
| Issue date: | 08/31/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19340B716 | List: |
| References | |
| NUDOCS 8011110754 | |
| Download: ML19340B717 (18) | |
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TOPICAL REPORT EVALUATION i
REPORT TITLE. Assessment of Reactor Internals Vibration in BWR/4 and BWR/5 Plants ORIGINATING The General Electric Company REPORT NO.:
NEDE-24057, November, 1977 NEDE-24057-1 (Amendment No. 1), December, 1978 NEDE-24057-2 (Amendment No. 2), June, 1979 REVIEWED BY: Mechanical Engineering Branch Division of Engineering Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission August, 1980 J
INTRODUCTION 1
The structural components inside a reactor are called reactor internals. Reactor internals are important to safety and should be designed to cope with loads resulting from potential seismic events, postulated pipe break events, in addition to loads resulting from normal plant operations and anticipated opera-tional occurrences.
In addition to certain optional surveillance programs such i
as loose parts monitoring and core barrel motion monitoring, reactor internals are subjected to a comprehensive vibration assessment program which includes preoperational and initial startup flow testing.
'l Based on the recommendations of Regulatory Guide 1.20, for the first-of-a-kind prototype reactor, the vibration assessment program includes pre-test analysis for vibration predictions, vibration monitoring during the flow testing, and the post-test inspection of reactor internals. The purpose is to verify structural integrity prior to commercial operation for steady. state and transient flow induced vibratory loads. Thu non-prototype reactor which is similar to the prototype, may have part of the program requirements reduced, dependent upon the degree of design similarity. Additional requirements may be needed if design modifications in the non-prototype are intended to resolve some identified operating problems. Purtharmore, BWR test program requirements differ from PWRs due to the difficulty of conducting a hot flow test prior to fuel loading and in performing an inspection after the completion of the startup hot testing following fuel loading. An option which has evolved for BWR's is to conduct an incpection after the equivalent cold flow testing and to perform additional vibration monitoring during the subsequent precritical and startup phases of the hot flow testing.
SUMMARY
OF TOPICAL REPORT NEDE-24057 -provides an overview of current and future vibration assessment programs for BWR/4 and BWR/5 internals. Descriptions in the report include 8011110 4
. the vibration prediction methodology used; the sensor types and locations in the several plants having vibration tests conducted; the scope and objectives of the internals inspection program; typical test results from vibration measurement sensors and the internals inspection; the general vibration characteristics of various components and assemblies; analytical basis for the test acceptance criteria, and comparisons of some predicted cad measured vibration amplitudes.
Conclusions of NEDE-24057 may be summarized briefly as the following:
A.
Based on satisfactory test results and operating records of 11 BWR/4 plants, valid prototypes were established for reactor internals of vessel sizes 183, 218, and 251 inches.
The plants are Duane Arnold, Fitzpatrick, and r
Browns Ferry 1 respectively.
B.
Vibration measurements are planned in the lead BWR/5 plants to evaluate the jet pumps, which differ from the BWR/4 jet pumps. Measurements are also planned for the BWR/4 - 201" size prototype, the Chinshan 1 plant in Taiwan, China.
C.
The Tokai 2 plant in Japan has been established as the BWR/5 - 251" size prototype based on satisfactory test results.
D.
BWR/4 or BWR/5 plants having internals similar to the above mentioned prototype plants have been designated to conduct non-prototype test programs as characterized by Regulatory Guide 1.20.
E.
Vibration problems encountered in BWR/4 plants with feedwater spargers and incore instrument tubes have been resolved by design modifications which were developed in flow test facilities and subsequently confirmed through in plant testing.
In conclusion, the General Electric Ccmpany has proposed that the vibration assessment programs presented in NECE-24057 meet the requirements of Regulatory Guide 1.20.
They claim that the satisfactory test results, the record of 11 operating plants, and the planned vibration assessment progra provide the needed assurance that the design of BWR/4 and BWR/5 internals is adequate to withstand flow induced vibration resulting from normal plant operations and anticipated operational occurrences.
SDefARY OF STAFF EVALUATION A.
Objectives of Staff Review:
i NEDE-24057 was evaluated emphasizing:
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(1) Whether the completed or planned vibration assessment programs presented in NEDE-24057 meet the intent of Regulatory Guide 1.20.
. (2) Whether any experienced operating problems have been resolved, or acceptable measures for resolution have been proposed in NEDE-24057.
B.
Staff Evaluation and
Conclusions:
(1)
T'ae adequacy of the vibration assessment programs and test results were evaluated for the various size BWR/4 prototype Laternals. The prototypes include the 251" size Browns Ferry 1, the 218" size Fitzpatrick, and the 183".1ze Duane Arnold. Vibration was measured during the preoperational, precritical and startup flow tests. The internals were visually inspected after the preoperational tests.
The staff evaluation has concluded that the overall vibration assees-ment programs are adequate and the test and inspection results are satisfactory.
(2) The acceptability of inspection of internals conducted immediately following the preoperational testing was investigated. The concern is that such a test is conducted during cold flow conditions without fuel. NEDE-24057 indicated that vibration maplitudes are consistentIv and substantially higher during cold flow preoperational test conditions as compared to start up and normal operating conditions conducted hot, following fuel loading. Based on additional detailed test data from the Fitzpatrick test (topical report NEDE-23673) regarding vibration at the shroud head assemblies, we have concluded that inspection of internals immediately following the completion of preoperational test 4
la acceptable, provided the recirculation system was operated at flow rates up to and exceeding the rated mass flow for normal operation, which was the case in all of the three above prototype tcsts.
(3) Inspection of the steam dryer assemblies conducted after the preoperational cold flow testing was questioned, since the effects of an actual vibration anvironment with hot steam were not simulated during the test. The s'.eam dryer assemblies were not instrumented, hence any vibration which occurred during start up hot testing was not measured. However, the steam dryer vane assemblies were qualified via a combination of labo-ratory vibration testing and analysis. Based on the foregoing investi-gation and the satisfactory histcry of operation in operating BWR's, we have concluded that the steam dryer assemblies are adequate to sustain flow induced vibration expected in service.
(4) We have investigated the accessibility of BWR internals for inspection after the preoperational test, especially the clearance between jet pumps and the size of opening at the shroud base plate and supports.
We have cor :1uded that the accessibility for inspection is acceptable.
(5) We have evaluated the acceptability of the vibration assessment programs for non-prototype BWR/4 internals. For those plants which are closely similar to the prototypes identified in item (1) above. Comfirmatory tests consisting only of non-instrumented preoperational testing and
' subsequent inspection of the internals are acceptable. This acceptance l
'is based on the discussion in item (2) above, and the acceptable option
. permitted by Regulatory Guide 1.20 for BWR plants. BWR/4 plants in this category include the 218" size in Hatch 2 and Shorehem, and the 251" size in Susquehanna 1 and 2, Hope Creek 1 and 2. and Fermi 2 plants.
(6)
In lieu of conducting confirmatory tests consisting of a non-instrumented preoperational test with subsequent inspe: tion, another option provided in Regulatory Guide 1.20 for BWR non-prototype internals is to conduct a confirmatory test without inspection but with instrumented vibration monitoring during the hot start-up test to ensure that the measured internals vibration is similar in nature and comparable in amplitude to those in the designated prototype internals. We have evaluated the program using this option presented for the internals of the 218" size in Cooper, Hatch 1, Brunswick 1 and 2 planer, and the 251" size in Browns Ferry 2 and 3, and Peach Botton 2 and 3 plas.ts. We have concluded that the presented programs are acceptable.
(7) NEDE-24057 indicated that the Chinshan 1 plant in Taiwan, China was designated as the plant for the BWR/4-201" size prototype internals.
Since the test results are not yet available for staff review, we are unable to conclude that the internals of the chinshan 1 may be referenced at this time as the valid prototype for other plant licensing applications.
(8) For BWR/5 internals, NEDE-24057 indicated that the vibration assessment program was ccepleted in the Tokai-2 plant in Japan for the BWR/5-218" size prototype. We have evaluated the vibration assessment prcgram and test and inspection results of Tokai 2.
Since the Tokai 2 internals are generally similar to the Browns Ferry 1, a BWR/4-251" prototype excent for the design of the jet pumps, vibrations measurements at Tokai-2 we e concentrated at the jet pumps and at the shroud head upper bolt guide ring. These locations were selected since they would indicate the effect of jet pump motion and overall shroud motion. We have concluded that the program, the test results and the inspection results of the Tokai 2 internals are acceptable. Programs are also presented for the Zimmer plant for the BWR/5-218" size internals, and for the Bailly plant for the BWR/5-201" size internals. Since the internals in Zimmer are generally similar to the BWR/4-218" size prototype in Fitzpatrick, similar to the case of Tokai 2 and its BWR/4-251" counterpart, a vibration assessment program having all the major elements as the Takai 2 program is acceptable for qualifying the Zimmer internals as the 218" size pro to type. As for the internals in Bailly, a similarly constructed program as for Tokai 2 is acceptable only if the program and test resule.
of the Chinshan internals, BWR/4-201" size prototype, becomes available and is accepted by the NRC. In lieu of this, additional measurements comparable to the BWR/4 prototype programs may be implemented for qualifying Bailly internals as the prototype of the BWR/5-201" size internals.
(9) NEDE-24057 indicated that LaSalle 1 (a BWR/5-251") will have an internal vibration assessment program with vibration measurements of the jet pumps during preoperational, precritical and startup tests, and inspection following the preoperational testing. Since the LaSalle 1 internals are
. similar to the internals of Tokai 2, the BWR/5-251" prototype, except for differences in the jet pump adaptor design, we have concluded that the proposed program is acceptable and will consider LaSalle 1 as an non-prototype category II plant.
(10) NEDE-24057 indicated that the vibration assessment program for WPPSS-2 internals (a BUR /5-251") will have an instrumented confirmatory test during startup and will not have preoperational flow test and inspection.
Areas of the jet pumps and the shroud head upper guide ring will be instrumented. The report also indicated that the programs for non-prototype LaSalle 2 and Nine Mile Point 2 internals will have non-instrumented preoperational test and subsequent inspections. These proposed programs are consistent with the treatment of non-prototype BWR/4 internals and meet the intent and acceptable options available in Regulatory Guide 1.20 as discussed in item (5) and (6) above. We conclude that the proposed confirmatory test program are acceptable.
(11) We have evaluated the effects of problems experienced in the BWR internals of operating plants, some of which include in-core channel box wear, feedwater sparger failure and the failure of jet pump holddown beam bar (HDBB). Generic review of the channel box and sparger problems have been conpleted by the staff. The design modifications which have been implemented in operating BWR plants and in plants under licensing appli-cation have been acceptably covered in NEDE-24057. The jet pump EDB" failure occurred in BWR/3 plants and was caused by progressive inter-granular stress corrosion. This is a long duration process similar to the sparger and channel box problems which is beyond the scope of the assessment programs of Regulatory Guide 1.20.
The on-going short term staff action for the jet pump EDBB includes degradation surveillance and replacement of the failed EDBB during a planned plant fuel outage.
Permanent resolution of this problem is expected prior to the issuance of an operating license for any plant included in NEDE-24057.
REGULATORY POSITIONS The staff, based on evaluation of GE topical report NEDE-24057, has concluded the following relative to the preoperational and startup vibration assessment and testing program for GE BWR/4 and BWR/5 internals:
A.
Valid prototype internals are established for the plants listed in Table 1.
These plants have satisfactorily completed the vibration assessment program in compliance with the Regulatory Guide 1.20:
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i Table 1 Valid Prototypes - Operating Plant Name Valid Prototype Internals Type and Size Browns Ferry l' Bhi/4-251" Fitzpatrick Bhi/4-218" Duane Arnold BWR/4-183" Tokai 2 Bhi/5-251" The Prototype internals in Table 1 are acceptable to be referenced in the plant licensing applications.
i B.
The plants listed in Tables 2 and 3 below having reactor internals substan-tially similar to their individually referenced valid prototype are acceptable to be designated as Non-prototype Category I n accordance with Regulatory Guide 1.20:
l Table 2 Non-Prototype, Category I - Operating Plz, t Name Reactor Type Plant with designated
& Size prototype internals Browns Ferry 2 & 3 BWR/4-251" Browns Ferry 1 Peach Bottom 2 & 3 BWR/4-251" Browns Ferry 1 1
Cooper BWR/4-218" Fitzpatrick Hatch 1 & 2 BWR/4-218" Fitzpatrick Brunswick 1 & 2 BWR/4-218" Fitzpatrick I
-7 Table 3 Non-Prototype, Category I - Under Construction Plant Name Reactor Type Plant with designated
& Size Valid Prototype internals Susquehann 1 & 2 BWR/4-251" Browns Ferry 1 Hope Creek 1 & 2 BWR/4-251" Browns Ferry 1 Limerick 1 & 2 BWR/4-251" Browns Ferry 1 Fermi 2 BWR/4-251" Browns Ferry 1 Shoreham BWR/4-218" Fitzpatrick LaSalle 2 BWR/5-251" Tokai 2/LaSalle 1 WDPSS 2 BWR/5-251" Tokai 2 Nine Mile Point 2 BWR/5-251" Tokai 2 The vibration assessment Programs presented in NEDE-24057 for plants in Tables 2 and 3 are acceptable. Acceptability of the non-prototype program implementation is contingent upon NRC review on a case by case basis of the test and inspection results.
C.
The BWR/S internals in the Bailly and Zi=mer plants should be designated as the prototypes for sizes 201" and 218" respectively. The vibration assessment program presented in the report for Zimmer is acceptable. The program for Bailly should be revised to include additional measurements pending the availability of test results of Chinshan internals in Taiwan, China, as previously discussed. Acceptability of establishing the Bailly and Zimmer internals as valid prototypes is contingent upon review by the staff of the results of the programs for each plant.
Table 4 i
Prototype - Under Construction Plant Name Internals Type & Size Bailly BWR/5-201" Zimmer BWR/5-218" Chinshan BWR/4-201" l
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E. The BWR/5 internals in LaSalle 1 plant are acceptable to be designeted as Non-prototype Category II in accordance vith Regulatory Guide 1.20.
The vibration assessment program present n Amendment No. 2 of NEDE-24057 for LaSalle 1 is 2cceptable. Acceptabi;..j of LaSalle 1 as a Non-Prototype Category II plant is contingent upon NRC review of the test and inspection results after the completion of the program.
Table 5 4
Non-Prototype, Category II Under Construction Plant Name Reactor Type Plant with designated
& Size valid prototype internals s
LaSalle 1 BWR/5-251" Tokai 2 F.
The resolution of IE Bulletin 80-07 concerning the observed cracking of jet pump holddown beams should be considered an open issue in the operating license review of all BWR plants. Each plant should document its proposed action ta resolve the problem prior to the issuance of an operating license 1
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