ML20215F450
| ML20215F450 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/18/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215F433 | List: |
| References | |
| GL-83-28, NUDOCS 8612230401 | |
| Download: ML20215F450 (7) | |
Text
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6 ENCLOSURE SAFETY EVALUATION FOR GENERIC LETTER 83-28. ITEMS 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1. AND 4.5.1 SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328
. I.
INTRODUCTION In February 1983, the Salem Nuclear Power Station experienced two failures of the reactor trip system upon the receipt of trip signals. These failures were attributed to Westinghouse - Type DB-50 reactor trip system (RTS) circuit breakers. The failures at Salem on February 22 and 25,1983, were believed to have been caused by a binding action within the undervoltage trip attachment (UVTA) located inside the breaker cubicle. Due to problems with the circuit breakers at Salem and at other plants, NRC. issued Generic letter 83-28 Required Actions Based on Generic Implications of Salem Anticipated Transient Without Scram (ATWS) Events, dated July 8,1983. This letter described intermediate-term actions to be taken by licensees and applicants as a result of the Salem anticipated transient without scram events.
These actions were developed by the staff based on information contained. in NUREG-1000, Generic Implications of ATWS Events at the Salem Nuclear Power Plant.
Actions to be performed included development of programs to provide for post trip review, classification of equipment, vendor interface, post-maintenance testing, and RTS reliability improve-ments. The Generic Letter stated that for Action Items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1, and 4.5.1 NRC Regional Offices would perform a post-imple-mentation review and issue Safety Evaluation Reports.
This report is the Regional Safety Evaluation of Tennessee Valley Authority's submittal dated November 7,1983 to Generic Letter 83-28 for Sequoyah Units 1 and 2.
i II.
REVIEW GUIDELINES The licensee's responses were evaluated for compliance to the staff posi-tions delineated in Generic Letter 83-28 for Action Items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1, and 4.5.1.
The requirements of the above action items, as described in the Generic Letter, are paraphrased below:
i 3.1 Post-Maintenance Testing (Reactor Trip System Components)
Position
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The following actions are applicable to post-maintenance testing:
1.
Licensees and applicants shall submit the results of their review of test and maintenance procedures and Technical Specifications to assure that post-maintenancs operability testing of safety-related components in the reactor trip system is required to be conducted 8612230401 B61218 DR ADOCK 05000327 p
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and that the testing demonstrates that the equipment is capable of performing its safety functions before being returned to service.
2.
Licensees and applicants shall submit the results ofgtheir check of vendor and engineering recomendations to ensurf that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications, where required.
3.2 Post-Maintenance Testing (All Other Safety-Related Components)
Position The following actions are applicable to post-maintenance testing:
1.
Licensees and applicants shall submit a report documenting the extending of test and maintenance procedures and Technical Specifications review to assure that post-maintenance operability testing of all safety-related equipment is required to be conducted and that the testing demoastrates that the equipment is 3
capable of performing its safety functions before being returned to service.
2.
Licensees and applicants shall submit the results of their check of vendor and engineering recomendations to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications, where required.
4.1 Reactor Trip System Reliability (Vendor-Related Modifications)
Position All vendor-recommended reactor trip breaker modifications shall be reviewed to verify that either:
(1) each modification has, in fact, been implemented; or (2) a written evaluation of the technical reasons for not implementing a modification exists.
For example, the modifications recommended by Westinghouse in NCD-I Elec-18 for the 08-50 breakers and a March 31, 1983, letter for the DS-416 breakers shall be implemented or a justification for not imple-menting shall be made available.
Modifications not previously made shall be incorporated or a written evaluation shall be provided.
4.5 Reactor Trip System Reliability (System Functional Testing) l Position 1
l On-line functional testing of the reactor trip system, ' including independent testing of the diverse trip features, shall be performed on all plants.
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The diverse trip features to be tested include the breaker under-voltage and shunt trip features on Westinghouse, Babcock and Wilcox (B&W) and Combustion Engineering (CE) plants; the circuitry used for power interruption with the silicon controllgd rectifiers on B&W plants; and the scram pilot valve and backup scram valves (including all initiating circuitry) on General Electric (GE) plants.
III. EVALUATION AND CONCLUSION By letter dat?d November 7,1983, TVA, the licensee of Sequoyah Nuclear Plant, Units 1 and 2, provided information regarding their compliance to Sections 3.1, 3.2, 4.1, and 4.5 of Generic Letter 83-28. We evaluated the licensee's responses against the NRC staff positions described in Section II above for completeness and adequacy.
We concluded that the licensee's responses to Action Items 3.1.1, 3.1.2, 4.1, and 4.5.1 were acceptable. The licensee's responses to Action Items 3.2.1 and 3.2.2 were determined to be incomplete and additional information is needed for us to complete our evaluation.
The information requested from the licensee is identified in the enclosure to the transmittal letter for this SE.
Dellr.eated below are the results of the required evaluations and a brief summary of the licensee's responses:
a.
Item 3.1.1-Review of Test and Maintenance Procedures and Technical Specifications (Reactor Trip System Components)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee confirmed in their response that Sequoyah's maintenance program does require post-maintenance testing and that the procedures for this testing require operability before the reactor trip system can be returned to service.
b.
Item 3.1.2 - Check of Vendor and Engineering Recommendations for l
Testing and Maintenance (Reactor Trip System Components)
The licensee's response to this item is acceptable and meets the intent of GL 83-28. The licensee indicated in the response that their Nuclear Experience Review Program ensures that vendor and engineering reconsnendations receive the appropriate distribution and review and verifies that test and maintenance procedures contain appropriate vendor and engineering recommendations.
The licensee stated that the Reactor Engineering Branch is responsible for ensuring that the industry experience information is distributed to the appropriate sections, by maintaining files with references, and responses for each item.
The licensee further stated that Nuclear Central office and plant staff within the area of their expertise will review this infor-mation and inform the responsible section as to its applicability.
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As part of their review for GL 83-28, the licensee stated that they requested Westinghouse Electric Corporation, the Nuclear Steam System Supplier at Sequoyah, to provide copies of those technical bulletins snd data letters which were not already in their files.
confimed that these bulletins and data letters have bees (he license or will be reviewed and evaluated for applicability to test and maintenance procedures.
Based on the above, we find this response to be accept-able.
c.
Item 3.2.1 - Review of Test and Maintenance Procedures and Technical Specifications (All Other Safety-Related Components)
The licensee's response to this item is incomplete and additional information is needed to determine acceptability.
It was concluded from review of the licensee's submittal dated November 7,1983, that the Nuclear Power Operational Quality Assurance Manual (0QAM) requires maintenance instructions to contain requirements for post-maintenance operational testing of critical structures, systems, and components (CSSC) prior to the equipment being returned to service.
It is also understood that the 0QAM requires maintenance requests to be reviewed by the responsible section and the Field Quality Engineering Section prior to the performance of maintenance on CSSC. However, it could not be determined from the licensee's response whether the post-maintenance test procedures were actually re-reviewed to detennine if the testing i
adequately demonstrates that the equipment is capable of performing its i
intended safety functions.
If the above review was performed, the licensee needs to submit an unambiguous statement confirming that post-maintenance test procedures were reviewed to ensure that the testing demonstrates that the equipment is capable of performing its safety functions.
d.
Item 3.2.2 - Check of Vendor and Engineering Recommendations for Testing and Maintenance (All Other Safety-Related Components)
'The licensee made the following statements in response to this item:
TVA's philosophy has always been to utilize engineering judgement, operating experience. TVA policy, and industry experience in conjunction with vendor and engineering recommendations to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications where
- required, i
This is supplemented by a program dealing with the review of operating experience reports.
This program establishes a system to ensure the review of operating experience reports.to document their applicability to TVA plants, to provide required written responses, and to ensure proper disposition of all applicable items.
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v Also, in order to comply with IE Bulletin 79-018 and NUREG-0588, class IE. electrical equipment is being reviewed for applicable maintenance instructions required to maintain the environmental qualification of the equipment.
This activity will be completed in accordar.cc with the NRC ruling on environmental q &lification.
In addition to the above, periodic review of procedures and instructions is required by the 0QAM to determine if changes are necessary or desirable.
This review is conducted no less frequently than every two years by an individual knowledgeable in the area affected by the procedure / instruction.
We have evaluated the above response and have concluded that it is incomplete and additional information is needed to detemine accept-ability. The licensee indicated that a two year review of procedures and instructions is required by the 0QAM to detemine if changes are necessary or desirable.- However, it is not quite clear from this response whether this r#tiew entailed a check of vendor and engineering recommendetions to ensure that appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications.
If the two year review does adequately verify that appropriate vendor and engineering recomendations have been incorporated into procedures, the licensee needs to provide a statement confirming that the require-ments of Action Item 3.2.2 have been completed.
If not, the licensee should submit a schedule for when this review will be completed.
e.
Item 4.1 - Reactor Trip System Reliability (Vendor - Related Modifica-tions)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee indicated that Westinghouse confirmed in a letter that the DB-50 breakers used at Sequoyah contain the modified (post-1972) undervoltage trip attachments.
The licensee stated that a t
l maintenance request has been issued for visual inspection of the DB-50 breakers to ensure that they have the post-1972 UVTAs.
The licensee comitted to have the inspections completed during subsequent refueling outages of Units 1 and 2.
In addition, the licensee has comitted to perform an inspection of power store's inventory to ensure that spare I
parts reflect the modifications. The licensee is requested to complete the above inspections in accordance with their commitments and provide the results to NRC in a final response.
i f.
Item 4.5.1 - Reactor Trip System Reliability (System Functional Testing)
The licensee's response to this item ist acceptable.
The licensee confirmed that current Technical Specifications and surveillance procedures require on-line functional testing of the automatic undervoltage trip function as part of the monthly logic i
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testing program for the reactor trip system. The Technical Specifica-tions require alternate trains of the reactor trip system be tested each month.
The licensee also stated that the automatic shunt trip bdification will include hard wired and component installation provisions for on-line surveillance testing that independently verifies the operability of the automatic undervoltage and shunt trip functions.
The licensee indicated that scheduling for this modification will be incorporated into the integrated schedule.
g.
Conclusion Based on our review, we conclude that the licensee's submittals to Action Items 3.1.1, 3.1.2, 4.1, and 4.5.1 are acceptable and meet the intent of GL 83-28. The licensee's responses to Action Items 3.2.1 and 3.2.2 are considered incomplete and additional information is needed to determine acceptability.
Acceptable responses to the above noted deficiencies are required before we can complete our review for the Sequoyah Plant Units 1 and 2.
We will review the response when received and will report our findings in a supplement to this safety evaluation.
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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION
'?
SEQUOYAH NUCLEAR PLANT l
GENERIC LETTER 83-28 ITEMS 3.2.1 AND 3.2.2 i l
- y A.
Item 3.2.1 - Review of Test and Maintenance Procedures and Technical Specifications (All Other Safety-Related Components)
It was concluded from review of you submittal dated November 7,1983, that the Nuclear Power Operational Quality Assurance Manual (0QAM) requires maintenance instructions to contain requirements for post-maintenance operational testing of critical structures systems and components (CSSC) prior to the equipment. being returned to service.
It is also understood that the 0QAM requires maintenance requests to be reviewed by the respon-sible section and Field Quality Engineering Section prior to the performance t
of maintenance on CSSC.
However, it could not be detemined from your response whether the post-maintenance test procedures were actually reviewed g~
s to determine if the testing adequately demonstrates that the equipment is capable of performing its intended safety functions.
If the above review was performed, you need to su' omit an unambiguous statement confirming.that s
post-maintenance test procedures were reviewed to ensure that the testing demonstrates that the equipment is capable of performing its intended safety functions.
s B.
Item 3.2.2 - Check of Vendor and Engineering Recomendations for Testing and Maintenance (All Other Safety-Related Components)
You indicated that a two year review of procedures and instructions is ss required by the 0QAM to deteimine if changes are necessary or desirable.
However, it is not quite clear from this response whether this review
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entailed a check of vendor and engineering recommendations to ensure that appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications.
If the two year review does adeouately g
verify that appropriate vendor and engineering recommendations hade' been l
incorporated into procedures, you need to provide a statement confirming s
that the requirements of Action Item 3.2.2 have been completed.
If.,not, you' should submit a schedule for when this review will be completed.
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