ML18030B257
| ML18030B257 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/14/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18030B255 | List: |
| References | |
| GL-83-28, TAC-52901, TAC-52902, TAC-52903, TAC-53737, TAC-53738, TAC-53739, TAC-53964, TAC-53965, TAC-53966, NUDOCS 8604210434 | |
| Download: ML18030B257 (13) | |
Text
~p,ll REgy 0~c
+a*++
t UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SALEM ANTICIPATED TRANSIENT WITHOUT SCRAM (ATWS G
N RIC LE TER 83-TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2 AND 3 DOCKET NOS. 50-259, 50-260 AND 50-296 INTRODUCTION By letter dated November 7, 1983 as supplemented March 15, 1984, the Tennessee Valley Authority (TVA or the licensee) responded to Generic
'etter (GL) 83-28 for the Browns Ferry Nuclear Plant, Units 1, 2 and 3
(BFNP).
GL 83-28 concerned actions required by the NRC based on the generic implications of the Salem ATWS events.
BACKGROUND 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 GL 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,
'lassification of equipment, vendor interface, post-maintenance
- testing, and RTS reliability improvements.
REVIEW GUIDELINES The licensee's responses were evaluated for compliance to the staff positions delineated in GL 83-28 for Action Items 3. 1. 1, 3. 1.2, 3.2. 1, 3.2.2 and 4.5. 1.
Item 4. 1 is not applicable to Browns Ferry Units 1, 2
and 3, therefore; a response was not required.
The requirements of the above action items, as described in the GL, are paraphrased below:
Bg0+2f0434 B60+0~++~9 pDR ADQCK 0 pDR P
- 3. 1 Post-Maintenance Testing (Reactor Trip System Components)
Position 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 Spec~7ications to assure that post-maintenance operability testing of safety-related components in the reactor trip system is required to be conducted 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 of their check of 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.
3.2 Post-Maintenance Testing (All other Safety-Related Components)
Position The following actions are applicable to post-maintenance testing:
2.
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 demonstrates that the equipment is capable of performing its safety functions before being returned to service.
Licensees and applicants shall submit the results of their-check of 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.
4.1 Reactor Trip System Rel iabi1 ity (Vendor-Rel ated 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 modifications exists.
For example, the modifications recommended by Westinghouse in NCD-Elec-18 for the DB-50 breakers and a March 31, 1983, letter for the DS-416 breakers shall be implemented or a justification for not implementing 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) position On-line functional testing of the reactor trip system, including independent testing of the diverse trip features, shall be performed on all plants.
1.
The diverse trip features to be tested include the breaker undervoltage and shunt trip features on Westinghouse, Babcock and Wilcox (BSW) and Combustion Engineering (CE) plants; the circuitry used for power interruption with the silicon controlled rectifiers on BSW plants; and the scram pilot valve and backup scram valves (including all initiating circuitry) on General Electric (GE) plants.
IV.
EVALUATION AND CONCLUSION By letters dated November 7, 1983 and March 15,
- 1984, TVA, the licensee of Browns Ferry Nuclear Plant, Units 1, 2 and 3, provided information regarding their compliance to Sections
- 3. 1. 1, 3. 1.2, 3.2. 1, 3.2.2, and 4.5. 1 of GL 83-28.
We evaluated the licensee's responses against the NRC staff's positions described in Section II above for completeness and adequacy.
We concluded that the licensee's response to Action Item 4.5.1 was acceptable.
The licensee's responses to Action Items 3. 1.1, 3. 1.2, 3.2. 1 and 3.2.2 were determined to be incomplete; therefore, the acceptability of these items cannot be determined without the additional information from the licensee, which is identified in Enclosure 2 to the transmittal letter for this SE.
Delineated 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 Tech'nical Specifications (Reactor Trip System Components)
The licensee's response to this item is incomplete and additional information is needed to determine acceptability.
It is clear from the response that the licensee has established administrative procedures to assure that post-maintenance testing is performed on critical systems, structures, or component equipment.
In the
- response, the licensee made the following statements:
"Technical Specifications for Browns Ferry list the limiting conditions and surveillance requirements for unit operability for the reactor protection system.
Browns Ferry's Standard Practices require that post-maintenance testing be performed.
Standard Practice BF13. 1, "Format for Maintenance Instructions," establishes the format for maintenance instructions and provides for post-maintenance testing of affected components to establish operability.
Standard Practice BF6. 1, addresses the required post-maintenance testing of affected components to establish operability.
BF6. 1 is the governing document for performing maintenance and is supported by the document listed in the referenced section.
Standard Practice BF7.5, "Maintenance Request and Tracking," establishes the instructions and responsibility for identifying, requesting, and authorizing maintenance.
BF7.5 requires that all plant personnel report the need for corrective maintenance on plant equipment or systems by the use of Maintenance Request (MR) form TVA 6436.
Identification of the problem, corrective measures to be taken, and any post-maintenance testing required shall be documented on the MR.
BF7.6 identifies those responsible for completing the section of the MR addressing post-maintenance testing and how to address this item.
BF7.6 requires that any pre/post-maintenance testing or quality control (gC) hold-points required be identified on the MR form.
MRs for Critical Structures Systems and Components (CSSC) safety-related equipment are reviewed and approved by the quality engineering (gE) before performance of work. unless the work is scheduled preventative maintenance using previously approved instructions.
Following completion of the work, the responsible maintenance'ection representative shall review the MR to determine that the work was acceptable.
This representative shall verify that all post-maintenance test requirements were met.
The MR is then reviewed by the field gE section to determine completeness as quality assurance (gA) records."
It cannot be concluded from reviewing the above statements whether the licensee has actually re-reviewed those maintenance procedures to assure that the post-maintenance testing adequately demonstrate that the equipment is capable of performing its intended safety functions prior to being returned to service.
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 adequately verifies component capability to perform its intended safety functions.
b.
Item 3. 1.2 - Check of Vendor and Engineering Recommendations for Testing and Maintenance (Reactor Trip System Components)
The licensee's response to this item is incomplete and additional information is needed to determine acceptability.
The licensee indicated that they have a program in place for the review of operating experience reports (OERs) which include vendor and engineering recommendations.
The program establishes a system to ensure the review, evaluation, and disposition of all applicable items.
The licensee stated that the Reactor Engineering Branch is responsible for coordinating this review, disseminating the information to the appropriate organizations that could be affected by this experience and ensuring that the recommendations made by the reviewing organizations are addressed by the plant.
The licensee stated that a review of General Electric Company's Service Instruction Letters (SILs) has been conducted and it had been determined that the plant has been sent all applicable SILs with recommended
- action, when required.
The licensee also identified those procedures used at the site for reviewing plant instructions and Operating Experience Reports.
It appears from this response that all appropriate vendor test guidance, such as GE SILs for reactor trip system components have been properly incorporated into test procedures.
However, the licensee did not specifically state this in their response.
Therefore, to confirm our conclusion, the licensee should provide an unambiguous statement confirming that site procedures BF2.14 (2-year review) and BF21.17 ensure that appropriate test guidance has been included in the test and maintenance procedures or the Technical Specifications, where required.
C.
f 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 guality Assurance Manual (0(AM) 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 0(AM requires MRs to be reviewed by the responsible section and the Field guality 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 reviewed to determine if the testing adequately demonstrates that the equipment is capable of performing its 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 adequately verified component capability to perform its intended 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:
"TYA'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.
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'll applicable items.
Also, in order to comply with IE Bulletin 79-01B and NUREG-0588, class 1E electrical equipment is being reviewed for
'pplicable maintenance instructions required to maintain the environmental qualification of the equipment.
This activity will be completed in accordance with the NRC ruling on environmental qualification.
In addition to the above, periodic review of procedures and instructions is required by the 0(AM 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 determine acceptability.
The licensee indicated that a two year review of procedures and instructions is required by the 0(AM to determine if changes are necessary or desirable.
However, it is not quite clear from this response whether this review 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 adequately verify that appropriate vendor and engineering recommendations have been incorporated into procedures, the licensee needs to provide a statement confirming that the requirements of Action Item 3.2.2 have been completed.
If not, the licensee should submit a schedule for when this review will be completed.
Item 4.1 - Reactor Trip System Reliability (Vendor - Related Modifications)
This item is applicable only to Pressurized Water Reactors, therefore, no response is required by Browns Ferry since it is a
Boiling Water Reactor.
Item 4.5. 1 - Reactor Trip System Reliability (System Functional Testing)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee confirmed in its response dated March 15, 1984, that the Reactor Protection System (RPS) with its associated relay logic, multiple and diverse sensor
- channels, and actuation devices are tested on-line and that this testing is consistent with achieving a high sensor system reliability.
The licensee stated that each RPS sensor channel functional test includes full actuation of the associated logic, the two output scram contactors in each channel, and the scram solenoid valves are electrically cycled during these tests, operability of each pair of these valves can only be verified by actual insertion of the appropriate control rods and that BF Technical Specifications provide requirements on the frequency of testing the control rods.
In addition to the primary RPS scram logic, a backup scram function is accomplished by two solenoid valves which isolate the main air supply and vents the air supply header which connects to the individual hydraulic control units.
The licensee indicated that half of the backup scram logic is actuated for each valve during channel functional tests; however, on-line actuation of the backup scram valves cannot be accomplished without a complete scram signal present.
The licensee further stated that the indicator lights located in the main control room are wired in such a way that the indicator lights can verify operation of the appropriate RPS channel scram contactor during routine RPS channel surveillance testing and can also verify continuity through the backup scram valve solenoid coils during plant operation.
Based on our review of the above, we find the licensee's response to be acceptable.
Conclusion e
Based on our review and inspection, we conclude that the licensee's submittals to Item 4.5. 1 are acceptable and meet the intent of GL 83-28.
The licensee's responses to Action Items 3.1.1,
- 3. 1.2, 3.2. 1, and 3.2.2 are considered incomplete, thus requiring additional information to determine acceptability.
Acceptable responses to the above noted deficiencies are required before we can complete our review for the Browns Ferry Plant, Units 1, 2, and 3.
We will review the response when received and will report our findings in a supplement to this Safety Evaluation.
Principal Contributor:
T. E. Conlon Dated:
April 14, 1986
RE/VEST FOR ADDITIONAL INFORMATION BROWNS FERRY NUCLEAR PLANT GENERIC LETTER 83-28, ITEMS 3. 1. 1, 3. 1.2, 3.2. 1, AND 3.2.2 A.
Item 3. 1. 1 - Review of Test and Maintenance Procedures and Technical Specifications (Reactor Trip System Components)
It was concluded from review of the submittal dated November 7, 1983, that the Nuclear Power Operational guality Assurance Manual (0(AM) requires that maintenance instructions 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 0(AM requires MRs to be reviewed by the responsible section and Field guality Engineering Section prior to the performance of maintenance on CSSC.
However, it could not be determined from the response whether the post-maintenance test procedures were actually re-reviewed to determine if the testing adequately demonstrates that the equipment is capable of performing its intended safety functions.
If the above re-review was performed, TVA must submit a
unambiguous statement confirming that post-maintenance test procedures were reviewed to ensure that the testing adequately verifies component capability to perform all safety functions.
B.
Item 3. 1.2 - Check of Vendor and Engineering Recommendations for Testing and Maintenance (Reactor Trip System Components)
TVA indicated that a two year review of procedures and instructions is
,required by the 0(AM to determine if changes are necessary or desirable.
However, it is not quite clear from this response whether this review entailed a check of vendor and engineering recommendations to ensure that appropriate test guidance is included i the test and maintenance procedures or the Technical Specifications.
If the two year review does adequately verify that appropriate vendor and engineering recommendations have been incorporated into test and maintenance procedures, TVA must provide a statement confirming that the requirements of Action Item 3. 1.2 have been completed.
If not, TVA should submit a schedule for when this review will be completed.
C.
Item 3.2. 1 - Review of Test and Maintenance Procedures and Technical Specifications (All Other Safety-Related Components)
It was concluded from review of the submittal dated November 7, 1983, that the Nuclear Power 0(AM requires that maintenance instructions 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 0(AM requires maintenance request to be reviewed by the responsible section and Field guality Engineering Section prior to the performance of maintenance on CSSC.
However, it could not be determined from the response whether the
post-maintenance test procedures were actually re-reviewed to determine if the testing adequately demonstrated that the equipment is capable of performing its intended safety functions.
If.the above re-review was performed, TVA must submit an unambiguous statement confirming that post-maintenance test procedures were reviewed to ensure that the testing adequately verifies component capability to perform all safety functions.
Item 3.2.2 - Check of Vendo'r and Engineering Recommendations for Testing and Maintenance (All Other ~Safety-Related Components) i TYA indicated that a two year review of procedures and instructions is required by the 0(AM to determine if changes are necessary or desirable.
However, it is not clear form this response whether this review entailed a check of vendor and engineering recommendations to ensure that appropriate test guidance i's included in the test and maintenance procedures or the Technical'. Specifications.
If the two year review does adequately verify that appropriate vendor and engineering recommendations have been incorporated into test and maintenance procedures, TYA must provide a statement confirming that.the requirements of Action Item 3.2.2 have been completed.
If not, TVA should submit a schedule for when this review will be completed.
t