ML20248B487
| ML20248B487 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/05/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20248B454 | List: |
| References | |
| NUDOCS 8906090072 | |
| Download: ML20248B487 (6) | |
Text
. _ - - - - -. _ - _ -
+#
og UNITED STATES
- [
g NUCLEAR REGULATORY COMMISSION i
7.
j WASHINGTcN, D, C. 20665 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
98 TO FACILITY OPERATING LICENSE NO. OPR-70 PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY SALEM GENERATING STATION, UNIT NO. I DOCKET NO. 50-272
1.0 INTRODUCTION
By letter dated May 5, 1989, Public Service Electric & Gas Company requested an amendment to Facility Operating License Nos. DPR-70 and DPR-75 for the Salem Generating Station, Unit Nos. I and 2.
The proposed amendments would delete the requirement in the Salem Technical Specification that the measured drag force of a mechanical snubber should nt,t increase by inore than 50% from the previous test result. The licensee contends that the current drag force comparison requirement which was inteeded tc trend increases in drag force in order to predict impending snubber failure is not valid for Pacific Scientific Mechanical Snubbers.
This requirement may cause an unnecessary increase in the. snubber test population even if the drag force is well below the acceptance criteria and may also result in a substantial increase in worker radiation exposure.
2.0 EVALUATION This proposed change would revise Section 4.7.9.e.1 of the Salem Unit 1 Technical Specifications. The change would delete an aspect of mechanical snubber surveillance test acceptance criteria which requires a verification that the snubber drag force has not increased more than 50% since the previous functional test.
As described in LER 272/89-015-00 dated April 19, 1989, Salem Generating Station has not, in the past, performed the subject drag force comparison.
However, since drag forces were measured and documented, it was possible to review the functional test data and apply the 50% criterion. This review indicated that (prior to the current Salem Unit 1 outage) four snubbers at Salem Unit I and nine snubbers at Salem Unit 2 had failed to meet the criterion. Only one of these snubbers, in Unit 2, was still in use and was replaced in April, 1989. None of these nine snubbers tested have exhibited drag forces more than 50% higher than those previously measured.
1 8906090072 890605 PDR ADOCK 05000272 P
. f The snubber manufacturer (Pacific Scientific) has generated data related.
to mechanical snubber drag force loading. The results of these tests indicate that an increase in drag force from one inspection period to.the next does not establish a trend that can be used to predict pending snubber failure. Based on this data, PSE&G concludes that a 50% increase in measured drag force from one inspection. period to the next is no cause for. declaring the snubber inoperable if the load is below the maximum allowable value.
The~ intent of the current drag force comparison requirement is to trend ~
increases' in drag force in ordar to pedict impending snubber failure.
However, the aforementioned Pacific Scientific test report indicates that an increas:: in drag force is not a valid indicator.of:isuninent snubber failure. This supports the position that a 50% increase in drag force is-not sufficient cause for declaring a snubber inoperable.
The Sales test results provided by the licensee support the position that the drag f(,rce comparison is not an adequate predicator of snubber
~ failure. The data indicates that as many snubber drag forces have decreased as have increased from previous measurements without any identifiable correlation to snubber failures. These variations appear to be within the expected statistical variation considering the techniques and equipment'used.
NRC has approved the deletion of the 50% drag force change comparison requirement from the Westinghouse Standard Technical Specifications in addition tc approving license changes identical to this one for other.
plants. This requirement has not been included in the snubber technical specifications for more recent operating licenses (such as Hope Creek).
The proposed change does not affect other aspects of snubber surveillance program and the primary acceptance criteria. Verification is required that the drag force is less than the specified allowable value.
Compliance with ASME Section XI per Technica1' Specification 4.0.5 remairs unchanged.
Based on a review of the data provided by the licensee, Staff concludes that the proposed amendment for the deletion of the Salem Generating Station Unit I requirement in Technical Specification 4.7.9.e.1 that the measured drag force of a mechanical snubber should not increase by more than 50% from the previous test result, is acceptable.
3.0 EMERGENCY CIRCUMSTANCES During the current Salem Unit 1 outage, surveillance testing has identified a number of mechanical snubbers in the area of the pressurizer that have experienced an increase in drag force of more than 50 percent from the previous measurement. Due to the number of snubbers exceeding this drag force comparison criterion (6 out of 21 tested), an expanded 4
sample of mechanical snubbers must be selected for functional testing due
=
I
[F i' to Technical Specification 4.7.9.e.1 requirement. Eipanding the test sample for this reason could very possibly lead to the testing of the-entire mechanical snubber population (81 snubbers). This amount of.
testing would require an additional 1000 man-hours of work and would result in an estimated increase in radiation exposure of approximately 40 man-rem, primarily due to the number of mechanical snubbers located ~in the vicinity of the pressurizer (48). This radiation exposure level could increase depending on the results of the additional testing and any required repair or replacement activity. The increased inspections could not have been reasonably foreseen since there has been no evidence of a trend toward increased drag force. The test results to date do not show a trend toward increasing drag force.
Without the proposed change, a significant addition to the outage man-rem exposure would result without any increase in safety.
Salem Unit 1 is scheduled to be synchronized with the grid on May 24, 1989.
Without this relief the restart of Salem Unit I would be delayed.
It is therefore concluded that this change satisfies the criteria of 10CFR 50.91(a)(5).
This amendment was authorized by telephone on May 12, 1989 and confirmed by letter dated May 12, 1989.
4.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commission's regulations in 10 CFR 50.92 state the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the amendment would not:
(1)
Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated or; (3) Involve a significant reduction in a margin of safety.
The staff has determined the following:
A.
Operation of the facility in accordance with the proposed amendment would not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed change does not change the following aspects of the snubber surveillance program:
E..
p-s 1).
Visual inspections and associated acceptan"ce criteria, which
~
o include manual verification of freedom of movement where i
possible.
2)
Retesting of any snubbers and/or replacements which failed the L
previous test.
3)
Testing of all-snubbers of the same design as a snubber selected for functional testing and fails to move or fails to lockup due to a design or manufacturing defect.
4)
Verification that the drag force is less than the specified y
allowable value.
5)
Verification that activation is achieved within the range of velocity or acceleration specified for both tension and compression.
6)
Verification of acceptance release rate or ability to withstand load without displacement, as applicable.
7)
Compliance with ASME Section XI per Technical Specification 4.0.5.
The measures listed eboye comprise an adequate program for assuring snubber operability. Verif specified allowable limit (ying that drag force is within itsItem 4 above) is th determining that the drag force is acceptable. The relevant specified parameters for each snubber subjected to functional testing will still be verified to be within allowable limits. Consequently, the proposed change does not increase the likelihood of snubber inoperability, nor does it increase the adverse effects of such inoperability on the associated systems.
)
The snubbers are included in the system design to mitigate the effects of a seismic event and allow for thermal expansion of the piping. The functional testing described above will determine the capability of the snubber to meet these requirements. The 50% drag force load comparison currently recuired by Technical Specification 4.7.9.e.1 does not supplement the operability determination of the j
snubber and can be deleted without adverse impact on the associated I
system.
Therefore, it may be concluded that the proposed change does not L
involve a significant increase in the probability or consequences of F
an accident previously evaluated.
B.
Operation of the facility in accordance with the proposed amendment would not create the possibility of a new or different kind of accident from any previously evaluated.
1
c I l The proposed change does not involve changes to'the design or application of snubbers.
It does not involve any design or i
configuration changes to the plant. No new accident scenarios or new component failure mechanisms are introduced. Therefore, it may be concluded that the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.
C.
Operation of the facility in accordance with the proposed amendment would not involve a significant reduction in a margin of safety.
Snubbers provide assurance that the strcctural integrity of the fluid systems subjected to dynamic loads is maintained. The margin of safety associated with snubbers is related to the specified allowable limits imposed on performance parameters, including maximum allowable drag force. This change proposes to delete a test acceptance criterion related to a change in the measured drag force, and does not increase the maximum allowable value. Therefore, it may be concluded that the proposed change does not involve a reduction in a margin of safety as defined by the Technical Specifications. Based on the above discussion the staff concludes that this amendment meets the criteria and therefore does not involve a significant hazards consideration.
5.0 STATE CONCLUSION The State of New Jersey was consulted on this matter and had no comments on the determination.
6.0 ENVIRONMENTAL CONSIDERATION
The amendment involves a change to a requirement with respect to the inst &llation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has made a final no significant hazards finding with respect to this amendment. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
I
7.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) the amendment deet not (a) significantly increase the probability or consequences of an accident previously evaluated, (b) increase the possibility of a new or different kind of accident from any
l previously evaluated or (c) significantly reduce a safety margin and, therefore,-the amendment does not involve significant hazards consideration; (2) there is reasonable assurance that the health and safety of the-will not be endangered by operation in the proposed manner, and (3) public such activities will be conducted in compliance with the Commission's regulations and the issuance of the amendrent will not be inimical to the common defense and security nor to the health and safety of the public.
Principal Contributors:
J. Rajan and J. Stone l
Dated:
June 5, 1989 I
_