ML17156A245
| ML17156A245 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/03/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17156A244 | List: |
| References | |
| NUDOCS 8505160357 | |
| Download: ML17156A245 (11) | |
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0 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION AMENDMENT NO.
TO NPF-14 SUS UEH NNA S E
ELEC RIC STATION, UNIT 1 DOCKET NO. 50-387 Introduction By letter dated April 9, 1985, from B. Kenyon of Pennsylvania Power 5 Light Company (PP&L) to A. Schwencer, NRC, the licensee requested Technical Specification changes for Susquehanna Steam Electric Station Unit 1 (SSES-1).
These changes are. related to the required use and operability of the Source Range Monitors (SRM) during reloading (or unloading) of the entire core.
The requested Technical Specification changes for SSES-1 actually take the form of removing the SRM minimum count rate operability requirement when there are eight or fewer fuel assemblies in the reactor.
Evaluation During reload operations the Technical Specifications require minimum count rate levels to be met in order to meet the operability requirement for the SRMs.
In the case of SSES this is 0.7 counts/second with a signal to noise ratio of at'east 2.
During reload operations in a BMR in which the entire core is unloaded, there may be times, when too few fuel assemblies are in the core, to meet the minimum count rate necessary to get a reading from the SRMs.
For this condition other monitors, Fuel Loading Chambers (FLC); usually called "dunking chambers",
which can be moved from place to place in the core as loading proceeds, are used as a replacement for the SRM's.
Some utilities have found that the FLC's are an impediment to operations.
The licensee has stated that during the SSES Unit 1 end-of-cycle defueling the FLCs, which were being used to provide neutron monitoring, produced anomalous readings which were attributed to detector satura-tion caused by the high gamma flux existing from the irradiated fuel.
During the past several years several other utilities have requested Technical Specification changes to permit loading operations such that the use of FLCs can be avoided.
An example being the most recently approved Technical Specification revision for Browns Ferry.
The loading operation for full core reloads involving.irradiated fuel may begin without minimum count rates for the SRM for a limited number of assembly"loadings (determined to be subcritical).
-'hese loadings place irradiated fuel adjacent to SRM locations.
This provides sufficient neutron sources (e.g.
from gamma-neutron reactions) to meet the Technical Specification minimum SRM count rate requirements.
After the SRMs are thus fully operational the loading proceeds in the usual manner, (e.g.,
- spiral loading=from the. center-for-Browns-Ferry)..
PPIlL pr'oposes (for full core'reloads with irradiated fuel as part-oF-the-- ---
reload) to begin the reload by first inserting 8 irradiated assemblies (into a fully controlled core).
There will be 2 assemblies adjacent to each of the four SRMs.
The SRMs are in a square array 6 control cells apart.
This proposed method is expected to provide the required SRM count rate of 0.7 counts/
second with a 2 to 1 source/noise ratio. If the count rate is not reached the FLC's will be used as a backup.
8505160357 850503T,'i PDR ADOCK 05000387 P
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The licensee determined that the 8 assemblies in a maximized state with a clustered, uncontrolled configuration would be subcritical and that there would be no possibility of reaching criticality during the loading around the SRNs.
Based on calculations previously seen by the staff these subcriticality results are acceptable.
The actual conditions are controlled (all rods in).
The 4 separate regions of 2 assemblies do not interact making actual conditions far more subcritical than the calculated results show.
Loading patterns to be used following the first 8 assemblies are selected to maintain a continuous multiplying medium between the operating SRM and the loading region to enhance the response of the SRH to the loading changes.
During unloading the last fuel to be removed will be adjacent to the SRHs.
Except for the SRH count rate during the first (last) 8 assembly loading (unloading), all normal limits and control interlocks'will be in effect at all times.
The licensee has requested Technical Specification changes to implement this procedure.
The changes affect Table 3.3.6-1 (Control Rod Block Instrumentation) in a footnote to the SRN down-scale trip operable channels requirements, and also the Specification 3.9.2 (Refueling Operation-Instrumentation) for SRH requirements.
In both cases the change indicates that the SRHs are not required (i.e., the minimum count rate for operability is not required) when 8 or fewer fuel assemblies (which would be adjacent to SRM) are in the core.
The bases for 3.9.2 is augmented to indicate the loading scheme.
The essence of the loading. scheme, to provide a subcritical configuration while providing for a suitable count rate for the SRM and the subsequent well monitored loading for the remainder of the core, is 'the same as that proposed and approved for Browns Ferry.
The loading pattern to be used following SRN operability, which is directly interconnected to the SRN, is somewhat different than the Browns Ferry central spiral loading pattern.
Our review has indicated that PP8L's proposal is more directly related to the SRH count rate and is fully acceptabl,e.
Conclusions PP&L has requested Technical Specification changes for Susquehanna Unit I which would remove during the loading (unloading) of the first (last) 8 fuel assemblies (adjacent to the SRM) the requirement that the SRN meet the minimum count rate requirement with fuel in the core.
Other. loading require-ments will be unchanged.
The primary reason for wanting the change is to eliminate the need for FLCs ("dunking chambers")
during loading operations.
The primary basis for the safety of the requested change is that the core will be well below criticality during the loading of the 8 assemblies, and subsequent loading will be well monitored by the SRMs.
Our review has concluded that the process is acceptable and that the requested Technical Specification changes appropriately implement this process.
The NRC staff approves this change.
Final No Siqnificant Hazards Consideration (SHC) Determination The Commission made a proposed determination that this amendment involves no significant hazards consideration (SHC).
Notice of Consideration of Issuance of Amendment to Facility Operating License and Proposed No Significant Hazard Consideration Determination was published in the Federal Register on April 19, 1985 (50 FR 15664).
This amendment is being issued before expiration of the 15-day comment period because failure to do so would result in the licensee's inability to reload the core, delaying day for day the restart of Unit 1.
The State of Pennsylvania was consulted and did not have any comments.
Based on the Commission's final review, the Commission has made a final determination that this amendment involves no significant hazards consideration.
Because th'e core will be subcritical during the loading of the initi'al 8 assemblies and subsequent loading will be well monitored by the SRMs, the proposed amendment does not involve a significant increase in the probability or consequences of
'an accident previously evaluated or a significant reduction in the margin of safety, or create the possibility of a new or different kind of accident from an accident previously evaluated.
Environmental Consideration This amendment involves a change in the installation or use of a facility component located within the restricted area defined in 10 CFR Part 20.
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 the individual or cumulative occupational radiation exposure.
The Commission has made a final no significant hazards consideration finding with respect to this amendment.
Accordingly, this 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 this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) the amendment (a) does not significantly increase the probability or.
consequences of accidents previously considered, (b) does not create the possibility of a new or different kind of accident from any accident previously evaluated and (c) does not significantly reduce the margin of safety, and the amendment, therefore, does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated:
May 3, 1985
Docket No. 50-387 May 3, 1985 Mr. Norman W. Curtis Vice President Engineering and Construction Nuclear Pennsylvania Power 5 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101
Dear Mr. Curtis:
J
SUBJECT:
AMENDMENT NO.
43 TO FACILITY OPERATING LICENSE NO. NPF-14 SUSQUEHANNA STEAM ELECTRIC STATION, UNIT 1 The Nuclear Regulatory Commission has issued the enclosed Amendment No. 43 to Facility Operating'License No.
NPF-14 for the Susquehanna Steam Electric Station, Unit 1.
The amendment is in response to your letter dated April 9, 1985 as supplemented
'on April 25, 1985.
This amendment revises the Technical Specifications -relating to SRM operability during reloading or off-loading of the entire core'when the core contains', irradiated fuel.
J This amendment was authorized by telephone on April o, 1985 and confirmed by letter on April So, 1985.
A copy of the related safety evaluation 'supporting Amendment No. 43 to Facility Operating License NPF-14 is enclosed.
Sincerely, J
J A. Schwencer, Chief Licensing Branch No.
2 Division of Licensing
Enclosures:
1.
Amendment No.43 to NPF-14 2.
Safety Evaluation cc w/enclosure:
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Docket No. 50-387 Mr. Norman W. Curtis Vice President Engineering and Construction Nuclear Pennsylvania Power 8 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101
Dear Mr. Curtis:
SUBJECT:
AMENDMENT NO.
TO FACILITY OPERATING LICENSE 0.
NPF-14 SUSQUEHANNA STEAM ELECTRIC STATION, UNIT 1 The Nuclear Regulatory Commission has issued the closed Amendment No.
to Facility Operating License No.
NPF-14 for th Susquehanna Steam Electric Station, Unit 1.
The amendment is in respons to your letter dated April 9, 1985.
This amendment revises the T chnical Specificatios relating to SRM operability during reloading or off ading of the entire core with irradiated fuel.
A copy of the related safety evaluatio supporting Amendment No.
to Facility Operating License NPF-14 is dnclosed.
Sincerely,
Enclosures:
1.
Amendment No.
to F-14 2.
Safety Evaluation cc w/enclosure:
See next page Distribution:
See next page A. Schwencer, Chief Licensing Branch No.
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FOR THE NUCLEAR REGULATORY COf1MISSION
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