ML20136J035
| ML20136J035 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/19/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20136H931 | List: |
| References | |
| NUDOCS 8511250265 | |
| Download: ML20136J035 (9) | |
Text
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o UNITED STATES g
8 NUCLEAR REGULATORY COMMISSION o
3 5
WASHINGTON, D. C. 20655
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 91 TO PROVISIONAL OPERATING LICENSE NO. DPR-16 GPU NUCLEAR CORPORATION AND JERSEY CENTRAL POWER & LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219
1.0 INTRODUCTION
By letter dated October 11, 1985, as revised by its letter dated October 18, 1985, and supplemented by its letter dated October 22, 1985, GPU Nuclear (the No. DPR-16 for the Oyster Creek Nuclear Generating Station (OCNGS)g License licensee) requested an emergency amendment to Provisional Operatin This amendment would authorize a change to Item J.4 of Table 3.1.1, Protective Instrumentation Requirements, for Section 3.1, Protective Instrui.entation, of the Appendix A Technical Specification (TSs). The proposed change qualifies when the low-low reactor water level instrumentation has to be operable in the shutdown reactor mode condition for Reactor Building isolation.
Specifically, the change would allow this instrumentation to be inoperable in shutdown and, under certain conditions, the Reactor Building is not required to be isolated and the Standby Gas Treatment System (SGTS) is not required to be operating.
As the licensee has requested, this would be a one-time-only change effective only for the Cycle 10M outage which began October 18, 1985.
A Notice of Issuance of. Amendment to License and Final No Significant Hazards Consideration Determination and Opportunity for Hearing related to the requested action will be published in the C mmission's biweekly publication notice in the Federal Register.
In its application of October 11, 1985, the licensee proposed another change.
This change was to Item B.1 of Table 3.1.1 to qualify when the low-low reactor water level instrumentation had to be operable in shutdown for reactor isolation.
This proposed change is not part of this amendment and will be the subject of a separate licensing action. This requested action would not cause derating)or shutdown of this facility and, therefore, doesnot under The action required by the TSs for reactor isolation when this instrumentation is inoperable can be taken without affecting the restart of Oyster Creek.
2.0 DISCUSSION The licensee is planning a special maintenance outage for the plant in order to complete, among other items, equipment changes required to comply with the Environmental Qualification rule (10 CFR 50.49) which requires compliance by November 30, 1985. Among these changes is the replacement of several reactor water level instrument transmitters.
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' The water level instrumentation system at Oyster Creek consists of five types of level channels, each of which includes redundant channels as shown in the following figure.
The first type is the " fuel zone" set of monitors which cover the range of l
+180 inches to -144 inches (where "zero" for all channels is the top of the active fuel). This type channel provides indication in the control room but does not provide any automatic actions. The second type is the RE-18 set of Barton instruments which cover the range of +185 inches to +55 inches (above the top of the active fuel). This type has no indication in the control room but provides automatic safety actions at the " low-low-low" setpoint (+55 inches). The third type includes the RE-02 set of Yarway instruments which cover the range of +185 inches to +86 inches (above the top of the active fuel).
This type has lusl indication and provides automatic safety actions at the
" low-low" setpoint (+86 inches). This type also includes the RE-05/19 set of Yarway instruments which covers the same range, has control room and local indication, and provides automatic safety actions at the "hi" level setpoint
(+176 inches) and at the " low" level setpoint (+138 inches). The fourth type is the 10-13 narrow range GE/MAC instruments which are " hot calibrated" to cover the range of +185 inches to +90 inches (above the top of the active fuel).
This type has control room indication, has automatic control function, and is used primarily during normal power operation. This type also includes an alann at a high level value of +176 inches and at a low level value of +147 inches, where the nominal operating level is +165 inches. The fifth type is the ID-12 wide range GE/MAC instruments which are " cold calibrated" to cover the range of +490 inches to +90 inches (above the top of the active fuel).
The licensee's planned equipment changes are to be conducted with the plant in cold shutdown and include replacing the transmitters and rerouting of the hydraulic sensing lines within the instrument racks for all the channels in the first and third types presented above. The issues of safety concern include the adequacy of the control room indication of the remaining channels and the automatic safety actions that would have been provided by the channels that will be out of service during the replacements.
3.0 EVALUATION The nature of the modifications is such that the root valves for each set of sensing lines will have to be closed.
In our review, the staff raised questions regarding the feasibility (of isolating only one side of the reactor vessel level instruments at a time i.e., channels A and B, and then channels C and D). This approach would have the benefit of leaving one side operable and capable of providing indication and automatic safety action throughout the modification process. The licensee stated that to replace all of the sets of instruments simultaneously has been estimated to require 24 days and that to replace only one side at a time would require an additional outage time of at least 20 days. The licensee has stated further that this aspect of the outage is the critical path item and that the work time estimates have been carefully scrutinized and are believed to be realistic. Accordingly, if the TS change is approved, the licensee plans to replace all the affected instruments simultaneously on a two, 10-hour shift basis.
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GPU NUCLEAR CORPORATION REACTOR WATER LEVEL INSTRUMENTATION OYSTER CREEK NUCLEAR GENERATING STATION UPDATED FINAL SAFETY ANALYSIS REPORT REV. O.12/84 l
FIGURE 7.6 3
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The staff requested the NRC Resident Inspectors review the licensee's work I
orders for this modification. The NRC Resident Inspectors stated that they believed the licensee's work time estimates were reasonable.
The affected reactor vessel level instrumentation includes these channels that provide automatic safety action at hi-level, low-level, and low-low-level.
These actuation and/or control functions are in FSAR Table 7.6-1.
These include initiation of core spray, containment spray, containment isolation, and the SGTS. The licensee has reviewed each of these actions and has detemined that the T5 allow each to be disabled when the plant is in cold shutdown, with the exception of SGTS initiation and Reactor Building isolation.
We agree with this detemination. The licensee requested a TS change to not require, under certain conditions, automatic actuation of SGTS and Reactor t
Building isolation upon "lo-lo" water level.
I The change would add footnote "gg" to item J.4. of Table 3.1.1.
This footnote l
would require that during shutdown the water level be monitored by the operator l
l and SGTS be initiated manually if any of the remaining operable level l
instruments indicate a level corresponding to the " low" level setpoint or less.
During these modifications, the plant will either be maintained such that i
l secondary containment is not required, as defined in TS 3.5.8.1, or the i
conditions of T$s 3.5.b.1.a,b,c and d are met.
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The staff raised the question of whether the SGTS could re-establish an l
adequate negative pressure in the Reactor Building if the normal ventilation i
system were to become disabled.
The Ifcensee agreed to manually initiate SGTS in the event the nomal Reactor Building ventilation system is lost and cannot be restarted imediately.
The Ifcensee stated that this action will be i
implemented by a special written directive to the reactor operators. This l
directive was included in the licensee's letter dated October 22, 1985.
l 1
We have determined that the manual actions proposed by the licensee are an l
acceptable set of compensatory measures to offset the lack of automatic t
initiation of SGTS for a limited period of time.
l Recent operating events at other BWRs have involved the inadvertent lowering of the water level in the reactor vessel during plant shutdown, typically due to valve misalignments during operations or testing that have led to a drainage path from the reactor vessel to the suppression pool. These events suggest that care should be taken during such operations to monitor vessel water level and preparations should be made to provide appropriate isolation and to initiate injection of water to makeup for any drainage.
To address this concern the staff questioned the licensee regarding the
-remaining operable water level instruments, installed alam features and l
water in.iection systems. TwotypesofinstrumentsthathaveindicatIons i
in the control room will be operable. These are the fourth and fifth types i
described earlier, the narrow range and wide range GE/MAC channels. Either i
narrow range channel can be selected to provide the water level input to the i
flow / level recorder, which provides an alarm if the water level falls to +146 l
inches. By written instruction, the "A" channel has been selected. The "O" l
narrow range channel has been temporarily fitted with a separate alam, also i
set at +146 inches. Thus redundant alarms are being provided.
The licensee has agreed to test these low-level alarms prior to the modification and to direct the reactor operators to initiate manuall would have been initiated automatically at " low y most of the systems that low" level if any of the remaining operable level instruments indicate at or below the low level setpoint value.
This action was implemented by a special written directive to the reactor operators and is included in the licensee's letter of October 22, 1985.
This manual initiation includes:
1.
Core spray 2.
Reactor' isolation 3.
Primary and secondary containment isolation 4.
Recirculation pumps trip 5.
SGTS initiation 6.
RCWI isolation 7.
Shutdown cooling isolation 8.
RBCCW to drywell isolation 9.
Air /N2 to drywell isolation
- 10. Emergency. diesel generator start Further, the Itcensee has committed to maintain the two trains of core spray and the fire protection system operable and to demonstrate these systems operable on a weekly basis. This will provide additional sourcos for water to the core than is required by the TSs. We have reviewed these systems and found them to be appropriate and sufficient.
The staff raised a question regarding the accuracy of the " hot-calibrated" narrow range GE/MAC channels when being operated under cold conditions.
The licensee responded that engineering calculations indicate that during cold operations the hot-calibrated narrow range instruments would be in error by only 0.6 of 1 inch.
In discussing this question with people experienced at other BWRs, the staff got reports that the error to be expected may be 6 to 10 inches and that the Yarway instruments could deviate from the hot-calibrated GE/MAC instruments by as much as 27 to 40 inches.
In subsequent discussions, the licensee indicated that, with the plant at hot full power conditions, the cold-calibrated wide range GE/MAC channels currently indicated 126 inches while the hot calibrated narrow-range GE/MAC channels indicate 160 inches, a difference of 34 inches. The licensee stated also that its experienced reactor operators report that during cold operations, the hot-calibrated narrow range GE/MAC channels will typically agree with the cold-calibrated wide range GE/MAC within 10 inches.
The narrow range and wide range GE/MAC channels were calibrated by the licensee in the last week before sfutdown.
The licensee has agreed to take data and plot the responses of the level instruments during the plant cooldown to verify the indications corresponding to the actual values of +138 and +86 inches, the " low" and " low-low" setpoints.
The operator will te alerted by the alarm at +146 inches and will act if any of the GE/MAC channels (narrow or wide range) reach the value corresponding "
to the " low" setpoint. The span of 52 inches between the " low" and " low-low setpoints is adequate to accommodate errors in instrument indications between
" hot" and " cold" conditions.
Therefore, this question is resolved to an i
accepable degree.
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6-Based upon considerations of the indications and alanns available to the operator and the licensee's comitment to initiate certain systems (listed above) at the " low" setpoint of ECCS, we find that the concern regarding inadvertent lowering of the water level has been adequately addressed.
On a one-time basis for a limited period not to exceed the Cycle 10M outage, we conclude that the licensee's proposed manual actions described above are sufficient compensatory measures to offset the lack of automatic actuation from the reactor water level instrumentation.
Further, the actions the licensee has comitted to, described above, including the increased availability of the core spray and the fire protection system are adequate to address the sossibility of an inadvertent lowering of water level in the vessel during t11s period. Our overall conclusion is therefore that the TS change is acceptable and that the planned modifications can be performed with no undue hazard to the public health and safety during the Cycle 10M outage.
3.1 Findings of Emergency Warranting An Amendment Without Notice The licensee shut down Oyster Creek on October 18, 1985, to begin the Cycle 10M outage.
This outage is scheduled to last a month to complete the remaining environmental qualification modifications of electrical equipment important for safety. These mndifications are required to be completed by November 30, 1985, per 10 CFP 50.49(g) and the staff's letter of March 30, 1985.
One modification to be completed in this outage under cold shutdown conditions is to replace the low-low reactor water level protective instrumentation. The instrumentation will be inoperable during the modification to complete the work within the scheduled outage.
The work on this modification is expected to take 24 days or about 80% of the outage.
The existing TS require this instrumentation to be operable in the shutdowi condition.
If the instrumentation is inoperable, the TS require the Reactor Building to be isolated and the SGTS to be operating.
The licensee stated that isolating the Reactor Building and operating the SGTS will result in undesirable working conditions because of higher butiding air terperature, poor building air quality and higher building air contamination.
It stated that working under these environmental conditions for this length of time will delay the completion of the outage and the scheduled restart of Oyster Creek because the building conditions will prevent the work in the Peactor Butiding to be completed as scheduled. This includes other work being done in the outage in addition to that on this instrumentation. The licensee stated also that the need for this request first became apparent within the last few weeks during the process of planning for the work to replace the instrumentation.
This statement was clarified by the licensee in a phone call on October 14, 1985, to mean the 11 days prior to October 11, 1985.
l The staff has reviewed the circumstances associated with the licensee's request and has discussed this with the NRC Pesident inspectors at Oyster Creek. The staff and the NRC Pesident Inspectors agree with the licensee that the conditions in an isolated Peactor Building with operating the SGTS would be adverse working conditions and could delay the completion of the outage and, therefore, delay the restart of Oyster Creek. The i
requested amendment which is the subject of this safety evaluation is needed to avoid a delay in the scheduled restart of Oyster Creek and thus is an emergency amendment.
The NRC Resident inspectors provided the NRC Oyster Creek Project Manager with copies of two memoranda written by the site licensing manager in August and September 1985. These were on interpretations of the TS relative to the Cycle 10M outage for the low-low reactor water level instrumentation. The Oyster Creek Project Manager concluded that these memoranda did not deal with the issue in the licensee's application. The N#C Resident Inspectors did not disagree with this conclusion.
The staff has concluded that the licensee has prov< ded a sufficient basis for finding that the emergency situation could not have been avoided by prior application.
Therefore, in accordance with 10 CFR 50.91(a)(5), a valid emergency exists.
3.2 Final No Significant Harards Consideration Detemination The five types of reactor water level instrumentation are described in Section 2.0 of this evaluation. The sroposed action wf11 leave only the fourth and fifth types operable during tie modification: These are the narrow range and wide range GE/MAC channels. The narrow range channels include two alarms at an indicated level of +146 inches.
These will be tested prior to the modi fica tion.
The Yarway channels which are being disabled would have provided automatic actuation at the the low-low level setpoint of +86 inches. The control room operators are to initiate manually at low reactor level most of the systems that would have been initiated automatically at low-Iow level by the Yarway channels. The systems to be operated manually are listed to Section 3.0.
The staff has reviewed these systems and concludes that these systems are the only ones that need to be initiated because the station will be in the shutdown condition.
One of these systems is core spray which will add water to the reactor vessel.
The Itcensee will have both trains of core spray operable during the modification.
In addition the fire protection system will be available and operable and these systems will be demonstrated to be operable on a weekly basis, i
On the question of accuracy of the narrow range and wide range GE/MAC channels in Section 3.0, the licensee has agreed to take data and plot water level indicated by the Yarway and GE/MAC channels during cooldown to verify the channel indications corresponding to the actual water level values of +138 and +86 inches, the low and low-low level setpoints. The operator will be alerted by the alams at +146 inches and will manually initate the systems if any of the GE/MAC channels reach the level value corresponding to the 10 level setpoint. The span of 52 inches between the low and low low level setpoints is adequate to acconeodate for errors in the instruments and the i
time for manual action for the operators to act.
l On the question on whether the SGTS could re establish an adequate negative pressure in the Peactor But1 ding if the normal building ventilation system were to become disabled, the licensee conmitted to manually initiate the i
SGTS in the event the nomal bJilding ventilation failed and cannot be i
restarted imediately.
In sum, the staff has reviewed the use of the narrow range and wide range GE/MAC channels as an indication and as a means for taking corrective action in the case of loss of water from the vessel and has concluded these channels with verification of the channel indication corresponding to the lo and 10-10 level setpoints should provide level indication and system initiation essentially equivalent to that provided by the Yarway channels for the licensee to do the modification as planned.
Because the licensee's ability to detect and to respond to lo water level is not substantially)affected, therefore, authorizing this proposed change to TS Table 3.1.1 (1 does not involve a significant increase in the probability or consequences of a previously evaluated accident (2) does not create the possibility of a new or different kind of accident from any accident previously evaluated and (3) does not involve a significant reduction in a margin of safety.
Based on this, the staff concludes that the requested action does not involve a significant hazards consideration.
3.3 State Consultation in accordance with the Commission's regulations, consultations were held with the State of New Jersey, Bureau of Radiation Protection, by telephone on October 15 and 18, 1985.
The State of New Jersey stated that the staff had addressed its concerns and, therefore, it was in agreement with the licensee's proposed amendment.
No other comments were solicited or received. A notice of the proposed amendment was not sublished in the Federal Register due to the lack of sufficient time for pu)lic comment prior to the Friday, October 18, 1985, date on which the licensee requested the amendment to be authorized.
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4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20. The staff has detennined that the araendment 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 finding that this amendment involves no significant hazards consideration. Accordingly, this amendment meets the eli for categorical exclusion set forth in 10 CFR 51.22(c)(9)gibility criteria i
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.
5.0 CONCLUSION
On a one time basis only for the Cycle 10M outage, the staff concludes that the licensee's proposed manual actions described above are sufficient compensatory measures to offset the lack of automatic actuation of SGTS.
Further, the actions the licensee has committed to, described above, including the increased availability of the core spray and the fire protection system are adequate to address the )ossibility of an inadvertent lowering of water level in the vessel during tifs period.
9-The staff has therefore concluded, based on the considerations discussed above, that:
(1) the amendment does not (a) significantly increase the robability or consequences of an accident previously evaluated, p(b) create the possibility of a new or different kind of accident from any previously evaluated or (c) significantly reduce a safety margin and, therefore, the amendment does not involve significant hazards considerations; (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.
6.0 ACKNOWLEDGEMENT This evaluation was prepared by J.T. Beard and J. Donohew.
Dated: November 19, 1985 t
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