ML20085K339
| ML20085K339 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 06/08/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20085K334 | List: |
| References | |
| NUDOCS 9506230298 | |
| Download: ML20085K339 (9) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 133 TO FACILITY OPERATING LICENSE NO. DPR-19.
AMENDMENT NO.127 TO FACILITY OPERATING LICENSE NO. DPR-25.
AMENDMENT NO.154 TO FACILITY OPERATING LICENSE NO. DPR-29.
AND AMENDMENT N0.150 TO FACILITY OPERATING LICENSE NO. DPR-30 COMMONWEALTH EDISON COMPANY m
IOWA-ILLIN0IS GAS AND ELECTRIC COMPANY j
DRESDEN NUCLEAR POWER STATION. UNITS 2 AND 3 00AD CITIES NUCLEAR POWER STATION. UNITS 1 AND 2 DOCKET NOS. 50-237. 50-249. 50-254 AND 50-265
1.0 INTRODUCTION
By letter dated October 15, 1992, as supplemented by letter dated March 9, 1993, Commonwealth Edison Company (Comed, the licensee) submitted an amendment requesting to upgrade Section 3/4.4, " Standby Liquid Control System" of the Dresden Nuclear Power Station, Units 2 and 3, and the Quad Cities Nuclear i
Power Station, Units I and 2, Technical Specifications (TS).
The changes have been requested as part of their Technical Specification Upgrade Program (TSUP).
As a result of findings by a Diagnostic Evaluation Team inspection performed by the NRC staff at the Dresden Nuclear Power Station in 1987, Comed made a decision that both the Dresden Nuclear Power Station and sister site Quad Cities Nuclear Power Station, needed attention focused on the existing custom TS used at the sites.
The licensee made the decision to initiate a TSUP for both Dresden and Quad Cities. The licensee evaluated the current TS for both stations against the Standard Technical Specifications (STS) contained in NUREG-0123, " Standard Technical Specifications General Electric Plants BWR/4, Revision 4."
Both Dresden and Quad Cities are BWR-3 designs and are nearly identical plants.
The licensee's evaluation identified numerous potential improvements such as clarifying requirements, changing the TS to make them more understandable and to eliminate the need for interpretation, and deleting requirements that are no longer considered current with industry practice. As a result of the 9506230298 950600 DR ADOCK 05000237 PDR
. evaluation, Comed elected to upgrade both the Drosden and Quau Cities TS to the STS contained in NUREG-0123.
The TSUP for Dresden and Quad Cities is not a complete adoption of the STS.
The TSUP focuses on (1) integrating additional information such as equipment operability requirements during shutdown conditions, (2) clarifying requirements such as limiting conditions for operations and action statements utilizing STS terminology, (3) deleting superseded requirements and modifications to the TS based on the licensee's responses to Generic Letters (GL), and (4) relocating specific items to more appropriate TS locations.
The application dated October 15, 1992, as supplemented March 9, 1993, proposed to upgrade only the section of the TS to be included in TSUP section 3/4.4, " Standby Liquid Control System" of the Dresden and Quad Cities TS.
The staff reviewed the prorned changes and evaluated all deviations and changes between the proposed TS, the STS, and the current TS.
In no case did the licensee propose a change in the TS that would result in the relaxation of the current design requirements as stated in the Updated Final Safety Analysis Reports (UFSAR) for Dresden or Quad Cities.
In response to the staff's recommendations, the licensee submitted identical TS for Quad Cities and Dresden except for plant-specific equipment and design differences.
Technical differences between the units are identified as appropriate in the proposed amendment.
2.0 EVALUATION Review Guidelines - The licensee's purpose for the TSUP was to reformat the existing Dresden and Quad Cities TS into the easier to use STS format.
Plant specific data, values, parameters, and equipment specific operational requirements contained in the current TS for Dresden and Quad Cities were retained by the licensee in the TSUP.
The STS contained in NUREG-0123 were developed by the NRC and industry because of the shortcomings associated with the custom TS which were issued to plants licensed in early 1970's (i.e., Dresden (1971) and Quad Cities (1972)). The STS developed by the NRC and industry provided an adequate level of protection for plant operation by assuring required systems are operable and have been proven to be able to perform their intended functions. The limiting conditions for operation (LCO), the allowed out-of-service times, and the required surveillance frequencies were developed based on industry operating experience, equipment performance, and probabilistic risk assessment analysis during the 1970's.
The STS were used as the licensing basis for plants licensed starting in the late 1970's.
For the most part, Comed's adoption of the STS resulted in more restrictive LCOs and surveillance requirements (SR).
In some cases, however, the STS provides relief from the Dresden and Quad Cities current TS requirements.
In all these cases, the adoption of the STS requirements for LCOs or SR does not
. change the current design requirements of either plant as described in the UFSAR.
In addition, the success criteria for the availability and operability of all required systems contained in the current TS are maintained by the adoption of the STS requirements in the proposed TSUP TS.
In addition to adopting the STS guidelines and requirements in the TSUP, Comed has also evaluated Generic Letters (GLs) concerning line item improvements for TS.
These GLs were factored into TSUP to make the proposed TS in the TSUP reflect industry lessons learned in the 1980's and early 1990's.
Deviations between the proposed specifications, the STS, and the current TS were reviewed by the staff to determine if the deviations were due to plant specific features or if they posed a technical deviation from the STS guidelines.
Plant specific data, values, parameters, and equipment specific operational requirements contained in the current TS for Dresden and Quad Cities were retained by the licensee in the upgraded TS.
Administrative Chanaes - Non-technical, administrative changes were intended to incorporate human factor principles into the form and structure of the STS so that they would be easier for plant operation's personnel to use. These changes are editorial in nature or involve the reorganization or reformatting of requirements without affecting technical content of the current TS or operational requirements.
Every section of the proposed TS reflects this type of change.
More Restrictive Reauirements - The proposed TSUP TS include certain more restrictive requirements than are contained in the existing TS.
Examples of more restrictive requirements include the following:
placing an LCO on plant equipment which is not required by the present TS to be operable; adding more restrictive requirements to restore inoperable equipment; and adding more restrictive surveillance requirements.
Less Restrictive Reauirements - The licensee provided a justification for less restrictive requirements on a case-by-case basis as discussed in this SE.
When requirements have been shown to provide little or no safety benefit, their removal from the TS may be appropriate.
In most cases, these relaxations had previously been granted to individual plants on a plant-specific basis as the result of (a) generic NRC actions, and (b) new NRC staff positions that have evolved from technological advancements and operating experience.
The Dresden and Quad Cities plant design was reviewed to determine if the specific design basis was consistent with the STS contained in NUREG-0123.
All changes to the current TS and deviations between the licensee's proposed TS and the STS were reviewed by the staff for acceptability to determine if adequate justification was provided (i.e., plant specific features, retention of existing operating values, etc.).
Deviations the staff finds acceptable include:
(1) adding clarifying statements, (2) incorporating changes based on GL, (3) reformatting multiple i
4-steps included under STS action statements into single steps with unique identifiers, (4) retaining plant specific steps, parameters, or values, (5) moving ACTION statements within a TS, (6) moving ACTION statements from an existing TS to form a new TS section, and (7) omitting the inclusion of STS steps that are not in existing TS.
Relocation of Technical Specifications - The proposed TS include the relocation of some requirements from the TS to licensee-controlled documents.
Section 182a of the Atomic Energy Act requires applicants for nuclear power plant operating licenses to state Technical Specifications to be included as part of the license. The Commission's regulatory requirements related to the content of TS are set forth in 10 CFR 50.36. That regulation requires that the TS include items in five specific categories, including (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls. However, the regulation does not specify the particular requirements to be included in a plant's TS.
The Commission has provided guidance for the contents of TS in its " Final Policy Statement on Technical Specification Improvements for Nuclear Power Reactors," 58 Fed. Reg. 39132 (July 22,1993), in which the Commission indicated that compliance with the Final Policy Statement satisfies Section 182a of the Energy Reorganization Act.
The Final Policy Statement identified four criteria to be used in determining whether a particular matter is required to be included in the TS, as follows:
(1) Installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary; (2) a process variable, design feature, or operating restriction that is an initial condition of a Design Basis Accident or Transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (3) a structure, system, or component that is part of a primary success path and which functions or actuates to mitigate a Design Basis Accident of Transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (4) a structure, system, or component which operating experience or probabilistic safety assessment has shown to be significant to public health and safety. As a result, existing TS requirements which fall within or satisfy any of the criteria in the Final Policy Statement must be retained in the TS, while those TS requirements which do not fall within or satisfy these criteria may be relocated to other, licensee-controlled documents.
The following sections provide the staff's evaluations of the specific proposed TS changes.
3.0 EVALUATION OF TSUP PROPOSED TS SECTION 3/4.4. " STANDBY LIOUID CONTROL SYSTEM" The following sections provide the staff's evaluation of the TS changes reflected in proposed TSUP TS Section 3/4.4, " Standby Liquid Control System (SLCS)." Proposed TSUP TS Section 3/4.4 assures the availability of a
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. reactivity control system independent of the control rods during power operation and during cold shutdown with any control rod withdrawn.
3.1 LCO and Applicability Proposed TS 3.4.A. " Standby Liquid Control System," incorporates the requirements of STS Section 3.1.5 and current TS requirements from Section 3.4.
The current TS for Dresden and Quad Cities require that the SLCS be operable during periods when fuel is in the reactor except when the reactor is in cold shutdown and all control rods are fully inserted and Specification 3.3.A is met. The proposed TS state that the LC0 applies to modes 1 and 2, and to mode 5 when any control rod is withdrawn.
The proposed applicability statement is consistent with STS. The proposed applicability statement requires that SLCS be operable in operational modes where control rods can be withdrawn.
SLCS is not required in modes 3 or 4 because the control rods are fully inserted.
The proposed TS applicability is equivalent to the current provisions, but is more clearly defined. The proposed applicability statement is an enhancement of the current TS and is consistent with the STS and is, therefore, acceptable.
3.2 Actions Proposed TS 3.4.A Action 1 incorporates the requirements of current TS 3.4.B and 3.4.0 and STS 3.1.5 Action a.
Proposed TS Action 1 requires that, with one SLCS subsystem inoperable in modes 1 or 2, the inoperable subsystem must be restored to operable status within 7 days or the unit must be in hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. This is similar to the current TS except that the current TS require cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the allowed outage time is exceeded.
If SLCS is inoperable, it is not necessary to bring the plant to cold shutdown. Once the control rods have been successfully inserted into the reactor core, which is achieved in Mode 3 " Hot Shutdown", the SLCS is no longer needed because control rod insertion provides adequate reactivity control.
The current TS requirement to take the reactor to cold shutdown when SLCS is inoperable is not required and results in unnecessary thermal cycles on the reactor vessel. The staff finds eliminating the requirement to take the reactor to Cold Shutdown is acceptable. Therefore, this change from the current TS is acceptable.
The current TS Section 3.4 does not specify action to be taken when both subsystems of SLCS are inoperable.
If both subsystems of SLCS became inoperable, under the current TS the unit would be required to enter Section 3.0.A of the current TS and be in hot shutdown in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and cold shutdown in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
If both subsystems are inoperable, the proposed TS require one subsystem to be restored within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed TS, therefore, is a relaxation of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to begin entering hot shutdown.
The proposed allowed outage time is a reasonable period of time to attempt repairs bafore initiating a potentially unnecessary shutdown.
The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> allowed outage time is based on operating experience at other sites, will not significantly increase the probability or consequences of an accident, and is consistent with STS. The proposed TS provide a
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. clarification and the relaxation of current TS will not reduce the current safety limits.
Therefore, the proposed Action 1 is acceptable.
Proposed TS 3.4.A Action 2 incorporates the requirements of current TS 3.4.B and 3.4.0 and STS 3.1.5 Action b.
Action 2 requires that, with one subsystem inoperable in mode 5 with any control rod withdrawn, the inoperable subsystem must be restored to operable status within 30 days or all insertable control rods must be inserted within I hour. With both subsystems inoperable, all insertable control rods must be inserted within I hour. The current TS do not separate the provisions for operational modes 1 and 2 from those of operational mode 5.
Therefore, the current TS allow only a 7 day LCO under i
these circumstances.
In operational mode 5, the SLCS is not as likely to be required to perform an accident mitigation function as in operational modes 1 or 2 since only one control rod can be withdrawn when refueling interlocks are active. Therefore, for operational mode 5, 30 days is allowed to restore an inoperable subsystem.
This action is consistent with STS.
The proposed TS addresses the actual plant conditions and is, therefore, an enhancement over the current TS which are overconservative for mode 5.
The proposed TS are more conservative than current TS in mode 5 when both subsystems are inoperable because action is required within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to insert all control rods whereas the current TS do not address this situation.
The staff has determined that, based on the above evaluation, al increase in the A0T to 30 days for mode 5 will not reduce the current safety limits. Therefore, the proposed Action 2 is acceptable.
4 Current TS 4.4.B requirts that when a component becomes inoperable, its redundant component shall be demonstrated operable immediately and daily l
thereafter. The requirement has been eliminated in the proposed TS.
This change is consistent with the guidelines of NUREG-Oli3, the new improved STS in NUREG-1433, " Improved BWR-4 Technical Specifications," dated September 1992 and GLs 93-04 and 94-01.
Industry practice has shown that demonstrating opposite train equipment operable through additional surveillance reduces system reliability.
Therefore, the staff finds discontiauing the opposite subsystem verification acceptable.
3.3 Surveillance Requirements Proposed TS 4.4.A.I.b requires verification that the voluw of sodium pentaborate solution is greater than or equal to the limits of Figure 3.4.A-1, Sodium Pentaborate Concentration Versus Minimum Gross Volume.
This proposed TS is consistent with current TS 4.4.C.2.
STS 4.1.5.a.2 specifies a number of gallons of sodium pentaborate solution that must be present.
The proposed TS deviate from STS by varying the required volume according to temperature.
By maintaining the minimum equivalent solution, the licensee believes a wider operating range can be achieved by varying the concentration of the sodium pentaborate decahydrate from 14 to 16.5 percent inside the SLCS storage tank.
This requirement is more conservative than the STS.
Therefore, the staff finds the deviation from the STS to be acceptable.
- Proposed TS 4.4.A.l.c requires that the heat tracing circuit be verified operable every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by determining the temperature of the pump suction to 1
M greater than or equal to 83 degrees Fahrenheit. The current TS do not santain this requirement. The proposed SR incorporates the requirements of STS 4.1.5.a.3.
This change is an enhancement of the current TS and is acceptable.
Proposed TS 4.4.A.2.a requires that the licenses verify the continuity of tha explosive charge once per 31 days. This requirement is not in the current TS and incorporates the requirements of STS 4.1.5.b.1.
This change is an enhancement of the current TS and is acceptable.
Proposed TS 4.4.A.2.c requires that each valve in the flow path that is not locked or otherwise secured in position, be verified to be in its correct position every 31 days. This requirement is not in current TS.
It incorporates the requirements of STS 4.1.5.b.3.
This change is an enhancement of the current TS and is acceptable.
Proposed TS 4.4.A.3 requires that, when the pumps are tested pursuant to 1S Section 4.0.E, the pumps must meet a minimum flow requirement of 40 gpm per pump at a pressure of greater than or equal to 1275 psig.
The proposed TS refers to TS 4.0.E which states that surveillance requirements for inservice testing (IST) be performed Et the frequency specified by Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code except where relief has been granted by the Commission.
This deviates from current TS 4.4.A.1 which requires that this test be performed every 31 days.
The SLCS pumps are currently incitded in thr, IST program.
The current IST j
required test frequency for the SLCS pumps is also 31 days, therefore the test frequency does not change.
Proposed iS 4.4.A.3 does not change v y requirements but, rather, indicates that the testing frequency wi b in accordance with the IST program by reference to TS 4.0.E.
Revision. to the IST program are controlled by the requirements of 10 CFR 50.55a.
Tne staff finds that sufficient regulatory controls exist under 10 CFR 50.55a to assure I
i continued protection of the public health and safety.
This requirement is consistent with STS 4.1.5.c.
Based on the above evaluation, the staff finds that the relocation of this requirement from the TS is acceptable.
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Proposed TS 4.4.A.4 incorporates the requirement of current TS 4.4.A.2.b.
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current TS requires that every 18 months two explosive charges be exploded out of a six charge batch.
In addition, the explosive operated shear plug valve is disassembled and checked. The proposed TS requires that every 18 months a complete activation of the shear plug valve be initiated and water passed i
through the valve into the reactor vessel.
The valve is then reset and the explosive charge is replaced from the same batch. The proposed TS is more i
conservative than the current TS because complete valve operation, including operation of the explosive charge in the valve and water flow through the valve into the reactor vessel, is verified as opposed to separate testing of 2
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t t t the explosive charges and the valve disassembly. Therefore, the staff finds the deviation between the current TS and the proposed TS to be acceptable.
Proposed TS 4.4.A.4.c requires demonstration that the pump suction line from the storage tank is not plugged by manually initiating the system, except the explosive valves, and pumping solution in the recirculation path every 18 months. This SR deviates from STS 4.1.5.d.3 because the STS requirement applies to a system design which is inconsistent with that at Dresden or Quad Cities. The STS requires a demonstration that the heat traced piping between the storage tank and the reactor vessel is unblocked by pumping solution from the storage tank to the test tank, The licensee does not incorporate heat traced piping up to the reactor vessel nor a test tank in the recirculation path. The proposed TS Section 4.4.A.4.c adequately demonstrates the operability of the system design and meets the intention of the STS guidelines.
Therefore, the staff finds that the licensee has met the intent of the STS and the deviation is acceptable.
3.4 Technical Soecification Bases The staff has reviewed the proposed Bases for TS 3/4.4.
The propost;d Bases have been prepared using tne guidelines of the STS. The staff finds these proposed Bases acceptable.
3.5 Conclusion The changes in proposed TS 3/4.4, " Standby Liquid, 4 il System" do not adversely affect the safe operation of Dresden and Quad Cities Station. The proposed TS clarifies the requirements of the present TS through the adoption of STS format (where practical), adds more restrictive requirements, and incorporates changes to correct inconsistencies with the STS.
Based on the above evaluation, the staff finds the proposed TS 3/4.4 acceptable.
4.0
SUMMARY
The proposed TS for Section 3/4.4 will be clearer and easier to use as a result of the adaptation of the STS format. The changes result in additional limitations, restrictions, or changes based on generic guidance.
It is the staff's assessment that the changes proposed in this amendment do not pose any decrea:e in safety, or an increase in the probability of an analyzed or unar.alyzed accident. The revised TS changes do not reduce the existing margin of safety set forth by the current TS. Therefore, the staff finds the proposed TS changes acceptable.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State off kial was notified of the proposed issuance of the amendments. The State official had no comments.
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6.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The NRC staff has determined that the amendments involve no significant increase in the amounts, and no i
significant change in the types, of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (58 FR 36429). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR SI.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
7.0 CONCLUSIDN l
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
J. Stang/ D. Skay Date:
June 8, 1995 I
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