ML20087A125
| ML20087A125 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/26/1995 |
| From: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20087A128 | List: |
| References | |
| 95-377, NUDOCS 9508040184 | |
| Download: ML20087A125 (13) | |
Text
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VIHOINIA ELucTule Axn Pownu Coxl>m Itsennonn,VsuormA count i
July 26,1995 U.S. Nuclear Regulatory Commission Seria! No.95-377 j
Attention: Document Control Desk NL&P/JBL R0 Washington, D.C. 20555 Docket Nos.
50-338 50-339 License Nos. NPF-4 NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGES Pursuant to 10 CFR 50.90, the Virginia Electric and Power Company requests amendments, in the form of changes to the Technical Specifications, to Facility Operating Ucense Numbers NPF-4 and NPF-7 for North Anna Power Station Units 1 and 2, respectively. The proposed changes would clarify the Technical Specifications to allow switching of charging and low-head safety injection pumps during unit shutdown conditions. The proposed changes would also allow additional methods of rendering these same pumps incapable of injecting into the reactor coolant system when required for low-temperature conditions.
A discussion of the proposed Technical Specifications changes is provided in.
The proposed Technical Specifications changes are provided in.
It has been determined that the proposed Technical Specifications changes do not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92. The basis for our determination that the changes do not involve a significant hazards considsration is provided in Attachment 3. The proposed Technical Specifications changes have been i
reviewed and approved by the Station Nuclear Safety and Operating Committee and the Management Safety Review Committee.
Should you have any questionc or require additional information, please contact us.
Very truly yours, 1co James P. O'Hanlon Senior Vice President - Nuclear Attachments (1
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95o804o184 950726 PDR ADDCK 0500o338
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' U.S.' Nuclear Regulatory Commission oc:
' Region II -
101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. R. D. McWhorter NRC Senior Resident inspector North Anna Power Station Commissioner Department of Radiological Health Room 104A 1500 East Main Street Richmond, Virginia 23219 i
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COMMONWEALTH OF VIRGINIA )
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COUNTY OF HENRICO
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The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. P. O'Hanlon, who is Senior Vice President -
Nuclear, of Virginia Electric and Power Company. He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the-
' document are true to the best of his knowledge and belief.
Acknowledged before me this Ala day of b uku
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ATTACHMENT 1 i
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DISCUSSION OF CHANGES VIRGINIA ELECTRIC AND POWER COMPANY s
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Riggyssion of Chan9fta introduction The North Anna Units 1 and 2 Technical Specifications require periodic surveillance testing of the charging and the low-head safety injection (LHSI) pumps during plant operating and shutdown conditions.
However, during normal plant shutdown conditions, the current Technical Specifications are unnecessarily restrictive with respect to switching'of these pumps for maintenance and testing activities. The Technical Specifications require one pump, and only one pump, to be operable during low-temperature operating conditions.
This literal reading of the Technical Specifications creates an operational constraint which, if adhered to, would result in the inability to swap pumps. Similarly, the remaining pumps are currently required to be rendered inoperable by placing their cont,ol switches in the pull-to-lock position.
Alternative methods of rendering pumps inoperable are available which provide equivalent protection against inadvertent overpressurization of the reactor coolant
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system (RCS), yet also provide additional operational flexibility. Therefore, Virginia Electric and Power Company proposes to clarity North Anna Units 1 and 2 Technical Specifications 3/4.1.2.3, 3/4.1.2.4, 3/4.5.3 and their associated Bases to be consistent with actual operating practices for pump switching evolutions during shutdown i
conditions.
These proposed changes eliminate ambiguity and any need for interpretation of these specifications. The proposed changes also include several administrative / editorial changes to Technical Specifications 3/4.1.2.3, 3/4.1.2.4, 3/4.5.2,3/4.5.3, and some of the associated Bases.
The proposed changes to the North Anna Units 1 and 2 Technical Specifications will not adversely affect the safe operation of the plant. In addition, these proposed changes will not result in an unreviewed safety question as defined in the criteria of 10 CFR 50.59.
Backscoultd Each unit at the North Anna Power Station is equipped with three charging pumps and two low-head safety injection (LHSI) pumps. The charging pumps provide inventory control, normal boration to the RCS, and injection flow to the reactor coolant pump seals. The charging pumps also act as the high-head safety injection (HHSI) pumps during certain accident conditions. The LHSI pumps provide lower-pressure, high-Page 1 of 8
volume inventory control during emergency conditions.
However, the current Technical Specifications associated with operation of the charging pumps and LHSi
. pumps during low-temperature operating conditions do not allow sufficient latitude for pump switching. This operationalinflexibility is particularly of concern for the charging pumps because the operating charging pump is providing seal injection flow to the reactor coolant pumps. Isolation of the in-service charging pump from the RCS prior to establishing a flow path from another charging pump is undesirable because it would result in a momentary loss of seal injection to the reactor coolant pumps and isolate the RCS makeup source. The momentary loss of seal injection to a running reactor coolant pump would unnecessarily increase the probability of reactor coolant pump seal damage.
The preferred method of switching charging pumps without a temporary loss of reactor coolant pump seal injection flow involves placing a second pump in its recirculation flow path and running the pump for a short period of time to establish normal operating temperature and verify adequate discharge pressure. The second pump is then ahgned to the RCS and the first pump isolated and rendered inoperable. A literal reading of the current Technical Specifications requirements prohibits this method of pump switching without relying on the provisions of the associated action statement.
Specifically, with the RCS temperature less than 235 F (270oF for Unit 2) in Mode 4,5, and 6 (when the head is on the reactor vessel), the Technical Specifications require that one, and only one, charging pump shall be operable and capable of injecting into the RCS. Although these Technical Specifications restrictions are intended to address a low-temperature overpressure protection (LTOP) concern, a conservative interpretation of these requirements could preclude the starting of a second pump to facilitate swapping charging pumps during these modes of operation.
Similarly, during normal plant shutdown conditions, it is necessary to render two of the three charging pumps and one of the two LHSI pumps inoperable to maintain the LTOP design bases assumptions. This requirement limits the number of pumps capable of injecting water into the RCS and, thus, provides assurance that an inadvertent mass addition pressure transient can be relieved by the operation of a single pressurizer power-operated relief valve (PORV). Currently, the Technical Specifications require that the pumps be rendered inoperable by placing their control switches in the pull-to-lock position.
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Rendering a charging pump or LHSI pump inoperable can be accomplished by methods other than placing the control switch in the pull-tolock position, such as opening and tagging (i.e., placing the breaker under administrative control) of the power supply breaker or closing of the pump discharge valve (s). Any of these methods ensure that the affected pump is no longer capable of injecting water into the RCS. Utilizing the pump discharge valve isolation method for rendering a charging pump inoperable would also allow surveillance and post-maintenance testing of an inoperable pump by allowing it to be run on a recirculation flow path. The recirculation flow path does not inject water into the RCS.
Discussion N UREG-1431, Revision 1, improved Standard Technical Specifications for Westinghouse Plants, was reviewed to determine how the issues are addressed in the improved specifications. The corresponding NUREG-1431, Rev.1, Limiting Condition for Operation is LCO 3.4.12. Action B for this LCO has a modifying note which states that more than one charging pump may be capable of injecting into the RCS for pump switching operations. North Anna proposes to add similar footnotes to the applicable specifications for the Unit 1 and Unit 2 Technical Specifications and enhance the applicable portions of the Technical Specifications Bases.
Justification for allowing two charging pumps or two LHSI pumps to be capable of injecting into the RCS during low-temperature operation is based on the pump switching evo:ution being under the direct administrative control of a licensed operator and being of shor'. duration. Numerous indications are available to the operator that would indicate that an excessive mass addition into the RCS (including safety injection system actuation) was occurring.
These indications include main control board alarms, RCS make-up flow balanced against RCS letdown flow, pressurizer level and pressure indication and RCS pressure indication. If an excessive mass addition were to occur during the pump switching evolution, the operator would be able to immediately assess the plant conditions and take prompt remedial action to prevent any challenges to RCS integrity. Further, administra'.ive controls will ensure that the momentary two-pump-operable pump switching method would not be utilized during water solid conditions.
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l For those specifications that place a limit on the number of operable charging pumps, the current Technical Specifications require that the other charging pumps be rendered inoperable by placing their control switches in the pull-to-lock position. This requirement is too restrictive as other means are available to effectively render a charging pump inoperable.
Rendering a charging pump inoperable can be accomplished by methods such as placing the control switch in the pull-to-lock position, opening and tagging of the power supply breaker, or closing of the pump discharge valve (s). Each of these methods ensures that a charging pump is no longer capable of injecting water into the RCS. Utilizing the isolation of the pump discharge valve method of rendering a charging pump inoperable would also allow surveillance and post-maintenance testing of the inoperable charging pump by allowing it to be run in its recirculation flow path. This recirculation flow path does not inject any water into the RCS. North Anna proposes to delete the specific restriction designating the method to be used for rendering a charging pump inoperable from the specification
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and add guidance in the Technical Specifications Bases for the acceptable alternatives.
4 Additionally, editorial changes are being made as specified below to improve readability, correct previous typographical errors, and for consistency between the Unit 1 and Unit 2 Technical Specifications.
Specific Changes The proposed Technical Specifications changes described herein apply to North Anna Units 1 and 2 unless specified otherwise.
On Unit 1 Technical Specification Index Page V, in the line that reads "3/4.5.2 ECCS SUBSYSTEMS - Tavg 2 350 F," replace the "2" symbol with the phrase
" GREATER THAN OR EQUAL TO."
On Unit 1 Technical Specification Index Page V, in the line that reads "3/4.5.2 ECCS SUBSYSTEMS - Tavg < 350*F," renumber the line as "3/4.5.3" and replace the "<" symbol with the phrase "LESS THAN."
On Unit 2 Technical Specification Index Page V, in the line that reads "3/4.5.2 ECCS SUBSYSTEMS - Tavg GREATER THAN 350 F," add the phrase "OR EQUAL TO" following " GREATER THAN."
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in Technical Specification 3.1.2.3, delete the words "At least" so that the line begins with "One charging pump...."
In the Unit 1 Surveillance Requirement 4.1.2.3.1, delete the words "At least" so that the line begins with "The above required charging pump..." and replace the "2" symbol with the phrase " greater than or equal to."
In Surveillance Requirement 4.1.2.3.1, relocate the comma (,) from following the word " verifying" to after the word "that."
In Surveillance Requirement 4.1.2.3.2, replace the current wording with the following: "At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, verify that a maximum of one charging pump is OPERABLE and capable of injecting into the RCS.*" At the bottom of the page, add the footnote: "* Two charging pumps may be OPERABLE and capable of injecting into the RCS during pump switching operations."
In the Unit 1 Surveillance Requirement 4.1.2.4.1, replace the "2" symbol with the phrase " greater than or equal to."
In the Unit 1 Surveillance Requirement 4.1.2.4.2, replace the current wording with the following: "At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, verify that a maximum of one charging pump is OPERABLE and capable of injecting into the RCS whenever the temperature of one or more of the RCS cold legs is less than or equal to 235 F
- " In the footnote (*) at the bottorn of the page, delete the word " centrifugal."
Also, at the bottom of the page, add the footnote: "** Two charging pumps may be OPERABLE and capable of injecting into the RCS during pump switching operations."
in the Unit 2 Surveillance Requirement 4.1.2.4.2:, replace the current wording with the following: "At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, verify that a maximum of one charging pump is OPERABLE and capable of injecting into the RCS whenever the temperature of one or more of the RCS cold legs is less than or equal to 270 F # #."
In the footnote (#) at the bottom of the page, delete the word
" centrifugal." Also, at the bottom of the page, add the footnote: "## Two charging pumps may be OPERABLE and capable of injecting into the RCS during pump switching operations."
In the Unit 1 Technical Specification 3.5.2. in the subheading that reads "ECCS SUBSYSTEMS - Tavg 2 350=F," replace the "2" symbol with the phrase
" GREATER THAN OR EQUAL TO."
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In the Unit 2 Technical Specification 3.5.2, in the subheading that reads "ECCS SUBSYSTEMS -Tavg GREATER THAN 350 F," add the phrase "OR EQUAL TO" following " GREATER THAN."
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In Technical Specification 3.5.2.a, delete the word " centrifugal."
In Technical Specification Surveillance Requirement 4.5.2.e.2.a, delete the word
" centrifugal."
In Technical Specification Surveillance Requirement 4.5.2.f.1, delete the word
" centrifugal."
In the Unit 1 Technical Specification Surveillance Requirements 4.5.2.f.1 and 4.5.2.f.2, replace the "2" symbol with the phrase " greater than or equal to."
in the Unit 1 Technical Specification 3.5.3, in the subheading that reads "ECCS
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SUBSYSTEMS - Tavg < 350 F," replace the "<" symbol with the phrase "LESS THAN."
In Technical Specification 3.5.3.a, delete the word " centrifugal."
l In Technical Specification 3.5.3, Action "a," delete the word " centrifugal."
In Technical Specification 3.5.3, footnote "#," delete the word " centrifugal" and following the word " OPERABLE" add the phrase, "and capable of injecting into the RCS." Also, at the end of the sentence add the phrase "except two charging pumps may be OPERABLE and capable of injecting into the RCS during pump switching operations."
In Technical Specification Surveillance Requirement 4.5.3.2, replace the current wording with the following: "At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, verify that a maximum of one charging pump and one low head safety injection pump is OPERABLE and capable of injecting into the RCS whenever the temperature of one or more of the RCS cold legs is less than or equal to 235 F." At the bottom of the page, add the footnote: " Two charging pumps may be OPERABLE and capable of injecting into the RCS during pump switching operations."
In the Bases for 3/4.1.3, Boration Systems, on Page B3/4 1-3, in the third paragraph (fourth paragraph for Unit 2), delete the word " centrifugal." Following Page 6 of 8
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that paragraph, add the following as a new paragraph: "Having more than one charging pump OPERABLE during pump switching operations is allowed. This is acceptable based on pump switching being a momentary action under the direct administrative control of a licensed operator.
Rendering a charging pump inoperable for this requirement may be accomplished by methods such as placing the control switch in the pull-to-lock position, tagging of the power supply breaker, or closing of the pump discharge valve (s)."
In the Bases for 3/4.5.2 and 3/4.5.3, ECCS Subsystems, on Page B3/4 5-2,
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replace the second paragraph with the following two paragraphs: (1) "The limitation for a maximum of one charging pump and one low head safety injection pump to be OPERABLE and the Surveillance Requirement to verify that a maximum of one charging pump and one low head safety injection pump is capable of injecting into the RCS below 235 F provides assurance that a mass addition pressure transient can be relieved by the operation of a single PORV."
and (2) " Rendering a charging pump inoperable may be accomplished by methods such as placing the control switch in the pull-to-lock position, tagging of the power supply breaker, or closing of the pump discharge valve (s). Having more than one charging pump OPERABLE and capable of flowing to the RCS during pump switching operations is allowed. This is acceptable based on pump switching being a momentary action under the direct administrative control of a licensed operator."
Relocate the last paragraph at the bottom of the page to the top of the succeeding page preceded by the heading "ECCS SUBSYSTEMS (Continued)."
S_alety_ Significance The proposed changes to the limiting conditions of operation for the charging and LHSI pumps are consistent with NUREG-1431, Revision 1, improved Standard Technical Specifications for Westinghouse Plants. The proposed changes will allow more than one charging pump to be operable and capable of injecting water into the RCS during RCS low-temperature operation for the purpose of conducting pump switching evolutions. Additionally, the methods used for rendering charging pumps and LHSI pumps inoperable will be expanded to include alternate methods such as opening and tagging of the power supply breaker and closing of the pump discharge valve. The acceptance methods of rendering these pumps inoperable will be included the Technical Specifications Bases.
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The proposed Technical Specifications do not affect the probability of occurrence or the consequences of the accidents identified in the UFSAR.
No new accident precursors are being generated by these proposed changes.
Charging pump switching operations will be under the direct administrative control of a licensed operator who will be able to immediately respond to any situation that could result in an excessive mass addition into the RCS. In addition, expanding the Technical Specifications Bases to include alternate acceptable methods of rendering pumps inoperable does not affect the consequences of any accident as previously evaluated in the UFSAR.
The proposed changes will not increase the probability of a malfunction of the charging pumps or the LHSI pumps. These pumps will continue to be operated and tested in a manner that will ensure their capability to perform their intended safety functions.
The margin of safety as described in the Technical Specifications will not be reduced since the charging pump switching operations will be under the direct administrative control of a licensed operator who will be able to immediately respond to any situation tha' could result in an excessive mass addition into the RCS. The alternate methods of rendering pumps inoperable provide the same level of assurance that the pump is incapable of injecting water into the RCS as placing the pump control switch in the
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pull-to-lock position.
Based on the above evaluation, Virginia Electric and Power Company has determined that the proposed changes to the Technical Specifications will not adversely affect the safe operation of the plant. Therefore, this proposed change request for North Anna Units 1 and 2 would not result in an unreviewed safety question as defined in the criteria of 10 CFR 50.59.
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ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGES NORTH ANNA UNITS 1 AND 2 1
VIRGINIA ELECTRIC AND POWER COMPANY l
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