NOC-AE-05001841, License Amendment Request - Proposed Amendment to Technical Specifications 3.4.6.1 and 3.4.6.2

License Amendment Request - Proposed Amendment to Technical Specifications 3.4.6.1 and 3.4.6.2

ML051610216
Person / Time
Site:	South Texas
Issue date:	06/02/2005
From:	Jordan T South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-05001841
Download: ML051610216 (13)

Text

Nuclear Operating Company

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June 2, 2005 NOC-AE-05001841 10CFR50.90 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Units 1 and 2 Docket No. STN 50498 and STN 50499 License Amendment Request -

Proposed Amendment to Technical Specifications 3.4.6.1 and 3.4.6.2 Pursuant to 10 CFR 50.90, STP Nuclear Operating Company (STPNOC) hereby requests an amendment to Technical Specification (TS) 3.4.6.1, "Reactor Coolant System Leakage Detection Systems," to specifically require only one containment radioactivity monitor (particulate channel) is to be operable in Modes 1, 2, 3 and 4. Additionally, corresponding changes to Surveillance Requirement 4.4.6.2.1, "Reactor Coolant System Operational Leakage," are also requested.

Currently, TS 3.4.6.1 states that one containment atmosphere radioactivity monitor (gaseous or particulate) is to be operable. The level of radioactivity in the reactor coolant normally is much lower than the value that was assumed in the Updated Final Safety Analysis Report. As a result, the gaseous channel of the containment atmosphere radioactivity monitor can no longer be used to promptly detect a small reactor coolant system (RCS) leak. However, the particulate channel sensitivity continues to support the licensing basis. Therefore, the proposed amendment specifically requires only the containment radioactivity monitor (particulate channel) to be operable. to this letter provides licensee evaluation including the No Significant Hazards Determination and Attachment 2 provides the TS page marked up with the proposed change.

The associated change to the TS Bases will be made accordingly as a part of the implementation of this license amendment.

The Plant Operations Review Committee has recommended approval of the proposed change.

STPNOC has notified the State of Texas in accordance with 10 CFR 50.91(b).

There are no commitments contained in this license amendment request.

4 I STI: 31837684

NOC-AE-05001841 Page 2 of 3 STPNOC requests approval of the proposed amendment by February 28, 2006. Once approved, the amendment shall be implemented within 90 days.

If there are any questions regarding this proposed amendment, please contact Scott Head at (361) 972-7136 or me at (361) 972-7902.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on 1t Z 5ooS Vice President of Engineering jai/

Attachments:

1. Licensee's Evaluation

2. Proposed Technical Specification Change (Mark-up)

STI:31837684

NOC-AE-05001841 Page 3 of 3 cc:

(paper copy) (electronic copy)

Bruce S. Mallett A. H. Gutterman, Esquire Regional Administrator, Region IV Morgan, Lewis & Bockius LLP U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 David H. Jaffe Arlington, Texas 76011-8064 U. S. Nuclear Regulatory Commission Richard A. Ratliff Jack A. Fusco Bureau of Radiation Control Michael A. Reed Texas Department of State Health Services Texas Genco, LP 1100 West 49th Street Austin, TX 78756-3189 Jeffrey Cruz C. Kirksey U. S. Nuclear Regulatory Commission City of Austin P. 0. Box 289, Mail Code: MN1 16 Wadsworth, TX 77483 Jon C. Wood Cox Smith Matthews C. M. Canady J. J. Nesrsta City of Austin R. K. Temple Electric Utility Department E. Alarcon 721 Barton Springs Road City Public Service Austin, TX 78704

NOC-AE-05001 841 Attachment 1 Licensee's Evaluation

NOC-AE-05001841 Attachment I Page 1 of 6 LICENSEE'S EVALUATION

1.0 DESCRIPTION

This letter is a request to amend Operating Licenses NPF-76 and NPF-80 for South Texas Project (STP) Units 1 and 2. The proposed amendment revises Technical Specification (TS) 3.4.6.1, "Reactor Coolant System Leakage Detection Systems," to require specifically the containment radioactivity monitor (particulate channel) to be operable in Modes 1, 2, 3 and 4. The proposed amendment eliminates the gaseous channel from Limiting Condition for Operation (LCO) 3.4.6.1.

Additionally, corresponding changes to Surveillance Requirement 4.4.6.2.1, "Reactor Coolant System Operational Leakage," are also requested.

STPNOC requests approval of the proposed amendment by February 28, 2006. Once approved, the amendment shall be implemented within 90 days.

2.0 PROPOSED CHANGE

The current TS LCO 3.4.6.1 states the following:

3.4.6.1 The following Reactor Coolant System Leakage Detection Instrumentation shall be OPERABLE:

a. One Containment Atmosphere Radioactivity Monitor (gaseous or particulate), and

b. The Containment Normal Sump Level and Flow Monitoring System.

The proposed amendment would revise this LCO to state the following:

3.4.6.1 The following Reactor Coolant System Leakage Detection Instrumentation shall be OPERABLE:

a. The Containment Radioactivity Monitor (particulate channel), and

b. The Containment Normal Sump Level and Flow Monitoring System.

Corresponding changes to SR 4.4.6.2.I.a are also proposed, which would remove the gaseous channel from containment atmosphere monitoring requirements.

The associated change to the TS Bases will be made accordingly as a part of the implementation of this license amendment.

NOC-AE-05001841 Attachment I Page 2 of 6

3.0 BACKGROUND

System Design

The Reactor Coolant System (RCS) Leakage Detection Systems required by TS 3.4.6.1 are provided to monitor and detect leakage from the Reactor Coolant Pressure Boundary (RCPB).

The system was designed to conform with NRC General Design Criterion (GDC) 30 and Regulatory Guide (RG) 1.45.

RG 1.45, "Reactor Coolant Pressure Boundary Leakage Detection Systems," dated May 1973, establishes requirements for detection and monitoring of leakage of reactor coolant into the containment area. RG 1.45 states that instrument sensitivities of 10-9 pCi/cc radioactivity for air particulate monitoring and 10-6 pCi/cc radioactivity for radiogas monitoring are practical for reactor coolant pressure boundary leakage detection systems. It also states that detector systems should respond to a one gal/min, or its equivalent, leakage increase in one hour or less. RG 1.45 goes on to say that "in analyzing the sensitivity of leak detection systems using airborne particulate or gaseous radioactivity, a realistic primary coolant radioactivity concentration assumption should be used. The expected values used in the plant environmental report would be acceptable." The expected percentage of leaking fuel used in the plant environmental report is 0.12 percent. This report also assumes a continuous low volume purge of the containment building at a rate of 5,000 cfm.

STP's RCS Leakage Detection instrumentation consists of a Containment Atmosphere Radioactivity Monitor (gaseous or particulate) and the Containment Normal Sump Level and Flow Monitoring System.

The particulate and gaseous channels of the Containment Atmosphere Radioactivity Monitor are used as part of the RCPB leakage detection system. The sensitivity and response time of the particulate channel, which is used for monitoring unidentified leakage to the containment, are sufficient to detect an increase in leakage rate of the equivalent of one gal/min within one hour in accordance with assumptions made consistent with RG 1.45.

Leakage Detection Methods The Reactor Containment Building Atmosphere Monitor is in place to monitor containment air for particulate, iodine, and gaseous activities. The monitor continuously samples from the containment atmosphere, which is drawn outside the containment in a closed system. The particulate channel of that monitor detects isotopes, which quantitatively relates the activity increase to the magnitude of RCPB leakage into the Containment.

The particulate channel's sensitivity and response time have been determined with the conclusion that the particulate channel is capable of measuring the equivalent of a one gal/min RCPB leakage to the Containment within one hour. Measurement interferences due to external ambient gamma background, naturally occurring airborne radioactivity, and normally undetectable RCPB leakage were considered. The display for this monitor is in units of pCi/cc.

NOC-AE-05001841 Attachment I Page 3 of 6 The alarm setpoint is calculated on the basis of monitor sensitivity, which corresponds to an RCPB leakage rate of one gal/min, such that the alarm is initiated within one hour from the start of the increased leak. Currently, the Reactor Containment Building Atmosphere particulate Alert Alarm and High Alarm design setpoints are approximately 8.4x10 pCi/cc and 1.0x10 6 pCi/cc respectively. Additionally, the Alert setpoint is normally lowered to increase the sensitivity and improve operator awareness of changes in atmosphere radioactivity levels.

The display for the noble gas channel of the monitor is in units of pCi/cc. The alarm setpoint is calculated on the basis of monitor sensitivity, which corresponds to an RCPB leakage rate of one gal/min, such that the alarm is initiated within one hour from the start of the increased leak.

Assuming 0.12 percent failed fuel based on the plant environmental report, the Reactor Containment Building Atmosphere gaseous channel Alert Alarm and High Alarm design setpoints are both approximately 5.8x10-3i Ci/cc. With the current RCS leakage and the low fuel clad leakage values, the majority of the gas that is sensed by the gaseous channel is activated Argon which is normally present in air and is activated by proximity to the high radiation field in the immediate vicinity of the reactor vessel. During normal operations, air flow inside containment distributes this activated gas throughout containment, such that a measured background level of approximately 8x10-6 pCi/cc is present.

Need for the Amendment During the period since startup of the South Texas Project (STP) to the present, the gaseous channel of the containment atmosphere radiation monitor has become less effective for RCS leakage detection due to improved fuel integrity and the resultant reduced RCS radioactivity levels. The gaseous channel was designed in accordance with the sensitivities specified in RG 1.45, (i.e., assuming 0.12 percent failed fuel) its alarm setpoint has been set as low as practicable, is fully functioning in accordance with its design requirements, and is meeting the current TS surveillance requirements. However, due to the high normal background levels of activated gas inside containment, the gaseous channel is unable to promptly detect RCS leakage with reduced reactor coolant radioactivity levels. Since TS 3.4.6.1 allows use of either the gaseous or the particulate channel to satisfy the requirement for one containment atmosphere radioactivity monitor, and the capability of the gaseous channel has been determined to be insufficient, removal of the gaseous channel requirement in TS 3.4.6.1 (and SR 4.4.6.2.1.a) is warranted.

4.0 TECHNICAL ANALYSIS

Detection of RCS leakage using radiation monitors is affected by the quantity of isotopes contained in the reactor coolant and the background level of radiation around the detectors.

With the level of radioactivity in the reactor coolant assumed in UFSAR, both the containment atmosphere particulate and gaseous radioactivity channels are capable of detecting a one gal/min leak in one hour. However, the level of radioactivity in the STP reactor coolant is normally much lower than the value that was assumed in the UFSAR.

NOC-AE-05001841 Attachment I Page 4 of 6 The ransge of the containment atmosphere particulate radioactivity channel isl.6x10-" to 1.6x10- iCi/cc, which meets the sensitivity criteria specified in RG 1.45. Varying detector background, RCS activity level, and failed fuel conditions contribute to changes in the particulate monitors' detection capabilities.

The containment atmosphere gaseous radioactivity channel has a range of approximately 5.4x 10-7 to 5.4x10-l ACi/cc, which also meets the sensitivity criteria specified in RG 1.45. As the detector background increases, either the time to detect a one gal/min leak would increase or the detectable RCS leak rate would be greater than one gal/min within the specified timeframe. At elevated RCS activity/failed fuel conditions, a one gal/min leak would be detectable within one hour even with a much higher detector background. For lower RCS activity levels, as described above, a one gal/min leak becomes more difficult to detect using the containment atmosphere gaseous radioactivity monitor.

Additional diverse means of leakage detection are available as part of the overall STPNOC leakage detection capability. For example, non-TS required Volume Control Tank (VCT) level is monitored in the control room with a level recorder. The level recorder is sensitive enough to record a one gal/min leak rate within one hour during steady state operations. RCS mass balance is performed in accordance with TS 3.4.6.1 with one inoperable RCS leakage detection monitor. The mass balance calculated from performing the surveillance can provide indication of a one gal/min leakrate change. Finally, additional non-TS required containment temperature and pressure instrumentation provide indication in the main control room.

It should be noted that STPNOC intends to maintain the containment atmosphere gaseous radioactivity monitor functional and available in accordance with normal non-TS equipment practices.

In summary, while the proposed amendment eliminates the gaseous channel from TS 3.4.6.1 (and SR 4.4.6.2.1.a), it results in a more restrictive requirement in the LCO for the containment atmosphere radioactivity monitor (i.e., the particulate channel). The proposed amendment continues to require diverse means of leakage detection equipment with capability to promptly detect RCS leakage consistent with the STP licensing basis.

5.0 REGULATORY SAFETY ANALYSIS 5.1 No Significant Hazards Consideration STPNOC has evaluated whether a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No

NOC-AE-05001841 Attachment I Page 5 of 6 The proposed change has been evaluated and determined to not increase the probability or consequences of an accident previously evaluated. The proposed change does not make any hardware changes and does not alter the configuration of any plant system, structure or component (SSC). The proposed change only removes the containment atmosphere gaseous radioactivity monitor as an option for meeting the operability requirement for TS 3.4.6.1, and correspondingly from the requirements of SR 4.4.6.2.1.a.

Therefore, the probability of occurrence of an accident is not increased. The TS will continue to require diverse means of leakage detection equipment, thus ensuring that leakage due to cracks would continue to be identified prior to breakage and the plant shutdown accordingly. Additionally, the proposed change is not modeled in the South Texas Project probabilistic risk assessment and has no impact on core damage frequency or large early release frequency. Therefore, the consequences of an accident are not increased.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change does not involve the use or installation of new equipment and the currently installed equipment will not be operated in a new or different manner. No new or different system interactions are created and no new processes are introduced. The proposed changes will not introduce any new failure mechanisms, malfunctions, or accident initiators not already considered in the design and licensing bases. The proposed change does not affect any SSC associated with an accident initiator. Based on this evaluation, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No The proposed change does not make any alteration to any RCS leakage detection components. The proposed change only removes the gaseous channel of the containment atmosphere radioactivity monitor as an option for meeting the operability requirement for TS 3.4.6.1, and correspondingly from the requirements of SR 4.4.6.2.1.a. The proposed amendment continues to require diverse means of leakage detection equipment with capability to promptly detect RCS leakage. Although not required by TS, additional diverse means of leakage detection capability are available. Based on this evaluation, the proposed change does not involve a significant reduction in a margin of safety.

NOC-AE-05001841 Attachment I Page 6 of 6 Based on the above, STPNOC concludes that the proposed amendment involves no significant hazards consideration under the standards set forth in 10CFR50.92, and a finding of "no significant hazards consideration" is justified.

5.2 Applicable Regulatory Requirements/Criteria 10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants," Criterion 30, "Quality of reactor coolant pressure boundary," requires that means be provided for detecting and, to the extent practical, identifying the location of the source of reactor coolant leakage.

The various means for detecting reactor coolant leakage at STPNOC were previously discussed in Section 3.0, "Background."

The specific attributes of the reactor coolant leakage detection systems are outlined in Regulatory Positions 1 through 9 of RG 1.45. STP conformance with RG 1.45 is described in UFSAR Section 3.12, "Conformance with NRC Regulatory Guides." It should be noted that Regulatory Position 9 specifies that the TS should include the limiting conditions for identified and unidentified leakage and address the availability of various types of instruments to assure adequate coverage at all times; however, Position 9 does not specify how many instruments shall be contained in the TS. Both the containment sump monitor and the containment atmosphere:.

radioactivity particulate channel satisfy the RG 1.45 criteria for detecting RCS leakage.

Therefore, removal of the gaseous channel of the containment radiation monitor from the TS is not in conflict with this Regulatory Position.

10 CFR 50.36, "Technical Specifications," paragraph (c)(2)(ii)(A), specifies that a TS limiting condition for operation be established for installed instrumentation that is used to detect and indicate in the control room a significant abnormal degradation of the RCPB. Currently, the instrumentation addressed in TS 3.4.6.1 satisfies this requirement. The current instrumentation addressed in TS 3.4.6.1 includes one containment sump monitor and one containment atmosphere radioactivity monitor (gaseous or particulate). The removal of the gaseous channel of the containment atmosphere radioactivity monitor from the TS is not in conflict with this requirement as the containment sump monitor and the particulate channel of the containment atmosphere radioactivity monitor will remain in the TS LCO.

6.0 ENVIRONMENTAL CONSIDERATION

STPNOC has evaluated the proposed changes and determined the changes do not involve (1) a significant hazards consideration, (2) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (3) a significant increase in the individual or cumulative occupational exposure. Accordingly, the proposed changes meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9), and an environmental assessment of the proposed changes is not required.

NOC-AE-05001841 Attachment 2 Proposed Technical Specification Change (Mark-up)

NOC-AE-05001 841 Attachment 2 Page lof 2 REACTOR COOLANT SYSTEM 3/4.4.6 REACTOR COOLANT SYSTEM LEAKAGE LEAKAGE DETECTION SYSTEMS LIMITING CONDITION FOR OPERATION 3.4.6.1 The following Reactor Coolant System Leakage Detection Instrumentation shall be OPERABLE:

a.  ; 14m Containment Atmosphere Radioactivity Monitor {gas ou particulateh-nnel, and

b. The Containment Normal Sump Level and Flow Monitoring System.

APPLICABILITY: MODES 1, 2, 3, and 4.

ACTION:

a. With the required containment atmosphere radioactivity monitor inoperable perform the following actions or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hour3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />s:

1) Restore i Jcontainment atmosphere monitorygi [parlicuLais channeD to OPERABLE status within 30 days and,

2) Obtain and analyze a grab sample of the containment atmosphere for ____

particulate radioactivity at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or

3) Perform a Reactor Coolant System water inventory balance at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

b. With the required containment normal sump level and flow monitoring system inoperable perform the following actions or be in at least HOT STANBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hour3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />s:

1) Restore the containment normal sump and flow monitoring system to OPERABLE status within 30 days and,

2) Perform a Reactor Coolant System water inventory balance at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

c. With both a. and b. inoperable, enter 3.0.3.

SURVEILLANCE.REQUIREMENTS 4.4.6.1 The Leakage Detection Systems shall be demonstrated OPERABLE by:

a. Containment Atmosphere p -. _ Monitoring Systernnel performance of the following:

1) CHANNEL CHECK at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, and

2) CHANNEL CALIBRATION at least once per 18 months

b. Containment Normal Sump Level and Flow Monitoring System performance of CHANNEL CALIBRATION at least once per 18 months.

SOUTH TEXAS - UNITS 1 & 2 3/4 4-19 Unit 1 - Amendment No. 86, 153 Unit 2 - Amendment No. 3 141

NOC-AE-05001841 Attachment 2 Page 2 of 2 REACTOR COOLANT SYSTEM OPERATIONAL LEAKAGE SURVEILLANCE REQUIREMENTS (Continued) 4.4.6.2.1 Note: this requirement is not applicable to primary-to-secondary leakage (refer to 4.4.6.2.3).

Reactor Coolant System operational leakage shall be demonstrated to be within each of the above limits by:

a. Monitoring the containment atmosphere _ particulate radioactivity channef at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />;

b. Monitoring the containment normal sump inventory and discharge at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />;

c. Performance of a Reactor Coolant System water inventory balance at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and (1)

d. Monitoring the Reactor Head Flange Leakoff System at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

4.4.6.2.2 Each Reactor Coolant System Pressure Isolation Valve specified in Table 3.4-1 shall be demonstrated OPERABLE by verifying leakage to be within its limit:

a. At least once per 18 months,

b. Prior to entering MODE 2 whenever the plant has been in COLD SHUTDOWN for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or more and if leakage testing has not been performed in the previous 9 months,

c. Prior to returning the valve to service following maintenance, repair or replacement work on the valve, and

d. Prior to entering MODE 2 following valve actuation due to automatic or manual action or flow through the valve except for valves XRH0O60 A, B, C, and XRHOO61 A, B, C.

4.4.6.2.3 Primary-to-secondary leakage shall be verified s 150 gallons per day through any one steam generator at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. (1)

The provisions of Specification 4.0.4 are not applicable for entry into MODE 3 or 4.

(1) Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishment of steady state operation.

SOUTH TEXAS - UNITS 1 & 2 3/4 4-21 Unit 1 - Amendment No. 22,134, 164 Unit 2 - Amendment No. 42423, 154