ML18058A363

Application for Amend to License DPR-20,changing TSs to Incorporate Generic Ltr 90-06 PORV Requirements for Power Operation & Modifying Pcs Overpressure Protection Spec Venting Requirements

ML18058A363
Person / Time
Site:	Palisades
Issue date:	04/15/1992
From:	Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18058A364	List: ML18058A363 ML18058A365
References
GL-90-06, GL-90-6, NUDOCS 9204270064
Download: ML18058A363 (8)

Text

consumers Power GB Slade General Manager POWERiNii MICHlliAN'S PROliRESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 April 15, 1992 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - TECHNICAL SPECIFICATIONS CHANGE REQUEST - OVERPRESSURE PROTECTION Enclosed is a request for a change to the Palisades Technical Specifications to incorporate GL 90-06 Power Operated Relief Valve (PORV) requirements for power operation, and to modify the Primary Coolant System (PCS) overpressure protection specification venting requirements.

The proposed specification for PORV operability during power operation, 3.1.8.1, implements the applicable model Technical Specifications attached to GL 90-06.

This part of the change request completes our response to GL 90-06 in accordance with our letter of December 26, 1990.

The proposed PCS venting changes are the result of analyses conducted in conjunction with the installation of the new PORVs and block valves in 1989. It replaces the 1.3 square inch vent size requirements with vent flow capacity requirements, restructures the Action statements and modifies the Basis of the specification.

Attachment 1 to the change request contains the proposed Technical Specifications pages; Attachment 2, marked up pages of the existing Technical Specifications showing the proposed changes.

In order to allow the necessary procedure revisions and operator training to be accomplished, it is requested that this change request be made effective 60 days after approval.

• ~

Gerald B Slade General Manager CC Administrator, Region III, USNRC Resident Inspector, Palisades Attachments rJ*00 1

.I I.~* I. . n

._;_ ~J 920427AODg~~ 6~866~55 I *I.

I .

,I I *r "\

'\ PDR p

PDR

,~ ./) A'CMS' ENER<SY COMPANY

1 CONSUMERS POWER COMPANY Docket 50-255 Request for Change to the Technical Specifications License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specifications contained in the Facility Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on February 21, 1991, for the Palisades Plant be changed as described below:

I. Changes A. Technical Specification 3.1.8 is changed as follows:

1. A new Specification 3.1.8.1, PORV requirements when the plant is at Hot Standby and above, has been added to implement the model Technical Specification of GL 90-06.

2. Existing Specification 3.1.8.1, PORV requirements when below 430°F, has been renumbered as 3.1.8.2, and revised to:

a. Coordinate the Action statements with those of the proposed 3.1.8.1. .

b. Specify a minimum vent flow capacity instead of the existing specification of a minimum flow area.

c. Delete the exception to the provisions of 3.0.3 and add an exception to 4.0.4.

d. Simplify and clarify the wording.

This change request proposes use of a stipulated vent flow capability rather than a stipulated vent area to avoid possible misinterpretation of the specification. For~xample,. a flow area of 1.3 square inches would be provided by two parallel paths each having an area of 0.65 square inches, or by a single vent of 1.3

• square inches on the.end of a long run of pipe. Neither of these examples would necessarily provide the intended relief capacity.

3. The Basis section for Specification 3.1.8 has been revised to discuss the newly added requirements.

B. Table 3.17.4, Item 11, "PORV Isolation Valve Position Indication" is revised to refer to specification 3.1.8, rather than to repeat the venting criterion and to use the term "Block Valve", rather than "Isolation Valve.".

C. Surveillance Requirement 4.1.1 has been revised to include additional testing in accordance with GL 90-06.

n 2

II. Discussion A. The proposed Palisades PORV specifications differ from the model Technical Specifications in form and in content. Palisades does not utilize Standard Technical Specifications, therefore, the format of the proposed specifications differs from those provided in GL 90-06.

Palisades safety analyses do not assume automatic PORV operation above a temperature of 430°F, but do assume automatic, variable setpoint operation when below 430°F. Existing specifications address PORV operability below 430°F. Two specifications are proposed; one applicable at Hot Standby and above, and one below 430°F.

Proposed specification 3.1.8.1, applicable at Hot Standby and above, stipulates requirements similar to those of GL 90-06 specification 3.4.4. Proposed specification 3.1.8.2 maintains the requirements of existing Palisades specification 3.1.8.1.

1. The proposed specification 3.1.8.1 differs from GL 90-06 specification 3.4.4 for the following reasons:

a. The wording of proposed specification 3.1.8.1 differs from that of GL 90-06 specification 3.4.4 in order address the required function of two operable flow paths, rather than to simply address the required components.

b. Action "a" of GL 90-06 was omitted from the proposed specification for two reasons. First, 'there is neither a reference to a seat leakage limit in the GL 90-06 LCO nor in the GL 90-06 surveillance requirements, so it would not be possible to determine how much leakage would make the valve inoperable. Second, Palisades Technical Specifications already contain limitations on PCS leakage and Actions to be taken if those limitations are exceeded. Adding an Action for PCS leakage in the PORV specification would, therefore, be redundant.

c. Actions "b" and "d" of GL 90-06 were combined for a single inoperable valve, Actions "c" and "d" of GL 90-06 were combined for two inoperable valves, to better address the PORV function, rather ~han only the individual components.

The proposed Action statements address one PORV and the opposite block valve being inoperable, which those of GL 90-06 did not.

d. The proposed Actions do not force the plant into a mode where the PORVs are required for pressure control. Instead, the proposed Actions require a shutdown, but not a cooldown.

The intent is to allow repairs to be made without entering conditions where the valves are required for LTOP, when possible, or to allow planning of a controlled cooldown when the valves cannot be repaired while the PCS is above 430°F.

3

e.

• All completion times are referenced to discovery that the Action statement applies. The completion time proposed for reaching Hot Shutdown is the same as that currently specified in the Palisades specifications for the Reactor Protective System and other equipment. Note that Palisades "HOT SHUTDOWN" definition is similar to the Standard Technical Specifications "HOT STANDBY" definition.

f. The 3.0.4 exception is limited to specification 3.1.8.2, thus prohibiting a startup with an inoperable PORV or block valve.

g. The removal of power from a block valve which has been closed to isolate an inoperable PORV was not required because the time in this condition is limited to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.-

Most PORV inoperabilities are administrative involving no actual loss of function, or involving failures which result in the PORV being failed closed, rather than resulting in a potential for spurious opening. In addition, a failure which would cause a closed block valve to drive open is unlikely, and for such a failure to occur concurrently.with a failure of the associated PORV, within a given 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period is even more remote. The proposed Action maintains pressure control capability when the PORV is still functional but allows power removal if it is deemed necessary.

2. The change, in specification 3.1.8.2, from specifying a particular vent area to specifying a vent path flow capability more clearly aligns the requirements of the specification w~th the assumptions of the analyses. The need for a chang~ occurred because it was discovered that newly installed PCS manual vent valves, which had been understood to have an effective area of 1.33 square inches, actually had an effective area of 1.228 square inches, slightly smaller than the specified vent area of l.~ square inches.

Analysis showed that the newly installed manual vent valve area was sufficient to meet Appendix G criterion. However, since the valves did not meet the area requirement of the Technical Specification, they have not been relied upon to meet the venting requirements of LCO 3.1.8 or of Table 3.17.4.

The basis for the 1.3 square inch vent area requirement is not clear. It is believed, however, that it was the choking area of one of the original Dresser PORVs. The intent of the requirement is to protect the primary coolant system (PCS) from pressure transients which could exceed the 10 CFR 50, Appendix G, limits with the PORVs inoperable. No analysis has been found that showed a 1.3 square inch vent area would protect the PCS from exceeding the Appendix G curve limit.

4 Analysis concluded that manual vent valves PC~514 and PC-515 will provide a relief capacity of 167 gpm at a PCS pressure of =115 psig, well below the minimum 331 psig limit (Appendix G curve limit for a 40°F/hr heat-up). This relief capacity will protect the PCS against a pressure transient caused by a maximum charging/letdown imbalance coincident with a 40°F/hr PCS heat-up rate and a 60°F/hr pressurizer heat-up rate.

Two other pressure transients, a high pressure safety injection (HPSI) pump start and a primary coolant pump (PCP) start, discussed in the proposed Technical Specification 3.1.8 Basis, are also precluded. With the PCS in a ~ented and depressurized state, the PCS would be below 212°F. Technical Specification 3.3.2g requires both HPSI pumps to be rendered inoperable below 260°F and, with the system depressurized, normal operating procedures prohibit a primary coolant pump start due to insufficient pump net positive suction head (NPSH).

Additional analysis confirmed that the SDC relief capacity, prior to the installation of PC-514 and PC-515, was adequate to provide overpressure protection of the SDC system for the pressure transient evaluated for PC-514 and PC-515.

Therefore, the 1.3 square inch requirement can be replaced with a requirement to have a vent capable of relieving 167 gpm at a PCS pressure less than or equal to 300 psig. The 300 psig limit was chosen to allow for future Appendix G limits below the present limit. The Appendix G limits are revised periodically to account for the continuing effects of irradiation on the PCS.

The basis for Technical Specification 3.1.8 is updated to provide the limitations that apply to the new requirements which ensure an overpressurization of the PCS does not occur.

B. Table 3.17.4, item 11, PORV block valve position indication, has been changed to utilize the term "block valve" rather than "isolation Valve" for consistency with specification 3.1.8 and with general plant usage. The associated Permissible Bypass Condition entry has been changed to reference specification 3.1.8, rather than to repeat the specific PCS vent requirement.

C. Surveillance Requirement 4.1.1 has been revised to include requirements to cycle each PORV and each block valve each 18 months.

The block valve surveillance frequency of "once per 92 days" suggested in GL 90-06 is inappropriate for Palisades. Palisades does not assume automatic PORV operation, other than for LTOP, in any safety analyses, and operates with the block valves closed when above the LTOP range.

Opening the block valves during power operation may cause the PORVs to momentarily relieve, with a subsequent increased chance of seat leakage. A frequency of "18 Months" is proposed.

5 III. Analysis of No Significant Hazards Consideration Consumers Power Company finds the activities associated with this proposed Technical Specifications change involve no significant hazards and accordingly, a no significant hazards determination per 10CFR50.92(c) is justified. The following evaluation supports the finding that operation of the facility in accordance with the proposed change would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed Technical Specification requiring Operability of the PORVs and their block valves does not alter plant operation or configuration in any way. It is current practice to maintain these valves in an Operable condition to meet the requirements of existing Specification 3.1.8, which is applicable when below 430°F. The effect of the proposed changes is to extend the applicability of the Operability requirement for these valves. The addition of PORV Operability requirements when at Hot Standby and above would not involve a significant increase in the probability or consequences of an accident previously evaluated.

Replacing the requirements to vent the PCS through a 1.3 square inch vent with a vent capable of relieving 167 gpm at a pressure less than the Appendix G limits will not significantly increase the probability or consequences of an overpressurization event occurring. The 1.3 square inch vent area in Technical Specification 3.1.8 was intended to be a means of protecting the Primary Coolant System (PCS)' from exceeding the limit of the 10 CFR 50, Appendix G, curve following an overpressure transient. Analysis has shown that manual vent valves PC-514 and PC-515.will provide a relief capacity of 167 gpm at a PCS pressure of =115 psig, well below the minimum 331 psig limit (Appendix G curve limit for a 40°F/hr heat-up). This relief capacity will protect the PCS against a pressure transient caused by a maximum charging/letdown imbalance coincident with a 40°F/hr PCS heat-up rate and a 60°F/hr pressurizer heat-up rate.

Two other pressure transients, a.High Pressure Safety Injection (HPSI) pump start and a Primary Coolant Pump (PCP) start, are also precluded.

With the PCS in a vented and depressurized state, the PCS would be below 212°F. Existing technical specifications require both HPSI pumps to be rendered inoperable below 260°F and, with the system depressurized, normal operating procedures prohibit a PCP start due to insufficient pump net positive suction head (NPSH).

Therefore, the 1.3 square inch requirement can be replaced with a requirement to have a vent capable of relieving 167 gpm at a PCS pressure .less than or equal to the Appendix G limit with no significant increase in the probability or consequences of an overpressurization event occurring.

6

2. Create the possibility of a new or different kind of accident from any previously evaluated.

The addition of PORV Operability requirements when at Hot Standby and above will not alter plant operation or configuration. It will not alter any equipment or analyses. Therefore the addition of these PORV operability requirements will not create the possibility of a new or different kind of accident from any previously evaluated.

The new technical specifications requirements for PCS vent capacity will provide an equivalent or better, overpressure protection as compared to the existing requirement. No analysis has been found that shows that the existing 1.3 square inch vent area will protect the PCS from exceeding the Appendix G curve limit. However, analysis has been developed which shows that manual vent valves PC-514 and PC-515 will provide adequate relief capacity, maintaining PCS pressure within* the 10 CFR 50, Appendix G, limits. Furthermore, two other pressure transients, a HPSI pump start and a PCP start, are also precluded by either existing technical specifications or normal plant operating procedures.

Another related analysis has shown that relief valve RV-3164, the Low Pressure Safety Injection (LPSI) pumps, the LPSI pump seals, and the system piping of the shutdown cooling system have the capability of providing adequate overpressure protection to the shutdown cooling system.

The addition of the manual vent valves do not introduce a vent path where a vent path had not previously existed. Therefore, the possibility of an accident of a new or different type, than previously evaluated in the FSAR, will not be created.

3. Involve a significant reduction in a margin of safety.

The margin of safety will not be reduced by the proposed Technical_

Sp~cfficatidns chang~s. The extensio~ of PORV Operability requirements has no effect on any margin of safety. The previous requirement assumed that a vent with an equivalent flow area as the original PORV would provide the same relief as the PORV itself and gave no consideration to how that flow area should factor in system losses or vent location. The new technical specification requirement offers a means to ensure the PCS will be protected against all achievable overpressure transients for the system configuration, with analyses to support it.

• 7 IV. Conclusion The Palisades Plant Review Committee has reviewed this Technical Specifications Change Request and has determined that proposing this change does not involve an unreviewed safety question. Further, the change involves no significant hazards consideration. This change has been reviewed by the Nuclear Performance Assessment Department. A copy of this Technical Specifications Change Request has been sent to the State of Michigan official designated to receive such Amendments to the Operating License.

CONSUMERS POWER COMPANY To the best of my knowledge, information and belief, the contents of this Technical Specifications Change Request are truthful and complete.

By~a:J. ~1~~-----

David P Hoffman, Vi Nuclear Operations Sworn and subscribed to before me this jJ day of ~ 1992.

Lo. Ow,__0m &fU,L Notary Public

, Michigan My commission expires

• .C:eANN MORSEi NOT,ARY PUBLIC' YA!'! BU.REN COUNTY, STATE OF MICHIGAN MY: .COMMISSION EXPIRES 06*()6**~-~ .......